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Essay On The Volcano – 10 Lines, Short & Long Essay For Kids

Key Points To Remember When Writing An Essay On The Volcano For Lower Primary Classes

10 lines on the volcano for kids, a paragraph on the volcano for children, short essay on volcano in 200 words for kids, long essay on volcano for children, interesting facts about volcanoes for children, what will your child learn from this essay.

A volcano is a mountain formed through an opening on the Earth’s surface and pushes out lava and rock fragments through that. It is a conical mass that grows large and is found in different sizes. Volcanoes in Hawaiian islands are more than 4000 meters above sea level, and sometimes the total height of a volcano may exceed 9000 meters, depending on the region it is found. Here you will know and learn how to write an essay on a volcano for classes 1, 2 & 3 kids. We will cover writing tips for your essay on a volcano in English and some fun facts about volcanoes in general.

Volcanoes are formed as a result of natural phenomena on the Earth’s surface. There are several types of volcanoes, and each may emit multiple gases. Below are some key points to remember when writing an essay on a volcano:

• Start with an introduction about how volcanoes are formed. How they impact the Earth, what they produce, and things to watch out for.
• Discuss the different types of volcanoes and talk about the differences between them.
• Cover the consequences when volcanoes erupt and the extent of the damage on Earth.
• Write a conclusion paragraph for your essay and summarise it. 

When writing a few lines on a volcano, it’s crucial to state interesting facts that children will remember. Below are 10 lines on volcanoes for an essay for classes 1 & 2 kids.

• Some volcanoes erupt in explosions, and then some release magma quietly.
• Lava is hot and molten red in colour and cools down to become black in colour. 
• Hot gases trapped inside the Earth are released when a volcano erupts.
• A circle of volcanoes is referred to as the ‘Ring of Fire.’
• Volcano formations are known as seismic activities.
• Active volcanoes are spread all across the earth. 
• Volcanoes can remain inactive for thousands of years and suddenly erupt.
• Most volcanic eruptions occur underwater and result from plates diverging from the margins.
• Volcanic hazards happen in the form of ashes, lava flows, ballistics, etc.
• Volcanic regions have turned into tourist attractions such as the ones in Hawaii.

Volcanoes can be spotted at the meeting points of tectonic plates. Like this, there are tons of interesting facts your kids can learn about volcanoes. Here is a short paragraph on a volcano for children:

A volcano can be defined as an opening in a planet through which lava, gases, and molten rock come out. Earthquake activity around a volcano can give plenty of insight into when it will erupt. The liquid inside a volcano is called magma (lava), which can harden. The Roman word for the volcano is ‘vulcan,’ which means God of Fire. Earth is not the only planet in the solar system with volcanoes; there is one on Mars called the Olympus Mons. There are mainly three types of volcanoes: active, dormant, and extinct. Some eruptions are explosive, and some happen as slow-flowing lava.

Small changes occur in volcanoes, determining if the magma is rising or not flowing enough. One of the common ways to forecast eruptions is by analysing the summit and slopes of these formations. Below is a short essay for classes 1, 2, & 3:

As a student, I have always been curious about volcanoes, and I recently studied a lot about them. Do you know? Krakatoa is a volcano that made an enormous sound when it exploded. Maleo birds seek refuge in the soil found near volcanoes, and they also bury their eggs in these lands as it keeps the eggs warm. Lava salt is a popular condiment used for cooking and extracted from volcanic rocks. And it is famous for its health benefits and is considered superior to other forms of rock or sea salts. Changes in natural gas composition in volcanoes can predict how explosive an eruption can be. A volcano is labelled active if it constantly generates seismic activity and releases magma, and it is considered dormant if it has not exploded for a long time. Gas bubbles can form inside volcanoes and blow up to 1000 times their original size!

Volcanic eruptions can happen through small cracks on the Earth’s surface, fissures, and new landforms. Poisonous gases and debris get mixed with the lava released during these explosions. Here is a long essay for class 3 kids on volcanoes:

Lava can come in different forms, and this is what makes volcanoes unique. Volcanic eruptions can be dangerous and may lead to loss of life, damaging the environment. Lava ejected from a volcano can be fluid, viscous, and may take up different shapes. 

When pressure builds up below the Earth’s crust due to natural gases accumulating, that’s when a volcanic explosion happens. Lava and rocks are shot out from the surface to make room on the seafloor. Volcanic eruptions can lead to landslides, ash formations, and lava flows, called natural disasters. Active volcanoes frequently erupt, while the dormant ones are unpredictable. Thousands of years can pass until dormant volcanoes erupt, making their eruption unpredictable. Extinct volcanoes are those that have never erupted in history.

The Earth is not the only planet in the solar system with volcanoes. Many volcanoes exist on several other planets, such as Mars, Venus, etc. Venus is the one planet with the most volcanoes in our solar system. Extremely high temperatures and pressure cause rocks in the volcano to melt and become liquid. This is referred to as magma, and when magma reaches the Earth’s surface, it gets called lava. On Earth, seafloors and common mountains were born from volcanic eruptions in the past.

What Is A Volcano And How Is It Formed?

A volcano is an opening on the Earth’s crust from where molten lava, rocks, and natural gases come out. It is formed when tectonic plates shift or when the ocean plate sinks. Volcano shapes are formed when molten rock, ash, and lava are released from the Earth’s surface and solidify.

Types Of Volcanoes

Given below various types of volcanoes –

1. Shield Volcano

It has gentle sliding slopes and ejects basaltic lava. These are created by the low-viscosity lava eruption that can reach a great distance from a vent.

2. Composite Volcano (Strato)

A composite volcano can stand thousands of meters tall and feature mudflow and pyroclastic deposits.

3. Caldera Volcano

When a volcano explodes and collapses, a large depression is formed, which is called the Caldera.

4. Cinder Cone Volcano

It’s a steep conical hill formed from hardened lava, tephra, and ash deposits.

Causes Of Volcano Eruptions

Following are the most common causes of volcano eruptions:

1. Shifting Of Tectonic Plates

When tectonic plates slide below one another, water is trapped, and pressure builds up by squeezing the plates. This produces enough heat, and gases rise in the chambers, leading to an explosion from underwater to the surface.

2. Environmental Conditions

Sometimes drastic changes in natural environments can lead to volcanoes becoming active again.

3. Natural Phenomena

We all understand that the Earth’s mantle is very hot. So, the rock present in it melts due to high temperature. This thin lava travels to the crust as it can float easily. As the area’s density is compromised, the magma gets to the surface and explodes.

How Does Volcano Affect Human Life?

Active volcanoes threaten human life since they often erupt and affect the environment. It forces people to migrate far away as the amount of heat and poisonous gases it emits cannot be tolerated by humans.

Here are some interesting facts:

• The lava is extremely hot!
• The liquid inside a volcano is known as magma. The liquid outside is called it is lava.
• The largest volcano in the solar system is found on Mars.
• Mauna Loa in Hawaii is the largest volcano on Earth.
• Volcanoes are found where tectonic plates meet and move.

Your child will learn a lot about how Earth works and why volcanoes are classified as natural disasters, what are their types and how they are formed.

Now that you know enough about volcanoes, you can start writing the essay. For more information on volcanoes, be sure to read and explore more.

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ENCYCLOPEDIC ENTRY

A volcano is an opening in a planet or moon’s crust through which molten rock and gases trapped under the surface erupt, often forming a hill or mountain.

Volcanic eruption

Volcanic eruptions can create colorful and dramatic displays, such as this eruption of this volcano in the Virunga Moutains of the Democratic Republic of the Congo.

Photograph by Chris Johns

A volcano is an opening in a planet or moon’s crust through which molten rock, hot gases, and other materials erupt . Volcanoes often form a hill or mountain as layers of rock and ash build up from repeated eruptions .

Volcanoes are classified as active, dormant, or extinct. Active volcanoes have a recent history of eruptions ; they are likely to erupt again. Dormant volcanoes have not erupted for a very long time but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future.

Inside an active volcano is a chamber in which molten rock, called magma , collects. Pressure builds up inside the magma chamber, causing the magma to move through channels in the rock and escape onto the planet’s surface. Once it flows onto the surface the magma is known as lava .

Some volcanic eruptions are explosive, while others occur as a slow lava flow. Eruptions can occur through a main opening at the top of the volcano or through vents that form on the sides. The rate and intensity of eruptions, as well as the composition of the magma, determine the shape of the volcano.

Volcanoes are found on both land and the ocean floor. When volcanoes erupt on the ocean floor, they often create underwater mountains and mountain ranges as the released lava cools and hardens. Volcanoes on the ocean floor become islands when the mountains become so large they rise above the surface of the ocean.

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Related Resources

Essays About Volcanoes: Top 5 Examples and 10 Prompts

Do you need to write essays about volcanoes but don’t know where to start? Check out our top essay examples and prompts to help you write a high-quality essay.

Considered the planet’s geologic architects, volcanoes are responsible for more than 80% of the Earth’s surface . The mountains, craters, and fertile soil from these eruptions give way to the very foundation of life itself, making it possible for humans to survive and thrive.  

Aside from the numerous ocean floor volcanoes, there are 161 active volcanoes in the US . However, these beautiful and unique landforms can instantly turn into a nightmare, like Mt. Tambora in Indonesia, which killed 92,000 people in 1815 .

Various writings are critical to understanding these openings in the Earth’s crust, especially for students studying volcanoes. It can be tricky to write this topic and will require a lot of research to ensure all the information gathered is accurate. 

To help you, read on to see our top essay examples and writing prompts to help you begin writing.

Top 5 Essay Examples

1. short essay on volcanoes by prasad nanda , 2. types of volcanoes by reena a , 3. shield volcano, one of the volcano types by anonymous on gradesfixer.com, 4. benefits and problems caused by volcanoes by anonymous on newyorkessays.com, 5. volcanoes paper by vanessa strickland, 1. volcanoes and their classifications, 2. a dormant volcano’s eruption, 3. volcanic eruptions in the movies, 4. the supervolcano: what is it, 5. the word’s ring of fire, 6. what is a lahar, 7. why does a volcano erupt, 8. my experience with volcanic eruptions, 9. effects of volcanic eruptions, 10. what to do during volcanic disasters.

“The name, “volcano” originates from the name Vulcan, a god of fire in Roman mythology.”

Nanda briefly defines volcanoes, stating they help release hot pressure that builds up deep within the planet. Then, he discusses each volcano classification, including lava and magma’s roles during a volcanic eruption. Besides interesting facts about volcanoes (like the Ojos del Salado as the world’s tallest volcano), Nanda talks about volcanic eruptions’ havoc. However, he also lays down their benefits, such as cooled magma turning to rich soil for crop cultivation.

“The size, style, and frequency of eruptions can differ greatly but all these elements are correlated to the shape of a volcano.”

In this essay, Reena identifies the three main types of volcanoes and compares them by shape, eruption style, and magma type and temperature. A shield volcano is a broad, flat domelike volcano with basaltic magma and gentle eruptions. The strato or composite volcano is the most violent because its explosive eruption results in a lava flow, pyroclastic flows, and lahar. Reena shares that a caldera volcano is rare and has sticky and cool lava, but it’s the most dangerous type. To make it easier for the readers to understand her essay, she adds figures describing the process of volcanic eruptions.

“All in all, shield volcanoes are the nicest of the three but don’t be fooled, it can still do damage.”

As the essay’s title suggests, the author focuses on the most prominent type of volcano with shallow slopes – the shield volcano. Countries like Iceland, New Zealand, and the US have this type of volcano, but it’s usually in the oceans, like the Mauna Loa in the Hawaiian Islands. Also, apart from its shape and magma type, a shield volcano has regular but calmer eruptions until water enters its vents.

“Volcanic eruptions bring both positive and negative impacts to man.”

The essay delves into the different conditions of volcanic eruptions, including their effects on a country and its people. Besides destroying crops, animals, and lives, they damage the economy and environment. However, these misfortunes also leave behind treasures, such as fertile soil from ash, minerals like copper, gold, and silver from magma, and clean and unlimited geothermal energy. After these incidents, a place’s historic eruptions also boost its tourism.

“Beautiful and powerful, awe-inspiring and deadly, they are spectacular reminders of the dynamic forces that shape our planet.”

Strickland’s essay centers on volcanic formations, types, and studies, specifically Krakatoa’s eruption in 1883. She explains that when two plates hit each other, the Earth melts rocks into magma and gases, forming a volcano. Strickland also mentions the pros and cons of living near a volcanic island. For example, even though a tsunami is possible, these islands are rich in marine life, giving fishermen a good living.

Are you looking for more topics like this? Check out our round-up of essay topics about nature .

10 Writing Prompts For Essays About Volcanoes

Do you need more inspiration for your essay? See our best essay prompts about volcanoes below:

Identify and discuss the three classifications of volcanoes according to how often they erupt: active, dormant or inactive, and extinct. Find the similarities and differences of each variety and give examples. At the end of your essay, tell your readers which volcano is the most dangerous and why.

Volcanoes that have not erupted for a very long time are considered inactive or dormant, but they can erupt anytime in the future. For this essay, look for an inactive volcano that suddenly woke up after years of sleeping. Then, find the cause of its sudden eruption and add the extent of its damage. To make your piece more interesting, include an interview with people living near dormant volcanoes and share their thoughts on the possibility of them exploding anytime.

Choose an on-screen depiction of how volcanoes work, like the documentary “ Krakatoa: Volcano of Destruction .” Next, briefly summarize the movie, then comment on how realistic the film’s effects, scenes, and dialogues are. Finally, conclude your essay by debating the characters’ decisions to save themselves.

The Volcanic Explosivity Index (VEI) criteria interpret danger based on intensity and magnitude. Explain how this scale recognizes a supervolcano. Talk about the world’s supervolcanoes, which are active, dormant, and extinct. Add the latest report on a supervolcano’s eruption and its destruction.

Identify the 15 countries in the Circum-Pacific belt and explore each territory’s risks to being a part of The Ring of Fire. Explain why it’s called The Ring of Fire and write its importance. You can also discuss the most dangerous volcano within the ring.

If talking about volcanoes as a whole seems too generic, focus on one aspect of it. Lahar is a mixture of water, pyroclastic materials, and rocky debris that rapidly flows down from the slopes of a volcano. First, briefly define a lahar in your essay and focus on how it forms. Then, consider its dangers to living things. You should also add lahar warning signs and the best way to escape it.

Use this prompt to learn and write the entire process of a volcanic eruption. Find out the equipment or operations professionals use to detect magma’s movement inside a volcano to signal that it’s about to blow up. Make your essay informative, and use data from reliable sources and documentaries to ensure you only present correct details.

If you don’t have any personal experience with volcanic eruptions, you can interview someone who does. To ensure you can collect all the critical points you need, create a questionnaire beforehand. Take care to ask about their feelings and thoughts on the situation.

Write about the common effects of volcanic eruptions at the beginning of your essay. Next, focus on discussing its psychological effects on the victims, such as those who have lost loved ones, livelihoods, and properties.

Help your readers prepare for disasters in an informative essay. List what should be done before, during, and after a volcanic eruption. Include relevant tips such as being observant to know where possible emergency shelters are. You can also add any assistance offered by the government to support the victims.Here’s a great tip: Proper grammar is critical for your essays. Grammarly is one of our top grammar checkers. Find out why in this  Grammarly review .

Maria Caballero is a freelance writer who has been writing since high school. She believes that to be a writer doesn't only refer to excellent syntax and semantics but also knowing how to weave words together to communicate to any reader effectively.

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Volcanic Eruptions and Their Repose, Unrest, Precursors, and Timing (2017)

Chapter: 1 introduction, 1 introduction.

Volcanoes are a key part of the Earth system. Most of Earth’s atmosphere, water, and crust were delivered by volcanoes, and volcanoes continue to recycle earth materials. Volcanic eruptions are common. More than a dozen are usually erupting at any time somewhere on Earth, and close to 100 erupt in any year ( Loughlin et al., 2015 ).

Volcano landforms and eruptive behavior are diverse, reflecting the large number and complexity of interacting processes that govern the generation, storage, ascent, and eruption of magmas. Eruptions are influenced by the tectonic setting, the properties of Earth’s crust, and the history of the volcano. Yet, despite the great variability in the ways volcanoes erupt, eruptions are all governed by a common set of physical and chemical processes. Understanding how volcanoes form, how they erupt, and their consequences requires an understanding of the processes that cause rocks to melt and change composition, how magma is stored in the crust and then rises to the surface, and the interaction of magma with its surroundings. Our understanding of how volcanoes work and their consequences is also shared with the millions of people who visit U.S. volcano national parks each year.

Volcanoes have enormous destructive power. Eruptions can change weather patterns, disrupt climate, and cause widespread human suffering and, in the past, mass extinctions. Globally, volcanic eruptions caused about 80,000 deaths during the 20th century ( Sigurdsson et al., 2015 ). Even modest eruptions, such as the 2010 Eyjafjallajökull eruption in Iceland, have multibillion-dollar global impacts through disruption of air traffic. The 2014 steam explosion at Mount Ontake, Japan, killed 57 people without any magma reaching the surface. Many volcanoes in the United States have the potential for much larger eruptions, such as the 1912 eruption of Katmai, Alaska, the largest volcanic eruption of the 20th century ( Hildreth and Fierstein, 2012 ). The 2008 eruption of the unmonitored Kasatochi volcano, Alaska, distributed volcanic gases over most of the continental United States within a week ( Figure 1.1 ).

Finally, volcanoes are important economically. Volcanic heat provides low-carbon geothermal energy. U.S. generation of geothermal energy accounts for nearly one-quarter of the global capacity ( Bertani, 2015 ). In addition, volcanoes act as magmatic and hydrothermal distilleries that create ore deposits, including gold and copper ores.

Moderate to large volcanic eruptions are infrequent yet high-consequence events. The impact of the largest possible eruption, similar to the super-eruptions at Yellowstone, Wyoming; Long Valley, California; or Valles Caldera, New Mexico, would exceed that of any other terrestrial natural event. Volcanoes pose the greatest natural hazard over time scales of several decades and longer, and at longer time scales they have the potential for global catastrophe ( Figure 1.2 ). While

the continental United States has not suffered a fatal eruption since 1980 at Mount St. Helens, the threat has only increased as more people move into volcanic areas.

Volcanic eruptions evolve over very different temporal and spatial scales than most other natural hazards ( Figure 1.3 ). In particular, many eruptions are preceded by signs of unrest that can serve as warnings, and an eruption itself often persists for an extended period of time. For example, the eruption of Kilauea Volcano in Hawaii has continued since 1983. We also know the locations of many volcanoes and, hence, where most eruptions will occur. For these reasons, the impacts of at least some types of volcanic eruptions should be easier to mitigate than other natural hazards.

Anticipating the largest volcanic eruptions is possible. Magma must rise to Earth’s surface and this movement is usually accompanied by precursors—changes in seismic, deformation, and geochemical signals that can be recorded by ground-based and space-borne instruments. However, depending on the monitoring infrastructure, precursors may present themselves over time scales that range from a few hours (e.g., 2002 Reventador, Ecuador, and 2015 Calbuco, Chile) to decades before eruption (e.g., 1994 Rabaul, Papua New Guinea). Moreover, not all signals of volcanic unrest are immediate precursors to surface eruptions (e.g., currently Long Valley, California, and Campi Flegrei, Italy).

Probabilistic forecasts account for this uncertainty using all potential eruption scenarios and all relevant data. An important consideration is that the historical record is short and biased. The instrumented record is even shorter and, for most volcanoes, spans only the last few decades—a miniscule fraction of their lifetime. Knowledge can be extended qualitatively using field studies of volcanic deposits, historical accounts, and proxy data, such as ice and marine sediment cores and speleothem (cave) records. Yet, these too are biased because they commonly do not record small to moderate eruptions.

Understanding volcanic eruptions requires contributions from a wide range of disciplines and approaches. Geologic studies play a critical role in reconstructing the past eruption history of volcanoes,

especially of the largest events, and in regions with no historical or directly observed eruptions. Geochemical and geophysical techniques are used to study volcano processes at scales ranging from crystals to plumes of volcanic ash. Models reveal essential processes that control volcanic eruptions, and guide data collection. Monitoring provides a wealth of information about the life cycle of volcanoes and vital clues about what kind of eruption is likely and when it may occur.

1.1 OVERVIEW OF THIS REPORT

At the request of managers at the National Aeronautics and Space Administration (NASA), the National Science Foundation, and the U.S. Geological Survey (USGS), the National Academies of Sciences, Engineering, and Medicine established a committee to undertake the following tasks:

• Summarize current understanding of how magma is stored, ascends, and erupts.
• Discuss new disciplinary and interdisciplinary research on volcanic processes and precursors that could lead to forecasts of the type, size, and timing of volcanic eruptions.
• Describe new observations or instrument deployment strategies that could improve quantification of volcanic eruption processes and precursors.
• Identify priority research and observations needed to improve understanding of volcanic eruptions and to inform monitoring and early warning efforts.

The roles of the three agencies in advancing volcano science are summarized in Box 1.1 .

The committee held four meetings, including an international workshop, to gather information, deliberate, and prepare its report. The report is not intended to be a comprehensive review, but rather to provide a broad overview of the topics listed above. Chapter 2 addresses the opportunities for better understanding the storage, ascent, and eruption of magmas. Chapter 3 summarizes the challenges and prospects for forecasting eruptions and their consequences. Chapter 4 highlights repercussions of volcanic eruptions on a host of other Earth systems. Although not explicitly called out in the four tasks, the interactions between volcanoes and other Earth systems affect the consequences of eruptions, and offer opportunities to improve forecasting and obtain new insights into volcanic processes. Chapter 5 summarizes opportunities to strengthen

research in volcano science. Chapter 6 provides overarching conclusions. Supporting material appears in appendixes, including a list of volcano databases (see Appendix A ), a list of workshop participants (see Appendix B ), biographical sketches of the committee members (see Appendix C ), and a list of acronyms and abbreviations (see Appendix D ).

Background information on these topics is summarized in the rest of this chapter.

1.2 VOLCANOES IN THE UNITED STATES

The USGS has identified 169 potentially active volcanoes in the United States and its territories (e.g., Marianas), 55 of which pose a high threat or very high threat ( Ewert et al., 2005 ). Of the total, 84 are monitored by at least one seismometer, and only 3 have gas sensors (as of November 2016). 1 Volcanoes are found in the Cascade mountains, Aleutian arc, Hawaii, and the western interior of the continental United States ( Figure 1.4 ). The geographical extent and eruption hazards of these volcanoes are summarized below.

The Cascade volcanoes extend from Lassen Peak in northern California to Mount Meager in British Columbia. The historical record contains only small- to moderate-sized eruptions, but the geologic record reveals much larger eruptions ( Carey et al., 1995 ; Hildreth, 2007 ). Activity tends to be sporadic ( Figure 1.5 ). For example, nine Cascade eruptions occurred in the 1850s, but none occurred between 1915 and 1980, when Mount St. Helens erupted. Consequently, forecasting eruptions in the Cascades is subject to considerable uncertainty. Over the coming decades, there may be multiple eruptions from several volcanoes or no eruptions at all.

The Aleutian arc extends 2,500 km across the North Pacific and comprises more than 130 active and potentially active volcanoes. Although remote, these volcanoes pose a high risk to overflying aircraft that carry more than 30,000 passengers a day, and are monitored by a combination of ground- and space-based sensors. One or two small to moderate explosive eruptions occur in the Aleutians every year, and very large eruptions occur less frequently. For example, the world’s largest eruption of the 20th century occurred approximately 300 miles from Anchorage, in 1912.

In Hawaii, Kilauea has been erupting largely effusively since 1983, but the location and nature of eruptions can vary dramatically, presenting challenges for disaster preparation. The population at risk from large-volume, rapidly moving lava flows on the flanks of the Mauna Loa volcano has grown tremendously in the past few decades ( Dietterich and Cashman, 2014 ), and few island residents are prepared for the even larger magnitude explosive eruptions that are documented in the last 500 years ( Swanson et al., 2014 ).

All western states have potentially active volcanoes, from New Mexico, where lava flows have reached within a few kilometers of the Texas and Oklahoma borders ( Fitton et al., 1991 ), to Montana, which borders the Yellowstone caldera ( Christiansen, 1984 ). These volcanoes range from immense calderas that formed from super-eruptions ( Mastin et al., 2014 ) to small-volume basaltic volcanic fields that erupt lava flows and tephra for a few months to a few decades. Some of these eruptions are monogenic (erupt just once) and pose a special challenge for forecasting. Rates of activity in these distributed volcanic fields are low, with many eruptions during the past few thousand years (e.g., Dunbar, 1999 ; Fenton, 2012 ; Laughlin et al., 1994 ), but none during the past hundred years.

1.3 THE STRUCTURE OF A VOLCANO

Volcanoes often form prominent landforms, with imposing peaks that tower above the surrounding landscape, large depressions (calderas), or volcanic fields with numerous dispersed cinder cones, shield volcanoes, domes, and lava flows. These various landforms reflect the plate tectonic setting, the ways in which those volcanoes erupt, and the number of eruptions. Volcanic landforms change continuously through the interplay between constructive processes such as eruption and intrusion, and modification by tectonics, climate, and erosion. The stratigraphic and structural architecture of volcanoes yields critical information on eruption history and processes that operate within the volcano.

Beneath the volcano lies a magmatic system that in most cases extends through the crust, except during eruption. Depending on the setting, magmas may rise

___________________

1 Personal communication from Charles Mandeville, Program Coordinator, Volcano Hazards Program, U.S. Geological Survey, on November 26, 2016.

directly from the mantle or be staged in one or more storage regions within the crust before erupting. The uppermost part (within 2–3 km of Earth’s surface) often hosts an active hydrothermal system where meteoric groundwater mingles with magmatic volatiles and is heated by deeper magma. Identifying the extent and vigor of hydrothermal activity is important for three reasons: (1) much of the unrest at volcanoes occurs in hydrothermal systems, and understanding the interaction of hydrothermal and magmatic systems is important for forecasting; (2) pressure buildup can cause sudden and potentially deadly phreatic explosions from the hydrothermal system itself (such as on Ontake, Japan, in 2014), which, in turn, can influence the deeper magmatic system; and (3) hydrothermal systems are energy resources and create ore deposits.

Below the hydrothermal system lies a magma reservoir where magma accumulates and evolves prior to eruption. Although traditionally modeled as a fluid-filled cavity, there is growing evidence that magma reservoirs may comprise an interconnected complex of vertical and/or horizontal magma-filled cracks, or a partially molten mush zone, or interleaved lenses of magma and solid material ( Cashman and Giordano, 2014 ). In arc volcanoes, magma chambers are typically located 3–6 km below the surface. The magma chamber is usually connected to the surface via a fluid-filled conduit only during eruptions. In some settings, magma may ascend directly from the mantle without being stored in the crust.

In the broadest sense, long-lived magma reservoirs comprise both eruptible magma (often assumed to contain less than about 50 percent crystals) and an accumulation of crystals that grow along the margins or settle to the bottom of the magma chamber. Physical segregation of dense crystals and metals can cause the floor of the magma chamber to sag, a process balanced by upward migration of more buoyant melt. A long-lived magma chamber can thus become increasingly stratified in composition and density.

The deepest structure beneath volcanoes is less well constrained. Swarms of low-frequency earthquakes at mid- to lower-crustal depths (10–40 km) beneath volcanoes suggest that fluid is periodically transferred into the base of the crust ( Power et al., 2004 ). Tomographic studies reveal that active volcanic systems have deep crustal roots that contain, on average, a small fraction of melt, typically less than 10 percent. The spatial distribution of that melt fraction, particularly how much is concentrated in lenses or in larger magma bodies, is unknown. Erupted samples preserve petrologic and geochemical evidence of deep crystallization, which requires some degree of melt accumulation. Seismic imaging and sparse outcrops suggest that the proportion of unerupted solidified magma relative to the surrounding country rock increases with depth and that the deep roots of volcanoes are much more extensive than their surface expression.

1.4 MONITORING VOLCANOES

Volcano monitoring is critical for hazard forecasts, eruption forecasts, and risk mitigation. However, many volcanoes are not monitored at all, and others are monitored using only a few types of instruments. Some parameters, such as the mass, extent, and trajectory of a volcanic ash cloud, are more effectively measured by satellites. Other parameters, notably low-magnitude earthquakes and volcanic gas emissions that may signal an impending eruption, require ground-based monitoring on or close to the volcanic edifice. This section summarizes existing and emerging technologies for monitoring volcanoes from the ground and from space.

Monitoring Volcanoes on or Near the Ground

Ground-based monitoring provides data on the location and movement of magma. To adequately capture what is happening inside a volcano, it is necessary to obtain a long-term and continuous record, with periods spanning both volcanic quiescence and periods of unrest. High-frequency data sampling and efficient near-real-time relay of information are important, especially when processes within the volcano–magmatic–hydrothermal system are changing rapidly. Many ground-based field campaigns are time intensive and can be hazardous when volcanoes are active. In these situations, telemetry systems permit the safe and continuous collection of data, although the conditions can be harsh and the lifetime of instruments can be limited in these conditions.

Ground-based volcano monitoring falls into four broad categories: seismic, deformation, gas, and thermal monitoring ( Table 1.1 ). Seismic monitoring tools,

TABLE 1.1 Ground-Based Instrumentation for Monitoring Volcanoes

including seismometers and infrasound sensors, are used to detect vibrations caused by breakage of rock and movement of fluids and to assess the evolution of eruptive activity. Ambient seismic noise monitoring can image subsurface reservoirs and document changes in wave speed that may reflect stress. changes. Deformation monitoring tools, including tiltmeters, borehole strainmeters, the Global Navigation Satellite System (GNSS, which includes the Global Positioning System [GPS]), lidar, radar, and gravimeters, are used to detect the motion of magma and other fluids in the subsurface. Some of these tools, such as GNSS and lidar, are also used to detect erupted products, including ash clouds, pyroclastic density currents, and volcanic bombs. Gas monitoring tools, including a range of sensors ( Table 1.1 ), and direct sampling of gases and fluids are used to detect magma intrusions and changes in magma–hydrothermal interactions. Thermal monitoring tools, such as infrared cameras, are used to detect dome growth and lava breakouts. Continuous video or photographic observations are also commonly used and, despite their simplicity, most directly document volcanic activity. Less commonly used monitoring technologies, such as self-potential, electromagnetic techniques, and lightning detection are used to constrain fluid movement and to detect

ash clouds. In addition, unmanned aerial vehicles (e.g., aircraft and drones) are increasingly being used to collect data. Rapid sample collection and analysis is also becoming more common as a monitoring tool at volcano observatories. A schematic of ground-based monitoring techniques is shown in Figure 1.6 .

Monitoring Volcanoes from Space

Satellite-borne sensors and instruments provide synoptic observations during volcanic eruptions when collecting data from the ground is too hazardous or where volcanoes are too remote for regular observation. Repeat-pass data collected over years or decades provide a powerful means for detecting surface changes on active volcanoes. Improvements in instrument sensitivity, data availability, and the computational capacity required to process large volumes of data have led to a dramatic increase in “satellite volcano science.”

Although no satellite-borne sensor currently in orbit has been specifically designed for volcano monitoring, a number of sensors measure volcano-relevant

TABLE 1.2 Satellite-Borne Sensor Suite for Volcano Monitoring

NOTE: AIRS, Atmospheric Infrared Sounder; ALOS, Advanced Land Observing Satellite; ASTER, Advanced Spaceborne Thermal Emission and Reflection Radiometer; AVHRR, Advanced Very High Resolution Radiometer; CALIPSO, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation; COSMO-SkyMed, Constellation of Small Satellites for Mediterranean Basin Observation; GOES, Geostationary Operational Environmental Satellite; IASI, Infrared Atmospheric Sounding Interferometer; MISR, Multi-angle Imaging SpectroRadiometer; MLS, Microwave Limb Sounder; MODIS, Moderate Resolution Imaging Spectroradiometer; OMI, Ozone Monitoring Instrument; OMPS, Ozone Mapping and Profiler Suite; SAGE, Stratospheric Aerosol and Gas Experiment.

parameters, including heat flux, gas and ash emissions, and deformation ( Table 1.2 ). Thermal infrared data are used to detect eruption onset and cessation, calculate lava effusion rates, map lava flows, and estimate ash column heights during explosive eruptions. In some cases, satellites may capture thermal precursors to eruptions, although low-temperature phenomena are challenging to detect. Both high-temporal/low-spatial-resolution (geostationary orbit) and high-spatial/low-temporal-resolution (polar orbit) thermal infrared observations are needed for global volcano monitoring.

Satellite-borne sensors are particularly effective for observing the emission and dispersion of volcanic gas and ash plumes in the atmosphere. Although several volcanic gas species can be detected from space (including SO 2 , BrO, OClO, H 2 S, HCl, and CO; Carn et al., 2016 ), SO 2 is the most readily measured, and it is also responsible for much of the impact of eruptions on climate. Satellite measurements of SO 2 are valuable for detecting eruptions, estimating global volcanic fluxes and recycling of other volatile species, and tracking volcanic clouds that may be hazardous to aviation in near real time. Volcanic ash cloud altitude is most accurately determined by spaceborne lidar, although spatial coverage is limited. Techniques for measuring volcanic CO 2 from space are under development and could lead to earlier detection of preeruptive volcanic degassing.

Interferometric synthetic aperture radar (InSAR) enables global-scale background monitoring of volcano deformation ( Figure 1.7 ). InSAR provides much higher spatial resolution than GPS, but lower accuracy and temporal resolution. However, orbit repeat times will diminish as more InSAR missions are launched, such as the European Space Agency’s recently deployed Sentinel-1 satellite and the NASA–Indian Space Research Organisation synthetic aperture radar mission planned for launch in 2020.

1.5 ERUPTION BEHAVIOR

Eruptions range from violently explosive to gently effusive, from short lived (hours to days) to persistent over decades or centuries, from sustained to intermittent, and from steady to unsteady ( Siebert et al., 2015 ). Eruptions may initiate from processes within the magmatic system ( Section 1.3 ) or be triggered by processes and properties external to the volcano, such as precipitation, landslides, and earthquakes. The eruption behavior of a volcano may change over time. No classification scheme captures this full diversity of behaviors (see Bonadonna et al., 2016 ), but some common schemes to describe the style, magnitude, and intensity of eruptions are summarized below.

Eruption Magnitude and Intensity

The size of eruptions is usually described in terms of total erupted mass (or volume), often referred to as magnitude, and mass eruption rate, often referred to as intensity. Pyle (2015) quantified magnitude and eruption intensity as follows:

magnitude = log 10 (mass, in kg) – 7, and

intensity = log 10 (mass eruption rate, in kg/s) + 3.

The Volcano Explosivity Index (VEI) introduced by Newhall and Self (1982) assigns eruptions to a VEI class based primarily on measures of either magnitude (erupted mass or volume) or intensity (mass eruption rate and/or eruption plume height), with more weight given to magnitude. The VEI classes are summarized in Figure 1.8 . The VEI classification is still in use, despite its many limitations, such as its reliance on only a few types of measurements and its poor fit for small to moderate eruptions (see Bonadonna et al., 2016 ).

Smaller VEI events are relatively common, whereas larger VEI events are exponentially less frequent ( Siebert et al., 2015 ). For example, on average about three VEI 3 eruptions occur each year, whereas there is a 5 percent chance of a VEI 5 eruption and a 0.2 percent chance of a VEI 7 (e.g., Crater Lake, Oregon) event in any year.

Eruption Style

The style of an eruption encompasses factors such as eruption duration and steadiness, magnitude, gas flux, fountain or column height, and involvement of magma and/or external source of water (phreatic and phreatomagmatic eruptions). Eruptions are first divided into effusive (lava producing) and explosive (pyroclast producing) styles, although individual eruptions can be simultaneously effusive and weakly explosive, and can pass rapidly and repeatedly between eruption styles. Explosive eruptions are further subdivided into styles that are sustained on time scales of hours to days and styles that are short lived ( Table 1.3 ).

Classification of eruption style is often qualitative and based on historical accounts of characteristic eruptions from type-volcanoes. However, many type-volcanoes exhibit a range of eruption styles over time (e.g., progressing between Strombolian, Vulcanian, and Plinian behavior; see Fee et al., 2010 ), which has given rise to terms such as subplinian or violent Strombolian.

1.6 ERUPTION HAZARDS

Eruption hazards are diverse ( Figure 1.9 ) and may extend more than thousands of kilometers from an active volcano. From the perspective of risk and impact, it is useful to distinguish between near-source and distal hazards. Near-source hazards are far more unpredictable than distal hazards.

Near-source hazards include those that are airborne, such as tephra fallout, volcanic gases, and volcanic projectiles, and those that are transported laterally on or near the ground surface, such as pyroclastic density currents, lava flows, and lahars. Pyroclastic density currents are hot volcanic flows containing mixtures of gas and micron- to meter-sized volcanic particles. They can travel at velocities exceeding 100 km per hour. The heat combined with the high density of material within these flows obliterates objects in their path, making them the most destructive of volcanic hazards. Lava flows also destroy everything in their path, but usually move slowly enough to allow people to get out of the way. Lahars are mixtures of volcanic debris, sediment, and water that can travel many tens of kilometers along valleys and river channels. They may be triggered during an eruption by interaction between volcanic prod-

TABLE 1.3 Characteristics of Different Eruption Styles

ucts and snow, ice, rain, or groundwater. Lahars can be more devastating than the eruption itself. Ballistic blocks are large projectiles that typically fall within 1–5 km from vents.

The largest eruptions create distal hazards. Explosive eruptions produce plumes that are capable of dispersing ash hundreds to thousands of kilometers from the volcano. The thickness of ash deposited depends on the intensity and duration of the eruption and the wind direction. Airborne ash and ash fall are the most severe distal hazards and are likely to affect many more people than near-source hazards. They cause respiratory problems and roof collapse, and also affect transport networks and infrastructure needed to support emergency response. Volcanic ash is a serious risk to air traffic. Several jets fully loaded with passengers have temporarily lost power on all engines after encountering dilute ash clouds (e.g., Guffanti et al., 2010 ). Large lava flows, such as the 1783 Laki eruption in Iceland, emit volcanic gases that create respiratory problems and acidic rain more than 1,000 km from the eruption. Observed impacts of basaltic eruptions in Hawaii and Iceland include regional volcanic haze (“vog”) and acid rain that affect both agriculture and human health (e.g., Thordarson and Self, 2003 ) and fluorine can contaminate grazing land and water supplies (e.g., Cronin et al., 2003 ). Diffuse degassing of CO 2 can lead to deadly concentrations with fatal consequences such as occurred at Mammoth Lakes, California, or cause lakes to erupt, leading to massive CO 2 releases that suffocate people (e.g., Lake Nyos, Cameroon).

Secondary hazards can be more devastating than the initial eruption. Examples include lahars initiated by storms, earthquakes, landslides, and tsunamis from eruptions or flank collapse; volcanic ash remobilized by wind to affect human health and aviation for extended periods of time; and flooding because rain can no longer infiltrate the ground.

1.7 MODELING VOLCANIC ERUPTIONS

Volcanic processes are governed by the laws of mass, momentum, and energy conservation. It is possible to develop models for magmatic and volcanic phenomena based on these laws, given sufficient information on mechanical and thermodynamic properties of the different components and how they interact with each other. Models are being developed for all processes in volcanic systems, including melt transport in the mantle, the evolution of magma bodies within the crust, the ascent of magmas to the surface, and the fate of magma that erupts effusively or explosively.

A central challenge for developing models is that volcanic eruptions are complex multiphase and multicomponent systems that involve interacting processes over a wide range of length and time scales. For example, during storage and ascent, the composition, temperature, and physical properties of magma and host rocks evolve. Bubbles and crystals nucleate and grow in this magma and, in turn, greatly influence the properties of the magmas and lavas. In explosive eruptions, magma fragmentation creates a hot mixture of gas and particles with a wide range of sizes and densities. Magma also interacts with its surroundings: the deformable rocks that surround the magma chamber and conduit, the potentially volatile groundwater and surface water, a changing landscape over which pyroclastic density currents and lava flows travel, and the atmosphere through which eruption columns rise.

Models for volcanic phenomena that involve a small number of processes and that are relatively amenable to direct observation, such as volcanic plumes, are relatively straightforward to develop and test. In contrast, phenomena that occur underground are more difficult to model because there are more interacting processes. In those cases, direct validation is much more challenging and in many cases impossible. Forecasting ash dispersal using plume models is more straightforward and testable than forecasting the onset, duration, and style of eruption using models that seek to explain geophysical and geochemical precursors. In all cases, however, the use of even imperfect models helps improve the understanding of volcanic systems.

Modeling approaches can be divided into three categories:

• Reduced models make simplifying assumptions about dynamics, heat transfer, and geometry to develop first-order explanations for key properties and processes, such as the velocity of lava flows and pyroclastic density currents, the height of eruption columns, the magma chamber size and depth, the dispersal of tephra, and the ascent of magma in conduits. Well-calibrated or tested reduced models offer a straightforward ap-

proach for combining observations and models in real time in an operational setting (e.g., ash dispersal forecasting for aviation safety). Models may not need to be complex if they capture the most important processes, although simplifications require testing against more comprehensive models and observations.

• Multiphase and multiphysics models improve scientific understanding of complex processes by invoking fewer assumptions and idealizations than reduced models ( Figure 1.10 ), but at the expense of increased complexity and computational demands. They also require additional components, such as a model for how magma in magma chambers and conduits deforms when stressed; a model for turbulence in pyroclastic density currents and plumes; terms that describe the thermal and mechanical exchange among gases, crystals, and particles; and a description of ash aggregation in eruption columns. A central challenge for multiphysics models is integrating small-scale processes with large-scale dynamics. Many of the models used in volcano science build on understanding developed in other science and engineering fields and for other ap-

plications. Multiphysics and multiscale models benefit from rapidly expanding computational capabilities.

• Laboratory experiments simulate processes for which the geometry and physical and thermal processes and properties can be scaled ( Mader et al., 2004 ). Such experiments provide insights on fundamental processes, such as crystal dynamics in flowing magmas, entrainment in eruption columns, propagation of dikes, and sedimentation from pyroclastic density currents ( Figure 1.11 ). Experiments have also been used successfully to develop the subsystem models used in numerical simulations, and to validate computer simulations for known inputs and properties.

The great diversity of existing models reflects to a large extent the many interacting processes that operate in volcanic eruptions and the corresponding simplifying assumptions currently required to construct such models. The challenge in developing models is often highlighted in discrepancies between models and observations of natural systems. Nevertheless, eruption models reveal essential processes governing volcanic eruptions, and they provide a basis for interpreting measurements from prehistoric and active eruptions and for closing observational gaps. Mathematical models offer a guide for what observations will be most useful. They may also be used to make quantitative and testable predictions, supporting forecasting and hazard assessment.

Volcanic eruptions are common, with more than 50 volcanic eruptions in the United States alone in the past 31 years. These eruptions can have devastating economic and social consequences, even at great distances from the volcano. Fortunately many eruptions are preceded by unrest that can be detected using ground, airborne, and spaceborne instruments. Data from these instruments, combined with basic understanding of how volcanoes work, form the basis for forecasting eruptions—where, when, how big, how long, and the consequences.

Accurate forecasts of the likelihood and magnitude of an eruption in a specified timeframe are rooted in a scientific understanding of the processes that govern the storage, ascent, and eruption of magma. Yet our understanding of volcanic systems is incomplete and biased by the limited number of volcanoes and eruption styles observed with advanced instrumentation. Volcanic Eruptions and Their Repose, Unrest, Precursors, and Timing identifies key science questions, research and observation priorities, and approaches for building a volcano science community capable of tackling them. This report presents goals for making major advances in volcano science.

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100 Words Essay On Volcanic Eruptions In English

Wikipedia defines the term as follows: “A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.” A volcanic eruption is when lava and gas are released from a volcano—sometimes explosively. 

In layman’s terms, it is a natural calamity that leads to dire consequences including loss of life and property. Indonesia is the most prone to volcanic eruptions in the world and is known as the ‘Pacific Ring of Fire’. Its 1815 eruption of Mount Tambora is the most powerful in history. 

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Essay, Paragraph or Speech on “Volcanoes” Complete English Essay, Speech for Class 10, Class 12 and Graduation and other classes.

Volcano is a natural occurrence that takes place from a mountain with a large opening at the top. Volcanic eruptions have always sat life-threatening situations and death traps for civilizations all over the world. The study of volcanoes is known as ‘volcanology’.

A volcano is an opening in the surface of the earth. This opening allows hot magma, volcanic ash and gases to escape from below the surface. Magma is a very hot liquid rock found below the earth’s surface. When this happens, we say that the volcano has erupted.

When molten rock is below the surface of the earth, it is called ‘magma’. After it erupts from an opening, it is called lava’. Lava is red-hot when it fires out. The rising lava contains crystals, dissolved gases and solid pieces of rocks. Mostly this liquid is made up it oxygen, silicon, aluminium, iron, magnesium, calcium, sodium, potassium and manganese.

When an eruption takes place, it explodes into the air and the molten rock forces its way out. The lava starts flowing, destroying everything that comes in its path. Thick, dark clouds of smoke rise high from the opening and spread in the sky. Even finer dust particles, mud and ash are thrown high into the air. As the lava cools, it slowly becomes solid. Its colour changes into a black, dark grey or even red.

Volcanoes are popularly classified into three categories. They are active volcanoes, dormant volcanoes and extinct volcanoes. Those volcanoes that erupt frequently are called ‘active volcanoes’. Krakatoa is an active volcano in the island in the Sunda Strait between Java and Sumatra in Indonesia. It has erupted several times causing tremendous disasters. The worst of the eruption took place in 1883. Those volcanoes that have erupted in early times but are now quiet are called ‘dormant volcanoes’. They are also called as ‘sleeping volcanoes’. They stay silent for long time and abruptly erupt violently causing massive destruction to life and property. Vesuvius in Italy and Katmai in Alaska are the examples of dormant volcanoes. Information about the eruption of such volcanoes is found in history. Volcanoes that have not erupted for thousands of years are considered as ‘extinct volcanoes’. As they do not show any indication of future eruption, they are also known as ‘dead volcanoes’. Mount Kilimanjaro in Tanzania in the continent of Africa is an example of extinct volcano. By looking at the formation of the rock, geographers can guess that they erupted long ago. However, there is no record of it in history.

Scientists usually, expect a volcanic erupting if the signs of unrest such as earthquakes are seen. The life of a volcano can vary from months to several million years. Many volcanoes have erupted in past few thousand years but are currently not showing any signs of eruption.

( 460 Words )

A volcano is an opening, in the planet’s surface which allows hot, molten rock, ash and gases to escape from below the surface. The name, “volcano” originates from the name Vulcan, a god of fire in Roman mythology. Volcanoes are like giant safety valves that release the pressure that builds up inside the Earth. The Hawaii islands were formed by 5 volcanoes. Classified by the extent of their activity volcanoes are of four types. An ‘active’ volcano is one that erupts regularly. There are about 500 known active volcanoes on Earth, not counting those that lie beneath the sea. A ‘dormant’ volcano is one that has not erupted for many years, although there is still some activity deep inside it. An ‘extinct’ volcano is one which has ceased to be active.

A volcanic eruption occurs when hot rocks and lava burst from a volcano; and geysers and springs are actually just volcanoes that throw boiling water high in the air. They are caused by volcanic heat warming trapped ground water. The liquid rocks inside a volcano are called magma and when it flows out it is called as lava. Fresh lava has temperatures from 700 degrees C to 1200’C and glows red-hot to white hot as it flows. The most dangerous volcanic eruption recorded is the eruption of Mount St. Helens in Washington. The tallest volcano in the world is the Ojos del Salado, a volcano in Chile. The world’s largest volcano is the Muano Loa in Hawaii.

Volcanoes are generally concentrated on the edge of continents, along the island chain, or beneath the sea forming long mountain ranges. A major part of the world’s active volcanoes above sea level encircle the Pacific Ocean forming the “Ring of Fire.” Volcanoes can have serious effects on the lands and people around them when they erupt. The destruction they leave in their wake accounts for the total annihilation of the surrounding landscape. Around 2,00,000 people have lost their lives to volcanic eruptions in the past five hundred years. Buildings are destroyed, people are rendered homeless, people are killed, plant and animal life are both destroyed and the poisonous gases that emanate from the volcanoes can cause death and diseases like pneumonia in the people who survive it.

However not everything associated with the volcanoes is negative. The crust of the earth exists due to the large volumes of magma that did not erupt but instead cooled below the surface. It results in rich soil which is good for cultivation. The volcanic ash that blows out of the volcano increases soil fertility by adding nutrients to the soil. Ground water heated by magma can be tapped for geothermal energy. Most of the metallic minerals like copper, gold, silver, lead and zinc are mined from the magmas found deep within the roots of extinct volcanoes.

With the increasing studies done by scientists on volcanoes it is becoming possible to gauge the activity level of a volcano. With this information although it might not be possible to prevent the erupting of a volcano at least the massive destruction of lives can be avoided by getting people evacuated in time.

( 600 Words )

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• Earth Science

Volcano Eruption

Volcanoes are ruptures in the crust of our planet Earth that allow hot gases, molten lava and some rock fragments to erupt by opening and exposing the magma inside. In this piece of article, we will be discussing how and why volcanoes erupt.

How Do Volcanoes Erupt?

It is so hot deep within the earth that some rocks slowly melt and turn into a thick flowing matter known as magma. Since it is lighter than solid rock, the magma rises and collects in magma chambers. Eventually, some magma pushes through fissures and vents on the earth’s surface. Hence, a volcanic eruption occurs, and the erupted magma is known as lava.

We need to understand the Earth’s structure to know how volcanoes erupt. At the top lies the lithosphere, the outermost layer that consists of the upper crust and mantle. The thickness of the crust ranges from 10km to 100km in mountainous locations and mainly consists of silicate rock.

See the video below to know more about the causes of volcanic eruptions.

Why Do Volcanoes Erupt?

The Earth’s mantle within the crust is classified into different sections depending on individual seismology. These include the upper mantle, which ranges between 8 – 35 km to 410 km; the transition zone ranges from 400 to 660 km; the lower mantle lies between 660 – 2891 km.

The conditions change dramatically from the crust to the mantle location. The pressures rise drastically and temperatures rise up to 1000 o C. This viscous and molten rock gets collected into large chambers within the Earth’s crust.

Since magma is lighter than surrounding rock, it floats up towards the surface and seeks out cracks and weakness in the mantle. It finally explodes from the peak point of a volcano after reaching the surface. When it is under the surface, the melted rock is known as magma and erupts as ash when comes up.

Rocks, lava and ash are built across the volcanic vent with every eruption. The nature of the eruption mainly depends on the viscosity of the magma. The lava travels far and generates broad shield volcanoes when it flows easily. When it is too thick, it makes a familiar cone volcano shape. If the lava is extremely thick, it can build up in the volcano and explode, known as lava domes.

Causes of Volcanic Eruption

We know that the mantle of the Earth is too hot, and the temperature ranges from 1000° Celsius to 3000° Celsius. The rocks present inside melt due to high pressure and temperature. The melted substance is light in weight. This thin lava comes up to the crust since it can float easily. Since the density of the magma between the area of its creation and the crust is less than the enclosed rocks, the magma gets to the surface and bursts. The magma is composed of andesitic and rhyolitic components along with water, sulfur dioxide, and carbon dioxide in dissolved form. By forming bubbles, excess water is broken up with magma. When the magma comes closer to the surface, the level of water decreases and the gas/magma rises in the channel. When the volume of the bubbles formed is about 75%, the magma breaks into pyroclasts and bursts out. The three main causes of volcanic eruptions are: The buoyancy of the magma Pressure from the exsolved gases in the magma Increase in pressure on the chamber lid Hope you are familiar with why volcanoes erupt and the cause of the volcanic eruption. Stay tuned to BYJU’S to learn about types of volcanoes, igneous rocks, and much more.

Frequently Asked Questions – FAQs

What is lava.

When a volcanic eruption occurs, the erupted magma is known as lava.

State true or false: The nature of the eruption mainly depends on the viscosity of the magma.

What are the causes of volcanic eruption.

The causes of the volcanic eruption are:

• The buoyancy of the magma
• Pressure from the dissolved gases in the magma
• Increase in pressure on the chamber lid

Define magma.

How is earth’s mantle classified.

• The upper mantle – ranges between 8 – 35 km to 410 km
• Transition zone ranges from 400 to 660 km
• Lower mantle lies between 660 – 2891 km

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Deep Sea Volcanoes and their Effects Research Paper

Absorption of carbon dioxide, rising temperatures and melting ice caps, marine life.

The ocean floor is comprised of many hills, mountains, valleys, volcanoes and certain forms of life, easily unimagined to the common man.The entire global ocean floor is approximately 366 million square kilometers and the entire surface area is a volcanic terrain (Fisher, 1998, p. 81). Of the entire ocean floor, there are about a million deep sea volcanoes. Approximately 75,000 of them rise over a kilometer above the ocean floor. The number of active volcanoes is however not determined but it is projected to be in thousands.

Deep sea volcanic eruptions are quite prevalent than is otherwise known. In fact, about 4 cubic kilometers of volcanic lava is erupted annually according to estimations developed from the movement of the earth’s tectonic plates (Fisher, 1998, p. 82). Most of these eruptions are however not seen on the earth’s surface but they are often observed when ridges stretch into dry land.

Oceanographers have in the past carried out research to better understand the ocean’s volcanic terrain. However, their conclusions have not been comprehensive enough; especially with regard to the effects of deep sea volcanic eruptions on the environment. This study therefore explores the relation between deep sea volcanic activities and the environment, with specific reference to existing myths on global warming, an emphasis on marine life, general climatic conditions and topographical effects.

Not all volcanoes are a menace to the environment because of their toxic gases and molten lava. The effects of volcanoes are varied and may even result in the development of lahars. For instance, in September 1996, an undersea volcano with a magnitude of five on the Richter scale shook the Southeastern part of Iceland.

A month later, a deep basin formed on the glacier. Subsequent glaciers were also observed on the same zone (Patricia, 1999, p. 201). This indicated that melting was going on underneath the glacier and generally, the effects of deep sea volcanic activities go beyond toxic gases and molten lava.

The impacts of deep sea volcanoes are therefore varied, and the predictability of a volcano erupting is as difficult as predicting an earthquake (Patricia, 1999, p. 201). However, scientists at present use various parameters and devices to predict volcanic activity such as seismicity (which is also used to predict earthquakes and tremors) and other changes in gravity or electrical impulses.

Also, key in the study of undersea volcanoes is the subsequent earthquakes and tremors that occur after eruptions. Due to the fact that volcanic activities occur close to dry land or deep into the sea; they are bound to affect aquatic life and human life respectively. Their gas emissions also affect the environment. These variables will be categorically analyzed further in the study.

A group of Australian and French scientists have in the past undertaken several studies on the effects of deep sea volcanic eruptions on the environment and established that volcanic activities undersea produce large volumes of iron which plant species known as phytoplankton use to soak up carbon dioxide when they bloom (Fogarty, 2010).

Carbon dioxide being the main greenhouse gas in the world; the studies never focused on the impact of volcanic activity on the environment and especially carbon storage in the Ocean. Deep sea volcanoes are present under deep sea ridges of the ocean floor and the above research has been based on the amount of carbon dioxide that is present in depths of four kilometers on the ocean floor. The studies are therefore shallow.

Carbon is present in small volumes along the ocean floor and this prevents the growth of phytoplankton. However, science has often affirmed that large amounts of carbon often come from wind borne dust. This may be witnessed through sandstorms or iron rich sediments from the ocean which in turn triggers rampant phytoplankton growth (Fogarty, 2010).

At present, research studies have pointed out that deep sea volcanoes constantly produce a significant amount of iron over constant timescales. This has also been identified as the main factor which accounts for about 5%-10% of the total carbon storage in the oceans. Such studies have been observed in the Southern ocean but in other regions, the amount of carbon storage may go up to 30% (Fogarty, 2010).

The implication here is that the iron produced in the ocean and in turn the carbon retention witnessed, can act as a buffer when factors such as sandstorm vary. However, climate change has affected the progression of iron onto the earth’s surface, after deep sea volcanic eruptions. Ocean stratification has also been observed to be another cause of low iron penetration onto the earth’s surface (Fogarty, 2010).

Large amounts of Phytoplankton have been observed at the Antarctica, meaning the region is rich in iron. However, some studies have shown that huge winds will eventually blow the iron onto the ocean surface. In turn, more phytoplankton will grow and capture more carbon dioxide from the air (Fogarty, 2010). A vast network of deep sea volcanoes therefore produce mineral rich water each year soaking up large amounts of carbon dioxide produced by man. This has reduced the acceleration of global warming.

Deep sea volcanoes are known to cause massive landslides because of their massive cones (International Consortium on Landslides. General Assembly, 2005, p. 257). The main cause of landslides for deep sea volcanoes is caused by the very forces that created the volcanoes in the first place.

This is essentially the rise of lava. Every time lava is pushed aside, the surrounding rocks that create ground stability are shoved aside to make room for the molten rock. In turn, internal shear zones are created and this oversteps one or more sides of the cone (US Geological Surveys, 2009).

Normally, the magma that never comes out releases certain volcanic gases that are partially dissolved in the ocean, creating strong hydrothermal systems that further weaken the rock underneath the ocean floor and thereafter burning them to clay (US Geological Surveys, 2009). In addition, the thousands of layers of lava and rock debris often lead to fault lines that weaken the ocean surface. This is often accelerated by the downward pull of the cone by gravitational force.

These factors are especially detrimental when the deep sea volcano is near dry land. This easily triggers a landslide due to a weakened earth surface and also allows part of a volcanic cone to collapse under the pull of gravity into the volcano (US Geological Surveys, 2009).

Certain factors have been observed to accelerate this process including; intrusion of magma into the volcanic surface, deadly earthquakes under the ocean floor, and a saturation of the volcano with large volumes of water; especially preceding an earthquake (US Geological Surveys, 2009).

A Landslide caused by these volcanic activities often destroys everything that stands in its way and also initiates a flurry of activities like explosive eruptions, buried valleys, generation of lahars and a trigger of deadly waves that have even been witnessed in the recent past (like the tsunami) (US Geological Surveys, 2009).

In addition, such landslides may cause varying degrees of topographical effects; ranging from development of hills and closed depressions, created by accumulated debris. Sometimes, the deposits left by these volcanoes create tributaries and later cause flooding, either through the misdirection of tributaries or subsequent forming of lakes and other smaller water bodies (US Geological Surveys, 2009).

After eruptions, a large part of the volcano’s cone is usually displaced and this triggers the landslides which decrease the pressure on the magmatic and hydrothermal systems and in turn cause varying degrees of explosions, ranging from small to large steam explosions (US Geological Surveys, 2009).

Contrary to popular opinion that melting ice and rising temperatures are solely as a result of global warming, deep sea volcanic activities have been identified as another cause of this observation. In fact, scientists have reported that recent volcanic activity under the Arctic Ocean floor have resulted in a large spew of fragmented lava into the sea.

Such eruptions have been observed in Gukkel ridge which records one of the most massive eruptions that even buried Pompeii. This took place in 1999, from an underwater volcano located at the tip of green land near Siberia (Ajstrata, 2008).

Scientists have pondered whether there is a relation between subsequent earthquakes and volcanic explosions (School Specialty Publishing, 2006). Further explorations under the ocean rubbished reports that earthquakes were caused by slow spews of fragmented lava because they discovered that there were huge explosions taking place in the ocean (Ajstrata, 2008).

In understanding the melting of ice at the arctic, it should be understood that the Arctic Ocean resembles a closed system which has very limited outlets (Ajstrata, 2008). The natural basin and its characteristics emphasize the belief that volcanic eruptions are the cause of the melting ice because there isn’t much room for the heat generated out of the deep sea volcanic activities to circulate out of the basin. Ice and glaciers have therefore melted over the centuries.

These discoveries have led to many questions being asked about the real causes of ice melting. Interestingly, the arctic surface has recently had very thin surfaces of ice and either by sheer coincidence or not, the ocean floor underneath is home to some of the most active volcanoes on the ocean floor (Ajstrata, 2008). Evidence at the arctic therefore attests that volcanic activity is one of the primary reasons why ice is quickly melting on the global surface.

With regard to the thickness of ice underwater, it is often observed that bout 90% of icebergs is underwater. Interestingly, areas that have thick ice resemble inverted mountains but areas of thin ice resemble valleys (Ajstrata, 2008).

Evidently, if we were to analyze the effects of deep sea volcanoes, it makes perfect sense that the zone resembling a valley gets heated up fast because it takes less time for the heat to reach the ice and similarly, it would take a long time for the heat to reach the thick ice because of the stumbling inverted mountain-like barrier (Ajstrata, 2008).

There is enough evidence to prove that deep water volcanoes improve the aquatic life undersea. For instance, an active volcano at Guam has recently caught the attention of scientists because despite its regular spewing of lava, it remains home to numerous aquatic lives, including ocean critters, shrimps, limpets, crabs and barnacles (Rosaly, 2005, p. 20).

The volcano is now high enough to resemble a 12 storey building and with recent observations, there has been a growing population of aquatic animals living at the volcano’s dome. The development of a positive relationship between an increase in volcanic activity and the growing population of animals around the volcano is therefore inevitable.

Some scientists even point out that some of these animals found at the volcanic tip are completely new species. Interestingly, these animals are well adapted to their environment which is essentially toxic, in relation to other marine environments. Normal marine life wouldn’t survive there either (Ajstrata, 2008). It is therefore inevitable to conclude that the surrounding marine life is nourished by the deep sea volcanic activity.

Scientifically, this phenomenon has been explained by the slow deposits of bacterial filaments over surrounding rocks that provide a good source of food for the surrounding marine life (Ajstrata, 2008). Some shrimps have even been observed to have adapted to the volcanic environment by developing pruning claws to extract food from the rocks. Another animal species known as the Lohili shrimps has perfectly adapted to its environment by grazing on the bacterial filaments through the developments of garden like shears.

These species however graze as a primary source of obtaining food but as they develop into adult life, they develop their claws to become predators (Ajstrata, 2008). In this regard, the shrimps become predators and feed on dead animals like fish and squids which were jumped up by the volcano (Ajstrata, 2008). These underwater volcanoes have therefore provided better ground for understanding volcanic activities than volcanic mountains on land would.

Deep sea volcanoes have a huge impact on the environment. Virtually, marine life is largely dictated by volcanic activities that go on in deep waters. This is in reference to an evident change of aquatic life conditions especially in light of toxic gases released in the deep waters.

These volcanic activities also rival existing facts about global warming because their activities have been noted to increase world temperatures and result in ice and glaciers melting. In the same regard, landslides and earthquakes have been attributed to a destabilization of the earth’s surface by volcanic activities.

However, we cannot pass a blanket judgment that deep sea volcanoes only have detrimental effects because this study identifies that it helps reduce green gas emissions through carbon dioxide reduction. Conclusively this study identifies that the effects of deep sea volcanic activities have been largely underrated and more research needs to be done to quantify its effects.

Ajstrata. B. (2008). Global Warming or Simply Under Water Volcanoes . Web.

Fisher, R. (1998). Volcanoes: Crucibles of Change . New Jersey: Princeton University Press.

Fogarty, D. (2010). Deep-Sea Volcanoes Play Key Climate Role: Scientists . Web.

International Consortium on Landslides. General Assembly. (2005 ). Landslides: Risk Analysis and Sustainable Disaster Management: Proceedings of the First General Assembly of the International Consortium on Landslides. Amsterdam: Birkhäuser.

Patricia, L. (1999). The Oryx Guide to Natural History: The Earth and All Its Inhabitants . Boston: Greenwood Publishing Group.

Rosaly M. C. (2005). The Volcano Adventure Guide . Cambridge: Cambridge University Press.

School Specialty Publishing. (2006). World Atlas . New York: Carson-Dellosa Publishing.

US Geological Surveys, (2009). Volcano Landslides and their Effects . Web.

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Good Essay About Volcanic Eruption

Type of paper: Essay

Topic: Education , Disaster , Sea , Model , Rainfall , Volcano , Climate , Atmosphere

Words: 1000

Published: 05/31/2021

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There is a relationship between volcanic eruption and the climate of a place. After the eruption, the poisonous sulphur dioxide which is emitted out as a volcanic product, reacts and get oxidized to form sulphate aerosols in the stratosphere, hence affecting the climate adversely (Forster 2007). Volcanic ashes and particles having diameter larger than 2 um also affects the atmosphere. According to Ramaswamy (1996), ozone depletion results when the volcanic aerosols react with the balanced chemistry in the stratosphere. Mid and high latitudes volcanic eruptions create drastic climatic changes. The aerosols here retain over the hemisphere and cause climate to change. For example, the eruption of Laki volcano in Iceland in June was followed by ‘an exceptionally cold’ winter in 1783-84 (Thordason & Self 2003). The Millennium experiment has been used to study the climatic effects after volcanic eruptions in the mid and high latitudinal regions of the northern hemisphere with the coagulation of earth system model (Jungclaus et al, 2010). Jungclaus (2010) mentioned the use of COSMOS network which consisted of four models. The atmospheric general circulation model known as ECHAM5, the general circulation model known as MPI-OM, the ocean biogeochemistry model known as HAMMOC and lastly the land use and vegetation model JSBACH.

External natural forcing of the volcano, are based on observations, data and other references. The solar forcing depends on the tree ring and the ice core proxy reconstructions and also on the orbital forcing. Volcanic forcing is represented by varying the AOD at 0.55 um and the effective radius with a 10 days’ time resolution particularly for four latitudes: 30-90 degree north and south and 0-30 degree north and south latitudes. The volcanic AODs are based on a reconstruction. They used the data from 13 Greenland and Antarctic ice cores as the main source of data and spot data from the other sources. The effective radius growth and decay depends on the observations after the eruption happens. The temporal variation of the short wave radiation anomalies are based on changes in AOD, the solar zenith angle, the top surface of the atmosphere insolation and the surface albedo. Firstly, the aerosol radiative forcing becomes stronger with increasing AOD and secondly, the radiative forcing gets reduced in winter because the northern hemisphere receives less insolation than in summer. The AOD between 30 and 90 degree is horizontally uniform but in high latitudes, it is not uniform but peaks in summer. The temperature anomalies are similar to that of short wave radiation anomalies. The effects on the hemispheric scale are comparable with the internal variability of the model’s climate.

After evaluating the internal climate variability from a 1201 year simulation with the same model without external forcing, the result was that the standard deviation of northern hemisphere annual mean temperature was 0.24 K and the corresponding standard deviation for 2 years being 0.19 K. Anomalies are statistically significant at 90% level of large parts of continental and Arctic areas. Due to large heat capacity, the changes of the sea are small. After July, the largest anomalies start during autumn. The spatial distribution is similar to that in summer after January eruptions with anomalies smaller than 0.8 K. The distribution after the July eruption shows cooling over the Arctic sea. This is due to increased amount of sea ice during the autumn brought about by the cooling. September eruption caused the largest local anomalies in northeast Siberia, larger than 1.2 K and again above the continents and the Arctic Sea. In short, the volcanic eruptions in the Northern hemisphere in mid and high latitudes cause cooling over the continents and the northern ice sea as large as to 1 K. Internal and eruption induced climate variability sometimes causes slight warming in some regions.

The precipitation is also altered after a volcanic eruption. The precipitation anomalies tend to be negative after eruptions but a lot of variability exists. For example, after the January eruptions, the largest anomalies occur in September, December followed by next January and May. As earlier mentioned after an eruption, precipitation anomalies tend to be usually negative but only few of the mean monthly anomalies are statistically significant. A t-test was conducted considering the 21 months following the eruptions of January, July and September, the mean precipitation anomaly is 90% statistically significant. Hence, negative precipitation anomaly is significant. The result of the t-test shows larger variability in precipitation due to internal climate variability and other external factors.

The atmospheric carbon dioxide concentration anomalies are small after the eruptions around -0.0018 and 0.0043 kg per square meter compared to the mean burden of 4.3 kg per square meter. After the eruptions, anomalies are typically negative. In January and July eruptions, there are small positive anomalies during the summer and then larger positive anomalies in the following summer while for the September eruptions, no such increase is observed. The soil respiration and net primary production anomalies contributes to negative carbon dioxide burden while a slight reduction in the net primary production creates positive anomalies for January and July.

Summarising the paper, we have studied the change in climate in the mid and the high latitudes and also the anomalies associated with each climatic factor: temperature, precipitation, solar radiation, carbon dioxide burden etc and how the volcanic eruption affects these factors. The effects of eruption on temperature showed an average maximum temperature was -0.19 K and the average anomaly in the 21 months was -0.095 K following the eruptions. The average maximum anomaly in the hemisphere meant clear sky shortwave radiation was small. The effects of eruption on atmospheric carbon dioxide concentration were small. Precipitation anomalies also tend to be on a negative scale after the eruption.

Meronen, H. et al. ‘Climate Effects Of Northern Hemisphere Volcanic Eruptions In An Earth System Model’. Atmospheric Research 114-115 (2012): 107-118. Web.

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Essay on Volcanic Eruption | Geography

In this essay we will discuss about: 1. Introduction to Volcanic Eruption 2. Effects of Volcanic Eruption 3. Types.

Essay on Volcanic Eruption

1. essay on the introduction to volcanic eruption:.

Explosive eruptions can inject large quantities of dust and gaseous material (such as sulphur dioxide) into the upper atmosphere, where sulphur dioxide is rapidly converted into sulphuric acid aerosols. Whereas volcanic pollution of the lower atmosphere is removed within days by the effects of rainfall and gravity, stratospheric pollution may remain there for several years, gradually spreading to cover much of the globe.

The volcanic pollution results in a substantial reduction in the direct solar beam, largely through scattering by the highly reflective sulphuric acid aerosols. This can amount to tens of per cent. The reduction, is however, compensated for by an increase in diffuse radiation and by the absorption of outgoing terrestrial radiation (the greenhouse effect). Overall, there is a net reduction of 5 to 10% in energy received at the Earth’s surface.

Clearly, this volcanic pollution affects the energy balance of the atmosphere whilst the dust and aerosols remain in the stratosphere. Observational and modelling studies of the likely effect of recent volcanic eruptions suggest that an individual eruption may cause a global cooling of up to 0.3°C, with the effects lasting 1 to 2 years. Such a cooling event has been observed in the global temperature record in the aftermath of the eruption of Mount Pinatubo in June 1991.

The climate forcing associated with individual eruptions is, however, relatively short-lived compared to the time needed to influence the heat storage of the oceans. The temperature anomaly due to a single volcanic event is thus unlikely to persist or lead, through feedback effects, to significant long-term climatic changes.

Major eruptions have been relatively infrequent this century, so the long-term influence has been slight. The possibility that large eruptions might, during historical and pre-historical times, have occurred with greater frequency, generating long-term cooling, cannot, however, be dismissed. In order to investigate this possibility, long, complete and well-dated records of past volcanic activity are needed. One of the earliest and most comprehensive series is the Dust Veil Index (DVI) of Lamb (1970), which includes eruptions from 1500 to 1900.

When combined with series of acidity measurements in ice cores (due to the presence of sulphuric acid aerosols), they can provide valuable indicators of past eruptions. Using these indicators, a statistical association between volcanic activity and global temperatures during the past millennia has been found. Episodes of relatively high volcanic activity (1250 to 1500 and 1550 to 1700) occur within the period known as the Little Ice Age, whilst the Medieval Warm Period (1100 to 1250) can be linked with a period of lower activity.

Bryson (1989) has suggested a link between longer time scale volcanic variations and the climate fluctuations of the Holocene (last 10,000 years). However, whilst empirical information about temperature changes and volcanic eruptions remains limited, this, and other suggested associations discussed above , must again remain speculative.

Volcanic activity has the ability to affect global climate on still longer time scales. Over periods of millions or even tens of millions of years, increased volcanic activity can emit enormous volumes of greenhouse gases, with the potential of substantial global warming. However, the global cooling effects of sulphur dioxide emissions will act to counter the greenhouse warming, and the resultant climate changes remain uncertain. Much will depend upon the nature of volcanic activity. Basaltic outpourings release far less sulphur dioxide and ash, proportionally, than do the more explosive (silicic) eruptions.

2. Essay on the Effects of Volcanic Eruption:

There are many different types of volcanic eruptions and associated activity – phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.

The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapour is typically the most abundant volcanic gas, followed by carbon dioxide and sulphur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.

Large, explosive volcanic eruptions inject water vapour (H 2 O), carbon dioxide (CO 2 ), sulphur dioxide (SO 2 ), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16-32 kilometres (10-20 mi) above the Earth’s surface. The most significant impacts from these injections come from the conversion of sulphur dioxide to sulphuric acid (H 2 SO 4 ), which condenses rapidly in the stratosphere to form fine sulfate aerosols.

The aerosols increase the Earth’s albedo—its reflection of radiation from the Sun back into space – and thus cool the Earth’s lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth’s surface of up to half a degree (Fahrenheit scale) for periods of one to three years — sulphur dioxide from the eruption of Huaynaputina probably caused the Russian famine of 1601 – 1603.

One proposed volcanic winter happened c. 70,000 years ago following the super-eruption of Lake Toba on Sumatra Island in Indonesia. According to the Toba catastrophe theory to which some anthropologists and archeologists subscribe, it had global consequences, killing most humans then alive and creating a population bottleneck that affected the genetic inheritance of all humans today.

The 1815 eruption of Mount Tambora created global climate anomalies that became known as the “Year without a summer” because of the effect on North American and European weather. Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in one of the worst famines of the 19th century. The freezing winter of 1740-41, which led to widespread famine in northern Europe, may also owe its origins to a volcanic eruption.

It has been suggested that volcanic activity caused or contributed to the End-Ordovician, Permian-Triassic, Late Devonian mass extinctions, and possibly others. The massive eruptive event which formed the Siberian Traps, one of the largest known volcanic events of the last 500 million years of Earth’s geological history, continued for a million years and is considered to be the likely cause of the “Great Dying” about 250 million years ago, which is estimated to have killed 90% of species existing at the time.

The sulfate aerosols also promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (CIO), which destroys ozone (O 3 ). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth’s radiation balance.

Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.

Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year. Volcanic eruptions may inject aerosols into the Earth’s atmosphere. Large injections may cause visual effects such as unusually colourful sunsets and affect global climate mainly by cooling it.

Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.

Ash thrown into the air by eruptions can present a hazard to aircraft, especially jet aircraft where the particles can be melted by the high operating temperature. Dangerous encounters in 1982 after the eruption of Galunggung in Indonesia, and 1989 after the eruption of Mount Redoubt in Alaska raised awareness of this phenomenon. Nine Volcanic Ash Advisory Centers were established by the International Civil Aviation Organization to monitor ash clouds and advise pilots accordingly. The 2010 eruption of Eyjafjallajokull caused major disruptions to air travel in Europe.

3. Essay on the Types of Volcanic Eruption:

During a volcanic eruption, lava, tephra (ash, lapilli, solid chunks of rock), and various gases, are expelled from a volcanic vent or fissure.

Several types of volcanic eruptions have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behaviour has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types.

1. Magmatic Eruptions:

Magmatic eruptions produce juvenile clasts during explosive decompression from gas release. They range in size from the relatively small fire fountains on Hawaii to > 30 km Ultra Plinian eruption columns, bigger than the eruption that buried Pompeii.

2. Strombolian Eruptions:

Strombolian eruptions are relatively low-level volcanic eruptions, named after the Italian volcano Stromboli, where such eruptions consist of ejection of incandescent cinder, lapilli and lava bombs to altitudes of tens to hundreds of meters. They are small to medium in volume, with sporadic violence.

They are defined as “…Mildly explosive at discrete but fairly regular intervals of seconds to minutes…”

The tephra typically glows red when leaving the vent, but its surface cools and assumes a dark to black colour and may significantly solidify before impact. The tephra accumulates in the vicinity of the vent, forming a cinder cone. Cinder is the most common product, the amount of volcanic ash is typically rather minor. The lava flows are more viscous and therefore shorter and thicker, than the corresponding Hawaiian eruptions; it may or may not be accompanied by production of pyroclastic rock.

Instead the gas coalesces into bubbles, called slugs, that grow large enough to rise through the magma column, bursting near the top due to the decrease in pressure and throwing magma into the air. Each episode thus releases volcanic gases, sometimes as frequently as a few minutes apart. Gas slugs can form as deep as 3 kilometers, making them difficult to predict.

Strombolian eruptive activity can be very long-lasting because the conduit system is not strongly affected by the eruptive activity, so that the eruptive system can repeatedly reset itself. For example, the Paricutin volcano erupted continuously between 1943-1952, Mount Erebus, Antarctica has produced Strombolian eruptions for at least many decades, and Stromboli itself has been producing Strombolian eruptions for several thousand years.

3. Vulcanian Eruption:

Vulcanian eruptions are a type of volcanic eruption characterised by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak. They usually commence with phreatomagmatic eruptions which can be extremely noisy due the rising magma heating water in the ground. This is usually followed by the explosive clearing of the vent and the eruption column is dirty grey to black as old weathered rocks are blasted out of the vent. As the vent clears, further ash clouds become grey-white and creamy in colour, with convolution of the ash similar to those of plinian eruptions.

The tephra is dispersed over a wider area than that from Strombolian eruptions. The pyroclastic rock and the base surge deposits form an ash volcanic cone, while the ash covers a large surrounding area. The eruption ends with a flow of viscous lava. Vulcanian eruptions may throw large metre-size blocks several hundred metres, occasionally up to several kilometres.

The term Vulcanian was first used by Giuseppe Mercalli, witnessing the 1888-1890 eruptions on the island of Vulcano. His description of the eruption style is now used all over the world. Mercalli described vulcanian eruptions as “…Explosions like cannon fire at irregular intervals…”

Their explosive nature is due to increased silica content of the magma. Almost all types of magma can be involved, but magma with about 55% or more silica (basalt-andesite) is most common. Increasing silica levels increase the viscosity of the magma which means increased explosiveness.

Vulcanian eruptions are dangerous to persons within several hundred metres of the vent. One feature of this type of eruption is the “Volcanic bomb.” These can be blocks often 2 to 3 m in dimensions. At Galeras a vulcanian eruption ejected bombs which impacted with several volcanologists who were in the crater and many died or suffered terrible.

4. Pel é an Eruption:

Peléan eruptions are a type of volcanic eruption. They can occur when viscous magma, typically of rhyolitic or andesitic type, is involved, and share some similarities with Vulcanian eruptions. The most important characteristics of a Peléan eruption are the presence of a glowing avalanche of hot volcanic ash, a pyroclastic flow. Formation of lava domes is another characteristical feature. Short flows of ash or creation of pumice cones may be observed as well.

The initial phases of eruption are characterised by pyroclastic flows. The tephra deposits have lower volume and range than the corresponding Plinian and Vulcanian eruptions. The viscous magma then forms a steep-sided dome or volcanic spine in the volcano’s vent.

The dome may later collapse, resulting in flows of ash and hot blocks. The eruption cycle is usually completed in few years, but in some cases may continue for decades, like in the case of Santiaguito. The 1902 explosion of Mount Pelée is the first described case of a Peléan eruption, and gave it its name.

Some other examples include the following:

i. The 1948-1951 eruption of Hibok-Hibok;

ii. The 1951 eruption of Mount Lamington, which remains the most detailed observation of this kind;

iii. The 1956 eruption of Bezymianny;

iv. The 1968 eruption of Mayon Volcano;

v. And the 1980 eruption of Mount St. Helens.

5. Hawaiian Eruption:

A Hawaiian eruption is a type of volcanic eruption where lava flows from the vent in a relative gentle, low level eruption, so called because it is characteristic of Hawaiian volcanoes. Typically they are effusive eruptions, with basaltic magmas of low viscosity, low content of gases, and high temperature at the vent. Very little amount of volcanic ash is produced. This type of eruption occurs most often on hotspot volcanoes such as Kilauea, though it can occur near subduction zones (e.g. Medicine Lake Volcano in California, United States.) Another example of Hawaiian eruptions occurred on Surtsey from 1964 to 1967, when molten lava flowed from the crater to the sea.

Hawaiian eruptions may occur along fissure vents, such as during the eruption of Mauna Loa Volcano in 1950, or at a central vent, such as during the 1959 eruption in Kilauea Iki Crater, which created a lava fountain 580 meters (1,900 ft) high and formed a 38 meter cone named Pu’u Pua’i. In fissure-type eruptions, lava spurts from a fissure on the volcano’s rift zone and feeds lava streams that flow downslope. In central-vent eruptions, a fountain of lava can spurt to a height of 300 meters or more (heights of 1600 meters were reported for the 1986 eruption of Mount Mihara on Izu Ôshima, Japan).

Hawaiian eruptions usually start by formation of a crack in the ground from which a curtain of incandescent magma or several closely spaced magma fountains appear. The lava can overflow the fissure and form pahoehoe style of flows. Eruptions from a central cone can form small lightly sloped shield volcanoes, for example the Mauna Loa.

6. Surtseyan Eruption:

A Surtseyan eruption is a type of volcanic eruption that takes place in shallow seas or lakes. It is named after the island of Surtsey off the southern coast of Iceland.

These eruptions are commonly phreatomagmatic eruptions, representing violent explosions caused by rising basaltic or andesitic magma coming into contact with abundant, shallow groundwater or surface water. Tuff rings, pyroclastic cones of primarily ash, are built by explosive disruption of rapidly cooled magma. Other examples of these volcanoes-Capelinhos, Faial Island, Azores; and Taal Volcano, Batangas, Philippines.

Several Specific Characteristics:

i. Physical nature of magma – viscous; basaltic.

ii. Character of explosive activity – violent ejection of solid, warm fragments of new magma; continuous or rhythmic explosions; base surges.

iii. Nature of effusive activity – short, locally pillowed, lava flows; lavas may be rare.

iv. Nature of dominant ejecta – lithic, blocks and ash; often accretionary lapilli; spatter, fusiform bombs and lapilli absent.

v. Structures built around vent – tuff rings

7. Plinian Eruption:

Plinian eruptions, also known as ‘Vesuvian eruptions’, are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in AD 79, which killed Pliny the Elder.

Plinian eruptions are marked by columns of gas and volcanic ash extending high into the stratosphere, a high layer of the atmosphere. The key characteristics are ejection of large amount of pumice and very powerful continuous gas blast eruptions. Key characteristics are ejection of large amount of pumice and very powerful continuous gas blast eruptions.

Short eruptions can end in less than a day, but longer events can take several days to months. The longer eruptions begin with production of clouds of volcanic ash, sometimes with pyroclastic flows. The amount of magma erupted can be so large that the top of the volcano may collapse, resulting in a caldera. Fine ash can deposit over large areas. Plinian eruptions are often accompanied by loud noises, such as those generated by Krakatoa.

The lava is usually rhyolitic and rich in silicates. Basaltic lavas are unusual for Plinian eruptions; the most recent example is the 1886 eruption of Mount Tarawera.

8. Phreatomagmatic Eruptions :

Phreatomagmatic eruptions are the result of thermal contraction from chilling on contact with water. The products of phreatomagmatic eruptions are believed to have more regular shard shapes and be finer grained than the products of magmatic eruptions because of the different eruptive mechanism.

There is debate about the exact nature of the eruptive style. Fuel-coolant reactions may be more critical to the explosive nature than thermal contraction. Fuel coolant reactions fragment the material in contact with a coolant by propagating stress waves widening cracks and increasing surface area leading to rapid cooling rates and explosive thermal contraction.

9. Submarine Eruption:

A submarine eruption is a type of volcanic eruption where lava erupts under an ocean. Most of the Earth’s volcanic eruptions are submarine eruptions, but few have been documented because of the difficulty in monitoring submarine volcanoes. Most submarine eruptions occur at mid-ocean ridges and near hotspots.

10. Sub-Glacial Eruption:

A sub-glacial eruption is a volcanic eruption that has occurred under ice, or under a glacier. Sub-glacial eruptions can cause dangerous floods, lahars and create hyaloclastite and pillow lava. Only five of these types of eruptions have been recorded in recent history. Sub-glacial eruptions sometimes form a sub-glacial volcano called a tuya. Tuyas in Iceland are called Table Mountains because of their flat tops. Tuya Butte, in northern British Columbia is an example of a tuya.

A tuya may be recognized by its stratigraphy, which typically consists of a basal layer of pillow basalts overlain by hyaloclastite breccia, tuff, and capped off by a lava flow. The pillow lavas formed first as a result of subaqueous eruptions in glacial melt-water. Once the vent reaches shallower water, eruptions become phreatomagmatic, depositing the hyaloclastite breccia. Once the volcano emerges through the ice, it erupt lava, forming the flat capping layer of a tuya.

The thermodynamics of sub-glacial eruptions are very poorly understood. Rare published studies indicate that plenty of heat is contained in the erupted lava, with 1 unit-volume of magma sufficient to melt about 10 units of ice. However, the rapidity by which ice is melted is unexplained, and in real eruptions the rate is at least an order of magnitude faster than existing predictions.

Antarctica eruption-On January, 2008, the British Antarctic Survey that scientists led by Hugh Corr and David Vaughan, reported (in the journal Nature Geoscience) that 2,200 years ago, a volcano erupted under Antarctica ice sheet (based on airborne survey with radar images).

The biggest eruption in the last 10,000 years, the volcanic ash was found deposited on the ice surface under the Hudson Mountains, close to Pine Island Glacier. The ash covered an area the size of New Hampshire and was probably deposited from a 12 km high ash plume. Researchers have detected a mountainous peak some 100 meters beneath the surface believed to be the top of the tuya associated with this eruption.

11. Phreatic Eruption :

A phreatic eruption, also called a phreatic explosion or ultra-vulcanian eruption occurs when rising magma makes contact with ground or surface water. The extreme temperature of the magma [anywhere from 600 to 1,170°C (1,112 to 2,138°F)] causes near-instantaneous evaporation to steam resulting in an explosion of steam, water, ash, rock, and volcanic bombs. At Mount St. Helens hundreds of steam explosions preceded a 1980 plinian eruption of the volcano. A less intense geothermal event may result in a mud volcano. In 1949, Thomas Jaggar described this type of activity as a steam-blast eruption.

Phreatic eruptions typically include steam and rock fragments; the inclusion of lava is unusual. The temperature of the fragments can range from cold to incandescent. If molten material is included, the term phreatomagmatic may be used. These eruptions occasionally create broad, low-relief craters called maars. Phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas emissions. The former can asphyxiate at sufficient concentration; the latter is a broad spectrum poison. A 1979 phreatic eruption on the island of Java killed 149 people, most of whom were overcome by poisonous gases.

It is believed the 1883 eruption of Krakatoa, which obliterated most of the volcanic island and created the loudest sound in recorded history, was a phreatic event. Kilauea, in Hawaii, has a long record of phreatic explosions; a 1924 phreatic eruption hurled rocks estimated at eight tons up to a distance of one kilometer. Additional examples are the 1963-65 eruption of Surtsey, the 1965 eruption of Taal Volcano, and the 1982 Mount Tarumae eruption.

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Empty Roads and Spewing Lava: 4 Months Into Iceland’s Eruptions

Volcanic eruptions are continuing in the Reykjanes Peninsula in Iceland. Streets are empty and the Blue Lagoon resort remains closed.

The plume from a volcanic eruption as viewed from Route 41 near the town of Kalfatjorn in western Iceland on Wednesday. Credit...

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By Claire Moses

Photographs by Tony Cenicola

• March 29, 2024

The scene is as spectacular as it is dangerous: flowing rivers of shimmering lava and a dramatic plume of toxic gas.

That image has been the reality for much of the past four months in the Reykjanes Peninsula in southern Iceland, which the country’s tourism website has called a “geological wonder where lighthouses outnumber villages.”

A series of volcano eruptions began in December after hundreds of earthquakes shook the peninsula, cracking open a fissure that sent lava spewing into a residential neighborhood for the first time in more than four decades. The volcanic system has erupted several more times since then.

Grindavik, a fishing town of more than 3,500 people about 30 miles southwest of the country’s capital, Reykjavik, has been evacuated, and the nearby Blue Lagoon, a popular geothermal spa, has been largely closed since early November.

While much of life goes on in the rest of Iceland, the eruptions have had an effect beyond the peninsula, disrupting the tourism operations of a country that relies heavily on visitors .

Icelandair said it has seen a negative impact on bookings because of the threat of the eruptions. While the overall number of passengers carried by the airline in February increased compared to last year, the number flying to Iceland dropped by 8 percent, according to the airline.

While the eruptions continue, the situation has been “steady” this week, according to the Icelandic Meteorological Office, the country’s weather service. But lava continues to flow from three craters toward Grindavik, the service said.

The eruptions also produce high levels of gas pollution. The concentration of sulfur dioxide in the air is “very unhealthy,” according to the Met Office, which added that “people are likely to experience respiratory symptoms if exposed.”

The Blue Lagoon, a spa and hotel complex in Grindavik, is closed at the moment. It first temporarily shut its doors in November after thousands of earthquakes, signs of the impending eruption, hit the region.

The resort has reopened occasionally, but has been closed for more than 85 days since then, the hotel said in an email. It is currently on its sixth closure since Nov. 9.

Lava damaged several houses in Grindavik when it breached a defense wall that was supposed to route it away from the town.

Around the town, earthquakes caused cracks in the streets. Breaks in the roads have been filled with gravel.

The authorities continue to warn visitors to stay away from the eruption site. “The edges of the new lava field are unstable and large chunks of lava can fall suddenly,” the Met Office said,

Claire Moses is a reporter for the Express desk in London. More about Claire Moses

Tony Cenicola is a Times photographer. More about Tony Cenicola

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Iceland volcano eruption: Piercing alarm rang loud as orange glow of a mushroom cloud filled the sky

Iceland is witnessing its fourth volcanic eruption in less than three months, as spectacular lava flows light up the night sky.

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Monday 18 March 2024 12:37, UK

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The alarm came loud and long - piercing and insistent. And when I opened our hotel bedroom door seconds later, there were already hotel workers running down the corridor.

A window immediately opposite our room held the answer for the urgent reaction. It was filled with a huge orange glow of a mushroom cloud billowing into the skies.

If there'd been any doubt, it was dispelled in that moment. The volcano on the Reykjanes Peninsula had erupted again - and with force .

It looked like it was on the doorstep of our hotel. In fact, it was a few kilometres away, but my family and I were among the five to six hundred people in the area at the time.

An emergency evacuation plan immediately swung into operation to get us all out - and quickly.

Our family of six happened to be in Iceland for a five-day break to celebrate two significant family birthdays. They were originally planned and then postponed a week before the coronavirus pandemic forced a worldwide lockdown.

We'd only just re-arranged and had only been in Iceland for two nights when what's looking like one of the most powerful recent eruptions occurred.

More on Iceland

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The Blue Lagoon area is one of Iceland's most popular tourist attractions and the hotels here were almost full. The authorities say they'd warned for weeks of an imminent eruption.

Iceland's Civil Protection Agency said before the eruption: "Since 24 October, scientists at the Icelandic Met Office have been monitoring a rise in seismic activity on the Reykjanes Peninsula which may signal an impending volcanic eruption.

"The heightened intensity of these seismic events particularly near the town of Grindavik indicates the potential for volcanic activity in the area."

Read more from Sky News: World's largest election to start next month Kim Jong Un rides in limousine gifted to him by Putin

If those warnings spelled imminent danger and the intensity of the eruption which happened on Saturday night, the hotel staff and the locals we'd spent the day with knew little about it. There was no indication at all that anything dramatic was about to happen.

The entrance to the Blue Lagoon area was still pitted with roadwork signs and warning notices cordoning off lava which was still smoking from the earlier eruptions.

We drove past the smoking rock formations just minutes before the latest eruption with our guide telling us about the fresh safety measures which had been enacted since last month.

Iceland had already seen three volcanic eruptions since December. But the fourth on Saturday night is thought to be the most powerful of recent times and is believed to be around the same location as February's eruption.

That saw red-hot lava flow down dangerously close to the Blue Lagoon area and across the entrance roads. Since February, the authorities had carved a new road and built protective dykes around the lagoon which is famed for his restorative mineral properties.

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All the guests had been given plans for possible evacuation before arriving. But I was speaking to hotel workers just a few minutes before the eruption about plans for the following day and no one in the hotel appeared to be aware of the seismic activity which very shortly ensued.

Text messages appeared on our mobile phones as the alarms went off, first in Icelandic then in English. "Evacuate, Evacuate. Leave the area immediately," it read. "Call 112 if you need help EVACUATE EVACUATE."

The car park was crowded with vehicles indicating a lot of visitors inside the lagoon area. Many of them were in the water when the eruption happened and were seen running through the hotel and back to their rooms in swimming costumes and dressing gowns to gather up their belongings.

In less than half an hour, all tourists had been rounded up and boarded on to a fleet of buses. Our family was the last to leave.

A few dozen residents of the nearby fishing village of Grindavik had only just returned to their homes. The town has been virtually a ghost area since being evacuated in November. They too received text messages urging them to leave the area.

Iceland is used to volcanic eruptions with more than thirty active volcanoes, making it the most active in Europe and attracting thousands of volcano tourists each year.

The most disruptive recently was in 2010 when the eruption of Eyjafjallajokull led to the widespread closure of airspace across Europe.

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Iceland's latest volcanic eruption is decreasing in power, and defenses are holding

L ava from a volcanic eruption in Iceland flowed Sunday toward defenses around the town of Grindavik, which have so far held the molten rock back from the evacuated community.

Scientists said the eruption appeared to be weakening and would probably taper off within hours.

A volcanic system on the Reykjanes Peninsula in the country's southwest erupted late Saturday for the fourth time in three months , sending orange jets of lava into the night sky.

Iceland’s Meteorological Office said the eruption opened a fissure in the earth almost 2 miles long between the mountains of Stóra-Skógfell and Hagafell.

The Met Office said Sunday that lava was flowing south and southeast at about 0.6 miles an hour, and might reach the ocean. Defensive barriers were built to stop it from inundating the main road along the peninsula’s southern coast.

Hundreds of people were evacuated from the Blue Lagoon thermal spa, one of Iceland’s top tourist attractions, when the eruption began, national broadcaster RUV said.

No flight disruptions were reported at nearby Keflavik, Iceland’s main airport.

The eruption site is a few miles northeast of Grindavik, a coastal town of 3,800 people about 30 miles southwest of Iceland’s capital, Reykjavik.

The town was evacuated before the initial eruption on Dec. 18. A second eruption that began on Jan. 14 sent lava toward the town. Defensive walls that had been bolstered after the first eruption stopped some of the flow, but several buildings were consumed by the lava.

Both eruptions lasted only a matter of days. A third eruption began Feb. 8. It ended within hours, but not before a river of lava engulfed a pipeline, cutting off heat and hot water to thousands of people.

Iceland, which sits above a volcanic hot spot in the North Atlantic, sees regular eruptions and is highly experienced at dealing with them. The most disruptive in recent times was the 2010 eruption of the Eyjafjallajokull volcano , which spewed huge clouds of ash into the atmosphere and led to widespread airspace closures over Europe.

The latest eruptions signal a reawakening of the Svartsengi volcanic system after almost 800 years of quiet. It's unclear when the activity will end or what it means for the Reykjanes Peninsula, one of the most densely populated parts of Iceland.

No confirmed deaths have been reported from any of the recent eruptions, but a workman was declared missing after falling into a fissure opened by the volcano.

Di Marco writes for the Associated Press.

This story originally appeared in Los Angeles Times .

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Vanuatu volcano alert bulletin n°5 - ambrym activity (march 28th 2024).

• Govt. Vanuatu

Attachments

AMBRYM VOLCANO 16°15’00”S 168°07’00”E Summit Elevation 4377ft (1334m) Current Vanuatu Volcano Alert Level: Level 2

Ambrym volcanic activity is continuing in the major unrest state. The Ambrym Volcanic Alert Level remains at Level 2.

Major unrest volcanic activity is continuing at Benbow and Marum volcanic craters. New field observations and seismic data analysis confirmed that the Ambrym volcanic activity conditions is unstable at the major unrest level. Ambrym volcano activity is likely to continue at similar level, consistent with Volcanic Alert Level 2. The danger zone for life safety is limited at 1 km radius from Marum crater and 2 km radius from Marum crater and major cracked of 2018 eruption at the south eastern part of Ambrym.

Latest observation photos from the field confirmed that its volcanic activity is confined inside the Benbow and Marum which consist of small steam cloud (fumarole). Volcanic hazards remain inside Benbow crater, areas around Marum crater and areas of major cracks of 2018 eruption at the South East of Ambrym.

The Ambrym volcanic Alert Level has been at Level 2 since 17th January 2024. Observations of the current activity are consistent with the Volcanic Alert Level 2. Level 2 indicates “Major unrest. The danger zone is at the Exclusion Zone which is about 1 km radius from Benbow crater and the Danger Zone A which is about 2 km radius from Marum crater with major cracked areas at the south eastern part of Ambrym” . With this current volcanic activity, it is a useful reminder that eruptions can occur with little or no warnings.

Ambrym volcano is a very active volcano in Vanuatu with large caldera of 12 km in diameter and 2 active craters Marum and Benbow. The volcano has been active during historical time at both summit and flank vents, producing moderate explosive eruptions and lava flows that have reached the coast. The larger events include eruptions in 1820, 1894, 1913 or 1929. Over the last seventy years, there are no extracaldera eruptions. The eruption of 1988 and 2015 are focused in the caldera.

All tourism agencies, local autorithies, people of Ambrym and the general public are reminded NOT to access the Permanent Exclusion Zone which is about 1 km radius inside Benbow crater and the Danger Zone A which is about 2 km radius around Marum crater (including Maben-Mbwelesu, Niri-Mbwelesu and Mbwelesu) ( See Ambrym caldera safety map below ). In thèse areas volcanic gases are expected and 2018 eruption major cracks can collapse in areas around Benbow and Marum craters anytime. Moreover, communities from South East Ambrym are advised not to access 2018 eruption major cracks at the South East of Ambrym . Ambrym volcano advice key message and information about volcanic hazards can be found at the link below:

https://www.vmgd.gov.vu/vmgd/index.php/geohazards/volcano/volcano-info/resources .

The Vanuatu Meteorology and Geohazards Department continues to closely monitor this volcano activity. More information will be provided as soon as necessary.

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