Indias Active Volcano RSTV In Depth

Rajya Sabha TV programs like ‘The Big Picture’, ‘In Depth’ and ‘India’s World’ are informative programs that are important for UPSC preparation. In this article, you can read about the discussions held in the ‘In Depth’ episode on India’s Active Volcano for the IAS exam.

Anchor: Teena Jha

Importance of this Episode:

• India’s live volcano in the Andaman and Nicobar islands is erupting once again. Video footage shows lava and ash is being thrown up on the north flank of the Barren Island. The eruption could be linked to the recent earthquake that rocked Indonesia in Southeast Asia.
• Barren Island- as the name suggests- is an uninhabited island, located about 140 kilometers from Port Blair.
• This edition of In Depth will look at the reasons for the current eruption of South Asia’s lone active volcano.
• It will also bring you the world’s biggest volcanoes and the disruptions they cause worldwide.

Historical Background

• • The Barren Island volcano stands on the seismically active Indian and Burmese plates.
  • Estimated to be 1.8 million years old, the volcano has been dormant since 1803, with an unconfirmed eruption in 1852. It was active once again in 1991, when the eruptions went on for over 6 months. Since then, it has shown intermittent activity. The latest was earlier this month, i.e. October, 2018.
  • Located in the Andaman and Nicobar Islands, it is the only active Indian Volcano.
  • It has started to spew lava and ash. Geologists say that the eruption can be linked to the recent earthquake that rocked Indonesia. The Geological Survey of India recorded its first eruption on 25th September, 2018.
  • Satellite images show fresh lava flow towards the North-West from the active cone of the volcano. In the days preceding the eruption, the Indian National Center for Ocean Information Services, Hyderabad, recorded earthquakes between 4.3 and 4.9 magnitudes on the richter scale in the Indonesian region.
  • On 28th September, 2018, an earthquake of 7.5 magnitude hit near Sulawesi near Indonesia, killing more than 1500 people.
  • When we look at the map of the Andaman and Nicobar Islands, they have a shape that resembles an arc, and if we look at this arc shape, it merges with the Indonesian Islands. The Andaman and Nicobar Islands, along with the Indonesian Islands form an “Island Arc”.

• This “Island Arc” is created by two lithospheric plates that are colliding. Both are oceanic plates, and one plate goes below the other plate. And once the material passes through depths where heat is so that the rocks get melted, those melted material ooze out in the form of volcanoes.

A Few Facts on Barren Island:

• • It is located 135 Kms north-east of Port Blair.
  • It is the only active volcano in South Asia.
  • The three kilometre wide island has a 2 kilometre wide depression, which have resulted from massive eruptions in the past.
  • The first massive eruption of the volcano took place in 1787.
  • In 1991, it erupted again after remaining dormant for about 150 years.  
  • Since then, it has shown intermittent activity, including eruptions in 1995 and 2005.
  • The eruption in 2005 occurred almost a year after the 2004 Tsunami that was triggered by an earthquake in Indonesia.
  • The last recorded volcanic eruption on Barren Island was in February, 2016.
  • Ash clouds and red lava spewing was also observed in early 2017.
  • However, according to a study conducted by ISRO scientists, the volcanic spewing that occurred in 2017 was a continuation of the eruption that took place in 2005.
  • The scientists used satellite data to understand the changes in the volcanic region, in terms of shape, area and path of lava flows between 2005 and 2017.
  • We can call Barren Island an active volcano, however, there is no danger here. Because it is located in a far-off place. Also, active volcanoes don’t pose danger- this is because we know that they are active. Their activities are measured, the geothermal energy which they emit is monitored, and thus, they do not pose any danger. But, those volcanoes that have been dormant for a large part in their life and in recent times, they haven’t erupted, give less time to people in the event of an eruption.
  • Scientists have found that the eruption in 2005, have created passages of lava flow in three different directions. Earlier, lava was flowing only in the west. The study also confirmed that the lava extrusion has also increased post the 2005 eruption.
  • Barren Island is a subaerial volcano as it comes out of the ocean, but we also have some submarine volcanoes. They are also present in the Andaman region. This is the same chain that goes towards the Sumatra subduction zone.

• There is another volcano known as Narcondam Volcano. But this volcano is considered to be a dormant volcano. It has not erupted in the last few thousand years.

• The Barren Island which is 354 metres high, is the emergent summit of a volcano that rises from a depth of 2250 metres. The entire zone is tectonically quite active. The incidence of a volcanic eruption is quite difficult to predict, but the constant monitoring of eruptions, help in understanding their causes and outcomes and devising mitigation strategies.

What is a Volcano?

A Volcano is an opening in the earth’s crust that allows molten rock, gases and debris to escape to the surface. The molten rock is called magma when it is beneath the surface and lava when it erupts or flows from a volcano. Along with lava, volcanos also release gases, ash and rock. In fact, it is a superhot mix that can be both incredibly destructive and creative. A volcanic eruption may involve lava and other debris that can flow up to 100 miles per hour, destroying everything that comes in their path.

Forms of Volcanoes:

• Volcanoes can be active, dormant or extinct.
• Active volcanoes are those that have had recent eruptions or are expected to have eruptions in the near future. Dormant volcanoes no longer produce eruptions, but might do so in the future.
• Extinct volcanoes are likely to never erupt again.

On earth, the erupted material can be liquid, rock, or lava when it’s on the surface, and magma when it is underground. It can also be ash, cinders, and gas. There are three reasons why magma erupts onto earth’s surface:

1. Magma rises when earth’s tectonic plates slowly move away from each other. Magma rises up to fill this space, even if it is underwater.
2. Magma also rises when tectonic plates move towards each other. When this happens, a part of earth’s crust is forced deep into its interior. The high heat and pressure causes the crust to melt and rise as magma. Magma rises through hot spots inside the earth. Hot spots are hot areas inside the earth which heat up magma, makes it less dense and makes it rise.

Fortunately, in Barren Island, there is no population around it. However, when the volcano does erupt, a lot of dust and smoke goes up which disrupts the flight paths. Thus, flights get diverted.

Types of Volcanoes:

Volcanoes fall into 4 types.  

1. Cinder Cone:

• They are the simplest form of volcano. They erupt when magma is ejected from a volcanic vent.
• The Ejected lava rains down, forming an oval-shaped cone with a bowl-shaped crater on top. These volcanoes are typically small, with few ever growing larger than about 300 metres above their surroundings.

1. Composite Volcanoes:

• These volcanoes are also called stratovolcanoes. These are formed when a volcano conduit connects a subsurface magma reservoir to the earth’s surface.
• These volcanoes have several vents that cause magma to break through walls and spew from fissures on the sides of the mountain as well as the summit.
• These volcanoes have violent eruptions. Shield volcanoes are large, and broad-surfaced where the lava is thin, allowing it to travel great distances down the shallow slopes.
• This lava cools and builds up slowly over time, with hundreds of eruptions creating many layers. These volcanoes are not likely to be catastrophic.

• Shield Volcano:

• A shield volcano is a wide volcano with shallowly-sloping sides.
• Shield volcanoes are formed by lava flows of low viscosity- lava that flows easily.

• Lava Domes:

• Lava domes are created by small masses of lava that are too vicious to flow far.
• The Dome grows over time and the mountain forms from material. Lava domes explode violently, releasing hot rock and ash.

• Submarine Volcanoes:

• Volcanoes can also be found on the ocean floor.  These are known as submarine volcanoes. These are often revealed through the presence of blasting steam and rocky debris over the ocean’s surface, though the pressure of the ocean’s water can often prevent an explosive release.
• The lava cools quickly on contact with the ocean water and forms pillow-shaped masses on the ocean floor. Over time, the formations can become so large that they may become islands.

• Subglacial Volcanoes:

• Volcanoes can also develop under ice-caps. These are known as subglacial volcanoes. Here flat lava flows on top of pillow lava,  which results from lava quickly cooling upon contact with ice. When the icecap melts, the lava on top collapses, leaving a flat-topped mountain.
• It is important to note that volcanoes bring lots of minerals when they erupt. The soil becomes more fertile.
• The soil in these island belts are very fertile, because it is rich in minerals. Volcanoes also create new land. The Hawaiian islands were created by eruptions of shield volcanoes.
• Ash from volcanoes adds minerals to the soil. This helps plants to grow stronger.
• Volcanoes also remove heat from earth’s interior and keeps our planet cool. In recent years, scientists have turned to volcanoes to help power cities. Researchers are exploring geothermal energy by tapping into volcanic heat to generate electricity. In Iceland, 25% of the energy generated is geothermal.
• History is witness to some massive volcanic eruptions. About 40 eruptions of the highest magnitude within the last 132 million years have been identified if which 30 have occurred in the past 36 million years.
• The power of volcanic eruptions are measured using the “Volcanic Explosivity Index”.
  It was devised by Chris Newhall of the United States Geological Survey and Stephen Self at the University of Hawaii in 1982.
• The scale is open-ended with the largest volcanoes in history given the magnitude of 8, each succeeding VEI is ten times greater than the last. There have not been any VEI 8 volcanoes in the last 10,000 years. But human history has seen some powerful and devastating eruptions of VEI 7 in the same time period.

Some Major Explosions:

• Mount Tambora:

• The 1815 eruption of Mount Tambora was the biggest in human history, with a VEI of 7. It occurred on the Indonesian island of Sumbawa. There was between 6 months and 3 years of steaming and small eruptions after the initial one, leaving at least 1,00,000/- people dead.
• Because of the 400 million tonne cloud of gas that the volcano created, the earth began to cool and the year, 1816 became known as the “Year Without Summer” because of the low temperatures which killed crops and led to mass starvation.

• Krakatoa:

• The volcanic island of Krakatoa which is between the Indonesian islands of Java and Sumatra erupted in 1883 with a force 13,000 times that of the atomic bomb that was dropped on Hiroshima in 1945.
• The sound of the explosion was heard over 3,000 miles away from its point of origin. The eruption produced a 130 foot high Tsunami which destroyed villages and killed over 36,000 people.

• Mount Pelee:

• The deadliest eruption in the 20th Century was Mount Pelee on the Caribbean island of Martinique. On May 2nd, 1902, the rivers were filled with boulders and trees from the mountain and the air was contaminated with sulphur.
• The eruption produced a tsunami that flooded the city. One side of the volcano collapsed, releasing boiling water and mud into the sugar farms, killing at least 29,000 people.

• Santa Maria:

• Before its eruption in 1902, the Santa Maria volcano located in Guatemala had been dormant for 500 years.
• 6000 people were killed by the eruption which released 5.5 cubic kilometres of magma.  An outbreak of malaria that followed the eruption killed several more.

• Nevado del Ruiz:

• Recorded as the 2nd deadliest volcanic eruption in the 20th Century, the Nevado del Ruiz eruption in 1985 killed at least 23,000 people.
• The Nevado del Ruiz is the northernmost volcano in the Andean volcanic belt, located in Tolima, Colombia. The eruption was Colombia’s worst natural disaster. It is estimated to have resulted in losses of 1 Billion Dollars.

• Mount Pinatubo:

• The Mount Pinatubo eruption was one of the largest volcanic eruptions of the 20th century. On 15th June, 1991, the volcano erupted, creating an ash cloud that rose 35 kilometres into the air.  
• The eruption spewed nearly 20 million tonnes of Sulphur Dioxide into the atmosphere, causing global temperatures to plummet.
• While 722 people were killed, the eruption left more than 200,000 people homeless.

Apart from these, there are several other recorded eruptions:

1. AD 79: Mount Vesuvius in Italy
2. Toba Lake in northern Sumatra is the world’s largest active volcanic caldera. The volcanic eruption that resulted in the formation of lake Toba 74,000 years ago is known to have been by far the biggest eruption of the last 2 million years.
3. 450 AD: Ilopango in El Salvador (This is one of the largest volcanic eruptions in the last 200,000 years). This eruption was so large that the skies were filled with ash and dust for more than a year.
4. The United States Yellowstone National Park is an active volcano which last spewed volcanic ash 6,40,000 years ago.

Volcanoes: Air Safety Hazard

• Volcanic eruptions are not just dangerous for nearby settlements. The volcanic ash is a major air safety hazard as well.
• There have been several incidents of volcanic ash, causing damage to aircraft. However, none have been catastrophic. Some like the 2010 volcanic eruption in Iceland disrupted over 1,00,000 flights and had millions of passengers stranded.
• Being hard and abrasive, volcanic ash is one of the most significant hazards posed by volcanic eruptions to aircraft passing through.

• Volcanic ash causes wear and tear to propellers and turbocompressor blades.
• It scratches cockpit windows, impairing visibility
• Ash contaminates fuel and water systems
• Ash can also contaminate the cabin and damage avionics
• This causes engine failures leading to air crashes
• For example, in 1982, a British Airways flight from Malaysia to Australia was affected by volcanic ash. All four of its engines failed. However, the engines of the flight started working again after the aircraft dropped from 37000 feet to 12000 feet after the molten ash that had clogged the engine started to solidify and break off.
• A similar incident occurred in December 1989 to the KLM flight 867 en route from Amsterdam to Tokyo. The aircraft was forced to make an emergency landing in Alaska when all four of its engines failed as it flew through a thick cloud of volcanic ash.
• In 1991, Volcanic Ash advisory centres were set up across the world for liaison between meteorologists, volcanologists, and the aviation industry.  
• In April 2010, the volcanic eruption in Iceland triggered concerns of volcanic ash damaging aircraft engines, as per data provided by the London Volcanic Ash Advisory Centre. This led to the controlled airspace of many European countries being closed, resulting in the largest air traffic shut down since World War II.
• The closure caused millions of passengers to be stranded, not only in Europe, but across the world. As per the IATA, the Airline industry worldwide lost $ 200 million a day during the disruption. IATA stated that the total loss for the airline industry was around $1.7 billion. 107,000 flights were cancelled between 15th-23rd April, 2010. This accounted for 48% of total air traffic and roughly 10 million passengers.

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