Volcanic eruption in Indonesia’s Mount Sinabung.

  Aug 17, 2020

Volcanic eruption in Indonesia’s Mount Sinabung.

Q. What is the news?

A. Indonesia’s Mount Sinabung volcano erupted recently, sending a column of ash and smoke more than 16,000 feet into the air. The volcano became active in 2010, erupting after nearly 400 years of inactivity. The latest eruption spewed 5000-metre high column of ash and smoke into the air, with ash covering three districts and darkening the sky.

Q. What are few stats related to volcano eruptions globally? 

A. According to the National Museum of Natural History (NMNH), USA, generally, there are about 20 volcanoes actively erupting every day. As per the weekly volcanic activity report prepared by The Smithsonian and US Geological Survey’s (USGS) Volcano Hazards program, for the week ending August 4, 2020, there were 17 volcanoes across the world with continuing eruptions. As per USGS, there are about 1,500 potentially active volcanoes worldwide.

Q. Why Volcanos often erupt in Indonesia? 

A. Indonesia is home to many active volcanoes, due to its position on the “Ring of Fire”, or the Circum-Pacific Belt, which is an area along the Pacific Ocean characterized by active volcanoes and frequent earthquakes. The Ring of Fire is home to about 75 per cent of the world’s volcanoes and about 90 per cent of its earthquakes.

Q. What is “Ring of Fire”?

A. The Ring of Fire (also known as the Rim of Fire or the Circum-Pacific belt) is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur. In a large 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and plate movements. It has 452 volcanoes (more than 75% of the world's active and dormant volcanoes). About 90% of the world's earthquakes and about 81% of the world's largest earthquakes occur along the Ring of Fire.

About the current eruption:

According to a report in the Jakarta Post, recent eruption was the third since past week, with the volcano spewing 5000-metre high column of ash and smoke into the air, followed by another eruption that produced a 2000-metre high column.

The ash from explosion covered three districts and “turned the sky dark”. More eruptions are likely in the coming days.

Q. What are the recent eruptions?

A. The volcano, which is situated in North Sumatra, has been active since 2010.

Another eruptive phase for the volcano began in September 2013, which continued uninterrupted until June 2018, according to information maintained by the National Museum of Natural History’s Global Volcanism Program. During the 2018 eruption, the volcano released ash 5-7 km into the air, coating villages.

Q .Why do volcanoes erupt?

A. A volcano can be active, dormant or extinct. An eruption takes place when magma (a thick flowing substance), formed when the earth’s mantle melts, rises to the surface. Because magma is lighter than solid rock, it is able to rise through vents and fissures on the surface of the earth. After it has erupted, it is called lava.

Not all volcanic eruptions are explosive, since explosivity depends on the composition of the magma. When the magma is runny and thin, gases can easily escape it, in which case, the magma will flow out towards the surface. On the other hand, if the magma is thick and dense, gases cannot escape it, which builds up pressure inside until the gases escape in a violent explosion.

Q. When do volcanic eruptions become dangerous?

A. According to the US Centers for Disease Control and Prevention (CDC), the most common cause of death from a volcano is suffocation, making people with respiratory conditions such as asthma and other chronic lung diseases especially susceptible. People living in areas close to the volcano, or in low-lying areas downwind, are also at higher risk in case of an explosion, since the ash may be gritty and abrasive and small ash particles can scratch the surface of the eyes.

Further, volcanic eruptions can result in additional threats to health such as floods, mudslides, power outages, drinking water contamination and wildfires.

Lava flows, however, rarely kill people, since they move slowly, giving enough time to escape. One reason why volcanic eruptions can be dangerous in places such as Indonesia, Guatemala and the Philippines is that in these countries, large populations are packed on and around volcanoes.