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Explained: Mount Sinabung’s recent volcanic eruption, why it happened and who are at risk

The latest eruption spewed a massive column of volcanic ash and smoke 3,000 metres into the sky.

By: Explained Desk | New Delhi |
Updated: May 11, 2021 8:31:42 am
Mount Sinabung releases volcanic ash during an eruption on Friday. (AP)

Indonesia’s Mount Sinabung, located in the North Sumatra province, erupted on Thursday, belching a massive column of volcanic ash and smoke 3,000 metres (3 km) into the sky.

The volcano had erupted in March as well, sending a cloud of hot ash into the sky. This was the first time it erupted since August 2020 when the volcano sent a column of ash and smoke more than 16,000 feet into the air. The volcano has been active since 2010 when it erupted after nearly 400 years of inactivity.

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Indonesia is home to many active volcanoes owing to its location in the “Ring of Fire” or the Circum-Pacific Belt — an area along the Pacific Ocean characterised 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 earthquakes also occur here.

Mount Sinabung’s recent eruptions

The ash from August’s explosion covered three districts and “turned the sky dark”, the Jakarta Post reported. As such, thousands of people were also displaced.

According to the National Museum of Natural History, USA, there are about 20 volcanoes actively erupting everyday around the world. As per the weekly volcanic activity report prepared by The Smithsonian and US Geological Survey’s Volcano Hazards program, for the week ending August 4, 2020, there were 17 volcanoes across the world with continuing eruptions.

As per Xinhua news agency, the volcanic eruption of Thursday morning lasted for about 319 seconds or about 5 minutes. Indonesia’s Volcanology and Geological Hazard Mitigation Centre has advised people to not go into the danger zone — a 3 km radius of the volcano — and has urged them to wear a mask while venturing out to stay protected from contaminated particles that are current suspended in the air, the Weather Channel reported.

The volcano has been active since 2010. The eruptive phase began in September 2013 and continued uninterrupted till June 2018, according to the National Museum of Natural History’s Global Volcanism Program. In 2018, the volcano released ash 5-7 km into the air, coating villages. According to the Weather Channel, when the volcano had erupted in 2014, it killed 16 people and displaced thousands and in 2016, nine more people had died because of the eruptions.

So, why does a volcano erupt?

Basically, there are three types of volcanoes — active, dormant or extinct. An eruption takes place when magma (a thick flowing substance), that is formed when the earth’s mantle melts, rises to the surface. As magma is lighter than rock, it is able to rise through vents and fissures on the surface of the earth. Following eruption, the magma 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 such cases, the magma will flow out towards the surface. However, if the magma is thick and dense and gases cannot escape it, it builds up pressure inside resulting in a violent explosion.

Who are at risk from these eruptions?

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 susceptible.

People living close to the volcano or in low-lying downwind areas are also at higher risk in case of an explosion since the ash may be gritty and abrasive and small 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.

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Lava flows, however, rarely kill people since it moves very slowly, giving enough time to escape. In an interview in 2018, geologist Gail Mahood from Stanford noted that a reason why volcanic eruptions become dangerous in countries like Indonesia, Guatemala and the Philippines as people live very close to the volcanoes owing to its large population.

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