This article, written by Lucy Baker and Emma Poppleton (Lower Sixth), has been selected to to be published in GCSE Worldwide Magazine.

In August 2010, an Indonesian volcano erupted after being dormant for over 400 years. Mount Sinabung is located in Sumatra in Indonesia and was created by the subduction of the Indo-Australian plate under the Eurasian plate. Its location makes it part of the Pacific Ring of Fire and at 4,260m tall it is the 11th highest volcano in Indonesia.

How are Volcanoes formed?

Mt. Sinabung is situated on a destructive plate boundary where volcanoes are formed when the denser tectonic plate, in this case the Indo-Australian plate, is forced under the less dense plate, the Eurasian plate. As the plate is pushed under, the increased heat, pressure and friction causes the rock to melt to become magma. This magma rises to the surface of the crust and cools to form a volcano.

 

Plate movement around the Pacific Ring of Fire is very frequent and there are 452 active volcanoes in the area.

How do volcanoes differ?

Mt. Sinabung is a composite strato volcano made up of alternating layers of ash and lava. The sides are steep causing the pyroclastic flow to reach great speeds. Pyroclastic flow is made up of hot steam, dust, rock and ash and at over 400°c is more deadly than the lava flows. The eruptions from these types of volcano are much more violent than other types but then the violence subsides quickly whilst the lava flow continues.

 

Another type of volcano is a shield volcano which has much gentler sloping sides and less violent eruptions.

Volcano’s Eruption history

Mt. Sinabung has a very short eruption history with the last recorded eruption occurring in around 1600 and possibly in 1881. In 2010 it erupted after 400 years of dormancy, however this period of activity lasted less than a month. In comparison a similar active volcano nearby, Java’s Raung Volcano, has erupted 66 times since 1586. The first larger eruption for the volcano occurred on 15th September 2013 causing more than 3700 people to be evacuated from areas within 3km of the volcano. Later, on 5th November the volcano erupted a 7km column of ash into the air and so evacuation distance was increased. The volcano continued to be relatively active with small eruptions in late December and early January before a major eruption on the 1st February 2014. Clouds of hot ash were spewed 2km into the air and smothered surrounding villages. This eruption occurred just after residents living more than 5km away from the volcano had been allowed back to their homes.

Impacts/Effects

Economic

The thick volcanic ash produced as a result of the eruptions caused damage to many villages in the surrounding area. Many houses were destroyed as they collapsed under the weight of the ash. By Saturday 11th January 2014 the ash had also begun to blanket more villages and cities in North Sumatra because of the continuous eruptions. Consequently many farmers lost their crops, meaning that there was a very poor harvest, as a result many areas surrounding the volcano experienced food shortages and substantially increased food prices. The damage caused had a great impact on the economy of this LEDC as the crop losses equated to more than £50,000. This figure is set to rise due to the cost of rebuilding the homes and lives of those affected.

Social

Since Mt. Sinabung’s eruption in September 2013, it has claimed at least 16 lives and devastated many more. Recent counts show that an estimated 25,516 people from 32 villages in the surrounding area had taken refuge. Vast numbers of people took refuge in temporary camps and shelters, and soon the authorities began to lack food supplies and medicine, putting more lives at risk. The ash produced by the volcano also contributed to health issues as many people experienced respiratory problems.

Environmental

The eruptions also caused many environmental problems. Lava produced by Mt. Sinabung flowed into the river, contaminating the water supplies and affecting the biodiversity of the river’s ecosystem. The surrounding valleys were filled with pyroclastic material left behind after the enormous ash plumes. This material destroyed crops and many villages as it settled in the valleys. The ash plumes not only caused respiratory problems for residents, but also caused air pollution as it lingered in the atmosphere. Much of Sumatra’s wildlife was severely affected by the ash and pyroclastic material which poisoned them.

Responses

Short term

The volcano caused thousands of people to be evacuated to temporary camps and shelters e.g. converted halls that are usually used for traditional ceremonies set up by the government until it was safe for them to return. People soon realised that international aid and donations were needed as they started to see shortages of necessities such as clean water. For those who had not sought refuge or been evacuated, masks were issued by the authorities and they had to be worn at all times.

Long term

The government is now helping people to rebuild their lives and their homes. New methods such as use of tiltmeters and early warning systems are being put in place to help scientists predict when similar eruptions may occur again. This will help the government put in place sufficient protection for its people but as Indonesia is a poor country these methods are very gradually being put into practice.