Mount Merapi Eruption 2010

What caused the Mount Merapi eruption in 2010?

The Mount Merapi eruption in 2010 was caused by the subduction of the Indo-Australian plate underneath the Eurasian plate. The volcano lies on a destructive plate margin at a subduction zone, which is part of the Pacific Ring of Fire. The Mount Merapi eruption happened when the denser plate edge, the Indo-Australian plate, sunk (subducted) beneath the less dense plate edge, the Eurasian plate. When this happens, the denser plate’s movement causes an increase in the temperature and pressure, which ultimately leads to the release of water from the rocks. This results in a decrease in the melting point of the rock above and magma rising to the surface, causing eruptions.

Impacts of the Mount Merapi eruption in 2010

The 2010 Mount Merapi eruption had numerous devastating effects on the environment, economy, and people. Let’s take a look at these impacts in more detail.

Environmental impacts of the Mount Merapi eruption 2010

The ash plumes, lahars, pyroclastic flows, and sulphur dioxide released from Mount Merapi caused various short-term and long-term environmental problems, such as the destruction of ecosystems and housing and an increase in the greenhouse effect.

Ash plumes

The ash plumes from the 2010 Mount Merapi eruption reached altitudes of 18km and fell up to 30km away from the peak of the volcano. The layer of ash on the ground was 2-4cm thick and damaged 200 hectares of forest. In the long term, the volcanic ash in the atmosphere can increase the greenhouse effect by reflecting sunlight onto the earth.

A positive long-term effect of the release of ash plumes is the fertilization of soil, which can benefit the farmers in the affected area.

Lahars and pyroclastic flows

Multiple explosions with lahars and pyroclastic flows occurred between 26 October and 30 November. Cangkringan and Kemalang were the most affected areas, where rice fields, farms, infrastructure, rivers, and soil were damaged. Significant damage was even observed two years later.

Sulphur dioxide

At higher altitudes, sulphur dioxide reacts with the environment and can cause acid rain and cooling of the climate by reflecting the sunlight. A sulphur dioxide cloud 12,000-15,000m above the Indian Ocean was observed on 9 November 2010 by the Volcanic Ash Advisory Center in Darwin, Australia. However, this was not enough to create an observable difference in global temperature.

Social impacts of the Mount Merapi eruption 2010

The social impacts of the Mount Merapi eruption in 2010 included the loss of lives, homes, livelihood, forced evacuation, and increased physical and psychological health problems.

Health

Many of those who evacuated stayed in refugee camps where the public toilets were unhygienic. Additionally, the sulphur dioxide released from the eruption caused irritation to human skin, eyes, and respiratory tracts. Many people at the refugee shelters suffered from headaches, acute respiratory infection, and high blood pressure.

Livelihood

A lot of the refugees were farmers who lost their livelihoods because the ash from the volcanic eruption caused damage to crops. This also made people fearful of food shortages. Many were forced to become miners and sell sand from the eruption or take up other jobs initiated by the government, such as cleaning up the volcanic ash. However, some suffered from psychological trauma from the eruption, which made it more difficult for them to work.

Psychological distress

A survey was conducted two years after the disaster to determine the psychological distress of those affected in Cangkringan and Pakem. It demonstrated that those living in the Cangkringan district experienced the most distress in relation to the environmental impact of the eruption.

Economic impacts of the Mount Merapi eruption 2010

The total economic impact from the Mount Merapi eruption in 2010 was estimated at £450 million. This was mainly due to the impact on farming, tourism, and manufacturing.

Farming and plantation

As we mentioned above, many farmers lost their livelihoods due to the ash from the eruption. There was significant damage to rice, fruits, and vegetables, and as a result, the economic loss from agriculture was estimated at £13 million.

Tourism and flights

As you can imagine, the eruption had a big impact on tourism. Compared to the previous year, the number of tourists in 2010 dropped by approximately 30 percent for domestic tourists and 70 percent for international tourists. Certain flights that travelled through the ash clouds also experienced engine failure. Around 2500 flights were cancelled for safety reasons.

Although tourism has increased since the eruption, it has been impacted by a decreased level of trust and security.

Responses to the Mount Merapi eruption of 2010

Mount Merapi is an active volcano, meaning the people of Java have experienced several eruptions over the years. So, what mitigation (preventative) strategies existed before the 2010 Mount Merapi eruption, and what changed after the eruption? Let’s have a look.

Mitigation strategies before the Mount Merapi eruption in 2010

The main mitigation strategies aimed at reducing the potential impact of volcanic eruptions have largely relied on monitoring and warning.

Seismological monitoring

A mechanical seismograph was installed 9km from Mount Merapi in 1924. A tiltmeter (a device that measures small variations in the vertical level) is also used to monitor any changes in the volcano. Observations at the beginning of 2010, such as earthquakes and changes in the dome, suggested that the volcano was going to erupt.

Fig. 4 - Tiltmeters measure variations in the vertical level

Evacuation drills

Police and the military were prepared to provide trucks and buses ordering people to leave. Temporary shelters were also ready for evacuees.

Indigenous warning signs

Many communities rely on their traditional warning signs of volcanic eruptions. This includes ash plumes, the movement of monkeys and other animals down the volcano, minor earthquakes, and lightning storms from the ash. Many people also rely on their spiritual connection to the volcano, so if they don’t see these signs, they are not likely to listen to advice to evacuate based on scientific monitoring.

Mitigation strategies after the Mount Merapi eruption in 2010

A significant reason for the consequences of the Mount Merapi eruption in 2010 is the forgotten danger of living next to the volcano. Previously, many people would ignore the smoke coming from the volcano. Civilians have now become more reactive, and the government and non-governmental organizations have also implemented strategies to limit the future consequences of eruptions.

Awareness

People have now become more aware of the potential dangers of living near a volcano and pay more attention to possible eruptions. Training has also been given to communities for more organised evacuation.

Relocation

The government relocated 2500 families to safer areas. However, some people are still hesitant to move due to limited education, the requirement to adapt to new jobs, and not being directly affected by the eruptions in 2010.

Enhanced warning system

Many people have now been given handheld radios, which can give them updated information about the volcano. Representatives are also given information by the government monitoring centres, which speeds up the spreading of information. This is an improvement from the previous methods, which were slow and involved various sources of information.

Improved infrastructure

Roads and bridges have been improved for a smoother evacuation process.

Mount Merapi facts

Here are some interesting facts about Mount Merapi:

• Mount Merapi means Mountain of Fire in Indonesian.
• It is a stratovolcano, meaning it has layers of lava and ash.
• It has been erupting since the sixteenth century and is Indonesia’s most active volcano.
• Over 11,000 people live on the sides of Mount Merapi.
• During the 2010 eruption, the volcano’s shape changed: it lost 38m in height.