Indonesian Tsunami - October 2010

| More

This page was funded by GA membership subscriptions - please consider supporting our work by joining today


On Monday 25 October 2010 at 9:42pm local time, an 7.7 magnitude earthquake struck the Mentawai Islands of Indonesia sending a 2-3 metre (6-10 foot) tsunami into the southern island of Pagai Selatan.

At the time of writing more than 400 people are confirmed dead and several hundred are missing (BBC, 29.10.10). Thousands of families are displaced and relief efforts are being hampered by heavy rain and high tides.

Indonesia is also struggling with the devastation caused by the eruption of Mount Merapi on 26 October in central Java, which killed more than 30 people.

The GA offers its condolences to everyone affected by these events. We hope that this page can help students understand what happened and raise awareness of disaster management and the ongoing issues affecting the people in this region.

Pacific Ring of Fire

The earthquake was caused by plate movements in the area known as the Pacific Ring of Fire, a highly volatile region which circles the Pacific Ocean. Around 80% of the world's earthquakes occur around this rim (National Geographic).

The US Geological Survey provided the following summary of the tectonic activity which led to the earthquake and subsequent tsunami:

The Pulau Pagai Selatan, Sumatra earthquake of October 25, 2010 occurred as a result of thrust faulting on or near the subduction interface plate boundary between the Australia and Sunda plates. At the location of this earthquake, the Australia Plate move north-northeast with respect to the Sunda plate at a velocity of approximately 57-69 mm/yr. On the basis of the currently available fault mechanism information and earthquake depth it is likely that this earthquake occurred along the plate interface. (US Geological Survey, 29.10.10)

Sumatra Subduction Zone

The earthquake occurred in the Sumatra Subduction Zone which is an area where the Australian and Sunda (Eurasian) plates collide.

The Mentawai Islands were formed from sediments scraped off the top of the Australian plate as it moves below the Sunda plate. This same tectonic action was responsible for the earthquake.

When the build up of stress at the plate boundary causes rock to fracture, the plates grind past each other and release energy in the form of an earthquake.

This helpful explanation of tectonic activity in the Sumatra Subduction Zone was prepared by the NASA Earth Observatory following an earthquake in the region during April 2010. The article is accompanied by a clear diagram showing plate boundaries and islands.

Sumatra Subduction Zone - NASA Earth Observatory

A similar report and diagram have also been created for the 25 October earthquake.

Other links

Indonesian Earthquake Summary Poster (PDF, external website) - USGS
Indonesian Earthquake Maps (PDF, external website) - ReliefWeb

Indonesian Tsunami - News Reports

1 November 2010 - SurfAid International Program Manager Tom Plummer filmed this video clip in what used to be the village of Gogoa, on the island of Pagai Utara:

Visit the SurfAid International website for daily updates and photographs.


Indonesia tsunami relief slowed by bad weather - BBC 29.10.10 (article and video)
In pictures: Tsunami relief - BBC 28.10.10
'No alert' in Indonesian tsunami - BBC 27.10.10
Footage shows tsunami devastation - BBC 27.10.10 (video)

Channel 4 News

Tsunami death toll rises in Indonesia - Channel 4 News 28.10.10 (article and video)


Indonesian tsunami warning system 'did not cover remote islands' - Guardian 28.10.10 (article and video)
Indonesia hit by tsunami and volcanic eruption - Guardian 27.10.10 (images)


Picture Gallery: Indonesia Tsunami - Telegraph 29.10.10
Indonesia tsunami death toll rises - Telegraph 29.10.10 (video)

Personal Stories

Some eye-witness accounts and personal stories are emerging from tsunami survivors and aid workers:

We're just glad to be alive - BBC 27.10.10
Indonesian tsunami survivor tells of terrifying wall of water - Guardian 27.10.10

It's also well worth having a look at Joey L's Blog which documents the time he spent with the Mentawai people in 2009. During Joey's visit he experienced several minor earthquakes and the website includes a description of a discussion with his hosts about the causes of the quakes, their fears and beliefs.

Disaster Relief: Student Activities

These activity ideas help students consider the geographical and logistical problems facing aid workers and how they would deal with the relief effort.

Reaching the Islands

Aid agencies are experiencing numerous difficulties in reaching the devastated villages. Ask students to think about the geography and infrastructure of the Mentawai Islands and the nature and scale of the disaster before considering the problems aid workers may be facing.

Background information: Introducing the Mentawai Islands

Problems aid agencies are facing include:

  • Heavy rain - leads to choppy sea and poor visibility for boats and helicopters
  • Rough sea - makes it dangerous and difficult for boats to sail
  • Coral reefs - making sea access to some villages even more dangerous
  • Space to land - helicopters are struggling to land in the devastated villages
  • Lack of boats - many have been washed away or destroyed
  • Communications - bad weather is making mobile and satellite communications very difficult
  • Poor roads - trucks are unable to drive to outlying villages that are only accessible by foot or by sea
  • Health facilities - hospitals are basic, many are badly damaged, and there are not enough health care professionals to deal with the number of casualties
  • Volcanic eruption - aid is also required elsewhere in Indonesia following the eruption of Mount Merapi
  • Funds - money is needed for food, shelter, clothing and medical supplies

Once the issues have been identified, ask students to think about how some of these problems could be overcome.

  • How could aid agencies get around some of these difficulties?
  • Who is in greatest need of aid? How should the help be prioritised?
  • What would you do to help people in outlying villages?

Response Plan

Agencies involved in the relief work included:

SurfAid International
New Zealand Aid Programme
World Vision

Students could investigate these websites to find out how the aid agencies are dealing with the disaster before coming up with their own response plan. Make sure they consider:

  • Adequate assessment of the situation
  • Potential hazards
  • What to send to the islands
  • Funding
  • Longer term needs

SurfAid International have posted an annotated map on their blog showing the villages assessed so far. This is accompanied by detailed information about the assessments, what is needed in each area, problems they've been facing and how their teams are responding.

GIS Decision-Making Exercise

Elsewhere on the GA website is a Sumatra GIS Exercise which is based around the relief response to an earthquake which happened in 2009. You could use this decision-making activity as it is, or adapt it to suit the 25 October tsunami.

Mount Merapi Eruption: Student Activity

The day after the tsunami Mount Merapi in central Java erupted, killing 32 and leading to the evacuation of thousands. It erupted again on 29 October prompting fears of further tectonic activity.

  • What else could happen as a result of the volcanic activity?
  • Are people safe to return to their homes and farms?
  • What problems could the ash and lava cause?
  • Could the volcanic eruption produce any positive outcomes?

There has been some debate as to whether the earthquake, tsunami and volcanic eruption are connected or whether it is pure coincidence that these disasters have happened within days of each other.

Coincidence? Dr Colin MacPherson, a reader at Durham University and an expert on volcanic activity in Java, said it was not feasible that the earthquake prompted the eruption... (Guardian 27.10.10)

Connected? "Volcanic eruptions that are related to stress changes following earthquakes, or due to triggering by the seismic waves, do seem to occur," Chris Goldfinger, a marine geologist at Oregon State University, said by email. "But documentation of them is spotty at best." (National Geographic 27.10.10)

Ask students to consider the evidence. What do they think?


<<< Back to Earthquake and tsunami page

Comment on this page

Comments made by GA members appear instantly and don't require security words to be entered - make sure you're logged in! Guest comments will be sent to a moderator for approval.

Join the GA

For professional journals, huge discounts on publications and CPD and online access to member only resources.

Join now
  • Become a geography examiner
  • Cambridge International Examinations
Receive our email newsletters

Sign up to our email newsletter for all the latest news and updates throughout the year.