Nanyang Technological University (NTU) scientists at its Earth Observatory of Singapore (EOS) will be leading an international team to Sumatra, Indonesia to investigate the cause of tsunamis.
This month-long expedition aims to assess the risk of tsunamis caused by earthquakes in the region by mapping the ocean floor where the tectonic plates meet each other.
The research project is done in partnership with the Schmidt Ocean Institute on board its research vessel Falkor, and is jointly led by NTU’s EOS, France’s Institut de Physique du Globe de Paris (IPGP), and the Indonesian Institute of Sciences (LIPI).
The 83 metre-long oceanographic vessel, Falkor, will depart Singapore on Saturday, 23 May 2015 on its way to a region in the Indian Ocean off the west coast of Sumatra, known to have produced tsunami-spawning earthquakes.
The international scientific team consists of more than 10 scientists from all three research institutes, in addition to the crew on board the Falkor.
Officially known as The Mentawai Gap Tsunami Earthquake Risk Assessment (MEGA-TERA) expedition, it will target the region west of Siberut Island, near the city of Padang, identified as the Mentawai Gap. This is the only area of the geologically active Sumatra-Andaman subduction zone that has yet to have a large earthquake in the last 200 years.
Renowned NTU geologist and seismologist, Professor Kerry Sieh who is the Director of EOS, said this international expedition will yield many important insights into the study of undersea earthquakes and their ability to cause tsunamis.
The Asian region is a hotbed of tectonic activity and over the last few years, we have seen many natural disasters arising from earthquakes and tsunamis, such as those in Aceh in 2004, Chile in 2010 and Tohoku Japan in 2011, said Prof Sieh, who developed new ideas and techniques to understand the recurrence of earthquakes and fault behaviour that has changed how scientists study earthquakes.
With greater knowledge of how tsunamis are caused, our scientists would be able to build enhanced simulation models which allow us to better prepare for such events which will happen not just in Asia, but other parts of the world.
Professor Paul Tapponnier from EOS, one of the chief scientists in charge of this expedition, said the team aims to uncover the mechanisms that cause tsunamis.
We know that the plates in the Sumatra-Andaman subduction zone move towards each other at about four centimetres a year, which results in earthquakes roughly every 250 years, said Prof Tapponnier, a world-renowned tectonics expert.
An example of such an earthquake was the 2004 Indian Ocean earthquake and tsunami which happened along the same fault line. If we have better knowledge of the ocean floor and understand the mechanisms that cause tsunamis, we can help people to better prepare for the eventualities.
In the Padang area alone, there are over 500,000 people residing less than five metres above sea level and there are over seven million people living along the central and southern coasts of Sumatra and the Mentawai Islands.
Victor Zykov, Director of Research for SOI is excited about the collaboration. We look forward to carrying out the MEGA-TERA project in collaboration with EOS, LIPI, and IPGP. Falkor’s shipboard mapping echo sounders will be used to acquire high definition maps of seafloor deformations that resulted from recent earthquakes. This information is critical for the understanding of the origins of earthquakes and tsunamis in this region, and for the development of evacuation routes to help save human lives should similar calamities occur in the future.”
Professor Satish Singh, a visiting professor at EOS and a theoretical seismologist from IPGP in France, will be co-leading this voyage.
In our previous paper published in Geophysical Research Letters on the 2010 Pagai earthquake, just after the 2011 Tohoku earthquake and tsunami happened in Japan, we proposed a theory on how undersea earthquakes can cause tsunamis, said Prof Singh, who has been on over 25 ocean expeditions to understand underwater earthquakes.
We know from past events that small earthquakes can cause large tsunamis while large earthquakes could result in a small or no tsunami. This depends on several factors such as the depth of the seabed and whether the earthquake comes to the front, breaking ground and thus displacing sea water.
Over the next 30 to 40 days, we will use advanced deep-sea mapping technologies to study the seafloor subduction zone at depths of 5,000 metres or more, which is not very well studied and understood in this region.
Dr Haryadi Permana, Director of Research Centre for Geotechnology from LIPI, said: With better knowledge on tectonic behaviour, we can prepare better to reduce risk from mega-earthquakes. We do not want a horrific disaster like in Aceh to happen again in Padang or other towns that we have identified in risk of mega-earthquake and tsunamis.
All information and data obtained from this expedition, such as the high-resolution maps of the ocean seabed, will be shared publically with other scientists and research organisations.
The Schmidt Ocean Institute supports oceanographic research and technology development at sea by providing scientists with access to the research vessel Falkor through an open-call for research proposals. This MEGA-TERA expedition will be Falkor’s fifth research project to sail this year.