The Sumatra-Andaman subduction zone, which runs parallel to the west side of Sumatra and the Mentawai Islands (see map below) is the most seismically active region in the world, and in the last decade has endured multiple massive earthquakes that caused tsunamis with death tolls in the hundreds of thousands, including the 2004 Boxing Day tsunami that claimed more than 230,000 lives. The science team will assess their geological signatures, and look for clues as to what seafloor deformations might spawn tsunamis. The data from this expedition could enable forecasting of what to expect during a future earthquake.
The team found many active faults at the Wharton Basin with different orientations, suggesting that the whole area is deforming on different scales. This area was the site of the largest intra-plate earthquake ever known, and the strongest aftershock. It was such a powerful event that before it, scientists did not even believe such an earthquake was possible. West of Siberut Island lies the Mentawai Gap, a locked patch of the Sumatra-Andaman subduction zone that has not released its stored energy for over 200 years. This leads the experts to believe that a powerful earthquake will eventually originate here. Seismic images acquired during the expedition showed active faults near the Sunda Megatrench, both on the subducting and the overriding plate. A detailed analysis of this data will allow the scientists to better constrain the nature of a tsunami produced by an earthquake in this region.
Fledermaus is an interactive 4D geo-spatial processing and analysis tool. The recently released Version 7 added a fully integrated time reference allowing users to work in a true 4D space and time environment.
You can view the latest videos from this expedition here.
Content for this story is courtesy of Schmidt Ocean Institute, Institute of Physics of Paris Globe, Indonesia Institute of Sciences (LIPI), Earth Observatory of Singapore.
