Analysis of submarine landslide potential that can trigger tsunami based on seismic reflection interpretation

Abstract

The megathrust at the west part of Sumatera can produce a lot of earthquakes. Several earthquakes in Sumatera that occurred from 2004 to 2007 raised tsunami with various heights. The high tectonic activity in this area can trigger landslides in the ocean which may lead to tsunami. Therefore, research about seabed landslides needs to be done in this zone. The study identified the seabed geological structure from 2D seismic section in the east part of Siberut Island. The seismic section was generated from seismic processing of Seismic Line-05 (AA’). The seismic data were acquired using LIPI Baruna Jaya VIII research vessel on the Pre-Tsunami Investigation of Seismic Gap (PreTI-Gap) marine expedition in 2008. Seismic section interpretation shows the presence of backthrust on this seismic line. The bathymetry data from the Geospatial Information Agency and marine survey are used to make bathymetry map, bathymetry charts, and slope map. Analysis using 2D seismic section, bathymetry data, and slope map shows the steep zones at 3–5 km and at 15–16 km from the south west edge of Seismic Line-05 (AA’) with 180 m and 300 m bathymetry drop, respectively. These steep zones must be watched because they can trigger submarine landslides and tsunami.