Long Continuous Deformation during 2008-2012 Sumatra Earthquakes Using DINSAR and GPS

Abstract:

Indonesia located in three tectonic plates. This situation caused many earthquakes and long continuous movement of plate tectonics. The island which has big tectonic movement phenomena was Sumatra Island. We monitored long deformation process during interseismic and coseismic of three earthquakes in this Island. The three earthquakes were Mentawai 2008, Padang 2009 and North Sumatra 2012 earthquakes. We used Differential Interferometric Synthetic Aperture Radar (DINSAR) and Global Positioning System (GPS) satellite in order to monitor the displacement. We used GAMIT software for GPS and open source software ROYPAC for DINSAR. Sumatra GPS Array (SUGAR) Networks were used to analyze the displacement rate.

The result of displacement was very different year to year, Mw 7.6 Padang earthquake had 15.8 cm up and caused subduction zone of trench Sumatra movement about 1.8 cm to 7 cm up. The displacements was continued by Mw 7.7 Mentawai earthquake 2008. We monitored intersesismic, coseismic and postseismic phase. Coseismic phase was 0.222m in horizontal direction and 0.1415 m in vertical direction (SLBU station). The interseismic phase was smaller about 0.118 m in BSAT stations (south east direction). The biggest deformation was detected during interseismic and postseismic North Sumatra 2012 earthquakes with deformation 0.300-3.00 meter.