Towards a Better Understanding of Inter-seismic Deformation in the Mentawai Seismic Gap by Establishing a Denser GPS Network in West Sumatra
Abstract
Over the last decade, the Sumatran GPS Array (SuGAr) network has been established to monitor strain accumulation along the Sumatra Subduction Zone (SSZ). This network has successfully detected inter-seismic, co-seismic and post-seismic deformations associated with a large number of great earthquakes on the SSZ. Based on the GPS data, currently, the Mentawai patch of the SSZ is locked and accumulating stress on the fault interface. However, the network is mainly located in the Mentawai Islands. In Padang area and around, West Sumatra, only few GPS stations had been installed. Reliable model with a better resolution in particular at the deeper part of the SSZ requires large amounts of GPS data sets. This model will help us to a better understanding of inter-seismic deformation in the region. Through PEER project, we have installed 30 sites of low cost campaign GPS monument to collect information of crustal deformation on main land of West Sumatra. We have conducted three GPS campaign surveys on this segment (3-4 days of measurement for each occupation sites). We combined our GPS data sets with SuGAr network for processing using GAMIT 10.61. GPS vector deformations obtained are referenced to the Sunda Block in order estimate inter-seismic deformation due to the Indo-Australia plate movement. We obtained that the inter-seismic deformations are consistent with regional tectonic setting where the vector deformations are dominated by trench perpendicular fault motion. The campaign sites are still too premature to be used for a precise estimation of inter-seismic deformation, but we conclude that new sites can provide a better resolution for modeling intra-plate coupling for the Mentawai patch along the SSZ. Our new sites can improve the resolution model up to 80% in the deeper part of plate interface. In the future, to obtain better understanding inter-seismic deformation of the Mentawai seismic gap, we will continue to conduct more GPS campaign surveys.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.G23C0608L
- Keywords:
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- 1209 Tectonic deformation;
- GEODESY AND GRAVITYDE: 3040 Plate tectonics;
- MARINE GEOLOGY AND GEOPHYSICSDE: 7230 Seismicity and tectonics;
- SEISMOLOGYDE: 8107 Continental neotectonics;
- TECTONOPHYSICS