Analysis of 2012 M8.6 Indian Ocean earthquake coseismic slip model based on GPS data

Abstract

The CGPS (Continuous Global Position System) data of Sumatran GPS Array (CGPS) and Indonesian Geospatial Agency (BIG) in Sumatra are processed to estimate the best fit coseismic model of 2012 M8.6 Indian Ocean earthquake. For GPS data processing, we used the GPS Analysis at Massachusetts Institute of Technology (GAMIT) 10.5 software and Global Kalman Filter (GLOBK) to generate position time series of each GPS stations and estimate the coseismic offset due to the Earthquake. The result from GPS processing indicates that the earthquake caused displacement northeast ward up to 25 cm in northern Sumatra. Results also show subsidence at the northern Sumatran while the central part of Sumatra show northwest direction displacement, but we cannot find whether the subsidence or the uplift signal associated to the earthquake due to the vertical data quality. Based on the GPS coseismic data, we evaluate the coseismic slip model of Indian Ocean Earthquake produced by previous study [1], [2], [3]. We calculated coseismic displacement using half-space with earthquake slip model input and compare it with the displacement produced form GPS data.