Present-day tectonic activity along the central section of the Altyn Tagh fault derived from time series InSAR

Abstract

The Altyn Tagh Fault (ATF) is a large-scale complex tectonic system. In this study, the present-day crustal deformation of the central section of the ATF (90.8°E−91.58°E) was obtained using 14 images on a descending track acquired between 2007 and 2010 from Advanced Land Observing Satellite (ALOS). To improve the accuracy of the interferograms, ALOS World 3D–30m (AW3D-30)Digital Surface Model (DSM) from the Japan Aerospace Exploration Agency was used in Small Baseline Subset (SBAS) Interferometric Synthetic Aperture Radar (InSAR) processing. The Line of Sight (LOS) deformation map show that there is an obvious zoning feature. With the main ATF as the boundary, the north block is concentrated around −35∼ −60 mm, and the south block is concentrated around −9 ∼ 11 mm. Based on the InSAR velocity map, we inverted for the strike-slip rate and locking depth of the fault using the two-dimensional strike-slip fault buried-dislocation model. The inversion results for the strike-slip rate at three selected cross-section locations perpendicular to the ATF were 6.1 mm/a, 5.3 mm/a and 7.9 mm/a from west to east; the corresponding locking depths were 9.5 km, 6.8 km and 12.3 km from west to east. The location and trend of the fault obtained by inversion are coincides with the Xorkol seismic belt.