Seismogenic fault and tectonic significance of 1996 Karakoram Pass earthquake (Ms 7.1) based on InSAR

Abstract

Due to hard observation condition of the western Tibet region, the slip behaviors of the Ms7.1 Karakoram Pass earthquake occurred in Hetian, Xinjiang on November 19, 1996 remains unclear. Using ERS 1/2 SAR data and InSAR technique, we obtain the co-seismic deformation of the earthquake. The north and south deformation areas show asymmetric pattern, with the maximum LOS displacement of the southern part approximately 24.6 cm, and the maximum LOS displacement in the northern part approximately − 18.5 cm. Nonlinear and linear inversion algorithms are used to determine the geometric parameters and slip distribution of the earthquake fault. Our results show that the co-seismic displacement is dominated by deformation fields are clearly visible sinistral strike-slip accompanied by a small amount of normal slip component. The co-seismic slip occurred between 0 and 18 km at depth. The maximum slip is ~ 81 cm, occurring at a depth of 8.5 ± 0.5 km at (35.36°N 78.03°E), indicating a shallow event with a moment magnitude of Mw 6.5. The seismogenic fault is a secondary fault in the Karakoram fault zone with strike 96°, dip 84°, and rake – 24°. This earthquake shows that the Karakoram fault zone undergoes a complex tectonic deformation process, with central part of the fault zone showing minor tensional deformation behaviors[Figure not available: see fulltext.].