Source model for the Mw 6.0 earthquake in Jiashi, China on 19 January 2020 from Sentinel-1A InSAR data

Pengfei Yu,Zhaosheng Nie,Jie Li,Zhige Jia,Dijin Wang,Xuejun Qiao,Wei Chen,Wei Xiong

doi:10.1186/s40623-020-01300-4

Pengfei Yu, Zhaosheng Nie + Show 6 more

Open Access

https://doi.org/10.1186/s40623-020-01300-4

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Abstract

On January 19, 2020, an Mw 6.0 earthquake occurred in Jiashi, Xinjiang Uygur Autonomous Region of China. The epicenter was located at the basin-mountain boundary between the southern Tian Shan and the Tarim Basin. Interferometric Synthetic Aperture Radar (InSAR) is used to obtain the coseismic deformation field from both ascending and descending Sentinel-1A satellite images of the European Space Agency. The results showed that the coseismic deformation is distributed between the Kalping fault and the Ozgertaou fault. The earthquake produced significant deformation over an area of approximately 40 km by 30 km. The maximum and minimal displacements along the line of sight (LOS) are 5.3 cm and − 4.2 cm for the ascending interferogram and are 7.2 cm and − 3.0 cm for the descending interferogram, respectively. The fault geometry from the Multi peak Particle Swarm Optimization computation indicates that the seismogenic fault is a shallow low-dipping planar fault that is 4.58 km depth underground. The finite slip model inverted by the Steepest Descent Method implies that the rupture is dominated by a thrust fault. The slips are concentrated in a depth of 5–7 km with a maximum slip of 0.29 m. The estimated total seismic moment is 1.688 × 1018 Nm, corresponding to a magnitude of Mw 6.1. The seismogenic fault is the Kalping fault which has a listric structure. The coseismic deformation only occurred on the décollement layer and did not involve the ramp segment. The coseismic Coulomb stress changes have enhanced the stress on the deep margin of the Jiashi earthquake rupture area, indicating that there is still the possibility of strong earthquakes in this region in the future.

Highlights

An Mw 6.0 earthquake struck Jiashi (39.83° N, 77.21° E) in Xinjiang, western China on January 19, 2020 (Fig. 1a)
The focal mechanism solutions from the United States Geological Survey (USGS) and Global Centroid Moment Tensor (GCMT) indicated that the Jiashi earthquake was caused by a thrust fault with a slight strike-slip (Table 1)
The epicenter of the Jiashi earthquake is located at the southern margin of the Kalpingtag thrust system (Kalping block), which is situated in the basin-mountain junction region between the south Tian Shan and the

Summary

Introduction

An Mw 6.0 earthquake struck Jiashi (39.83° N, 77.21° E) in Xinjiang, western China on January 19, 2020 (Fig. 1a). The InSAR observations of coseismic deformation are used to highlight the fault geometry and the slip model. The coseismic deformation of the 2020 Jiashi earthquake is measured with the InSAR technique using both the ascending and descending interferograms from the Sentinel-1A (See figure on page.) Fig. 1 a Distribution map of topography, fault, major historical earthquake and InSAR data in the Jiashi areas. Fault geometry optimization Based on an elastic and half-space dislocation model, a Multi peak Particle Swarm Optimization (MPSO) algorithm is used to invert for the nine fault parameters consisting of location, length, width, depth, strike, dip, rake and slip by minimizing the misfits between the observed and the model predictions (Feng 2010). The Coulomb stress changes along a profile across the southern edge of the Kalpingtag nappe show that the area below the rupture of the Jiashi earthquake is a stress-enhancing zone (Fig. 5)

Discussion

Conclusion