Abstract
Abstract. On 14 April 2010, an Mw = 6.9 earthquake occurred in the Yushu county of China, which caused ~3000 people to lose their lives. Integrated with the information from the observed surface ruptures and aftershock locations, the faulting pattern of this earthquake is derived from the descending wide-swath and ascending strip mode PALSAR data collected by ALOS satellite. We used a layered crustal model and stress drop smoothing constraint to infer the coseismic slip distribution. Our model suggests that the earthquake fault can be divided into four segments and the slip mainly occurs within the upper 12 km with a maximum slip of 2.0 m at depth of 3 km on the Jiegu segment. The rupture of the upper 12 km is dominated by left-lateral strike-slip motion. The relatively small slip along the SE region of Yushu segment suggests a slip deficit there. The inverted geodetic moment is approximately Mw = 6.9, consistent with the seismological results. The average stress drop caused by the earthquake is about 2 MPa with a maximum stress drop of 8.3 MPa. Furthermore, the calculated static Coulomb stress changes in surrounding regions show increased Coulomb stress occurred in the SE region along the Yushu segment but with less aftershock, indicating an increased seismic hazard in this region after the earthquake.
Highlights
On 14 April 2010, a devastating (Mw = 6.9) earthquake struck the Yushu county, south area of Qinghai Province, China
We combine Phase Array Lband Synthetic Aperture Radar (PALSAR) Interferometric synthetic aperture radar (InSAR) data collected by the Advanced Land Observation Satellite (ALOS) with both ascending strip mode and descending wide-swath mode, geological field observations, and aftershocks distribution, along with the Green function for a layered crustal model and stress drop smoothing constraint, to derive a refined coseismic slip model for the Yushu earthquake and to investigate the static stress changes in the surrounding crust affected by the mainshock
It is clear that the distributed slip model can explain most patterns of both descending and ascending observations with a small root mean square (RMS) misfit: 1.8 cm for 487A, and 2.5 cm for 139D interferogram, and those numbers are similar to the level of atmospheric noise in the InSAR coseismic displacements
Summary
We combine Phase Array Lband Synthetic Aperture Radar (PALSAR) InSAR data collected by the Advanced Land Observation Satellite (ALOS) with both ascending strip mode and descending wide-swath mode, geological field observations, and aftershocks distribution, along with the Green function for a layered crustal model and stress drop smoothing constraint, to derive a refined coseismic slip model for the Yushu earthquake and to investigate the static stress changes in the surrounding crust affected by the mainshock. Geological field and InSAR observations indicated that the Yushu earthquake created an ∼70 km long surface rupture zone along the Yushu fault, but there were significant differences in the maximum slip magnitude and spatial slip distribution among these studies. For the past InSAR studies of the 2010 Yushu earthquake, the Green function was only calculated in elastic half-space and the slip smoothing between neighboring fault patches was employed
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have