Abstract
On September 16, 2015, a magnitude 8.3 earthquake struck west of Illapel, Chile. We analyzed Sentinel-1A/IW InSAR data on the descending track acquired before and after the Chile Mw8.3 earthquake of 16 September 2015. We found that the coseismic deformation field of this event consists of many semi circular fringes protruding to east in an approximately 300km long and 190km wide region. The maximum coseismic displacement is about 1.33m in LOS direction corresponding to subsidence or westward shift of the ground. We inverted the coseismic fault slip based on a small-dip single plane fault model in a homogeneous elastic half space. The inverted coseismic slip mainly concentrates at shallow depth above the hypocenter with a symmetry shape. The rupture length along strike is about 340 km with maximum slip of about 8.16m near the trench. The estimated moment is 3.126×1021 N.m (Mw8.27)，the maximum depth of coseismic slip near zero appears to 50km. We also analyzed the postseismic deformation fields using four interferograms with different time intervals. The results show that postseismic deformation occurred in a narrow area of approximately 65km wide with maximum slip 11cm, and its predominant motion changes from uplift to subsidence with time. that is to say, at first, the postseismic deformation direction is opposite to that of coseismic deformation, then it tends to be consistent with coseismic deformation.It maybe indicates the differences and changes in the velocity between the Nazca oceanic plate and the South American continental plate.
Highlights
On September 16, 2015, a magnitude of Mw8.3 earthquake struck off shore of Chile and induced tsunami
We investigate the coseismic and postseismic deformation fields produced by the 2015 Mw8.3 Chile earthquake using InSAR data from Sentinel-1A/IW on descending orbit
It consists of dense concentric semi-circular fringes convex to east, the dominant motion direction is subsidence of LOS(moving away from the satellite), meaning the South American plate westward movement
Summary
On September 16, 2015, a magnitude of Mw8.3 earthquake struck off shore of Chile and induced tsunami (http://earthquake.usgs.gov/). This huge event occurred on the subduction zone between the Nazca and South America plates in Central Chile, with the epicenter about 85 km distant to the Chile trench(Figure 1). We use Sentinal-1A/IW InSAR data to map the coseismic deformation field the Mw8.3event and invert the spatial variations of fault slip. We use four SAR images acquired at different times after the mainshock to reveal the pattern and variation of the short-term post-seismic. The black rectangle is the fault plane projected onto the surface
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
