Present day interseismic slip rates of the Xianshuihe Fault observed by InSAR

Yuexin Li, & Roland Bürgmann

Published August 13, 2018, SCEC Contribution #8412, 2018 SCEC Annual Meeting Poster #121

Located at the southeastern boundary of the Tibetan Plateau, the Xianshuihe Fault is one of the most active major faults in China. It serves as one of the main structures accommodating the collision between the Indian and Eurasia plates. Historically, more than 20 M>6 earthquakes ruptured the fault since 1700. With the recent launch of ESA Sentinal-1 and JAXA ALOS-2, large spatial coverage and short recurrence intervals make the study of spatial and temporal features of fault slip rates with InSAR possible.

In our study, we use more than 3 years of Sentinel-1A data to obtain the interseismic surface velocity field along the Xianshuihe Fault. The Small Baseline Subset method (SBAS, Berardino et al., 2002) is used to process time series from more than 170 interferograms. The turbulent component of atmospheric delay is corrected iteratively using a common point stacking method (Tymofyeyeva and Fialko, 2015). Then tropospheric delay is further mitigated by fitting a linear trend between line of sight deformation and the topography. Remaining unwrapping errors are excluded by throwing away data points with large residuals.

To complement the InSAR results, GPS velocities from Zheng et al. (2017) are also used for slip rate inversions and forward modeling. We aim to extract a full 3D deformation field with the combination of Sentinal-1, ALOS-2 and GPS data. The GPS velocities will help document InSAR satellites’ capability of capturing subtle long-wavelength interseismic signals in a limited time span. With the InSAR results, we also seek to resolve slip rates, locking depth, and partially coupled or creeping sections on the Xianshuihe Fault, which will help us better evaluate the earthquake potential in this area.

Key Words
InSAR, fault creep, slip rates

Citation
Li, Y., & Bürgmann, R. (2018, 08). Present day interseismic slip rates of the Xianshuihe Fault observed by InSAR. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy