Interseismic Deformation and Fault Kinematics along the Keping Foreland Thrust-Fold Belt of the South Tian Shan from InSAR and GPS Observations
Session: Modern Geodesy for Observation and Its Modeling of Earthquake Deformation [Poster]
Type: Poster
Date: 4/19/2021
Presentation Time: 03:45 PM Pacific
Description:
Although previous large-scale interseismic GPS measurements have documented a shortening rate of ~6-8 mm/yr between the southwest Tian Shan and the northwest Tarim Basin, the question associated with how the shortening is accommodated by a suite of thrust and detachment fault and their interactions along the Keping foreland thrust-fold belt (hereinafter the Keping fault) are still poorly understood. It is largely due to complex fault interactions and their geometries plus limited geodetic observations in this region. Spatially dense geodetic observations may help to better resolve complex fault kinematics in a greater detail and thus leas to an update of seismic hazard assessment. In this study, we obtained line-of-sight (LOS) interseismic velocity fields around the Keping fault using small baseline subset (SBAS) analysis of C-band Sentinel-1 SAR data during 2015-2020 (ascending track T129 and descending T34). The LOS interseismic velocity indicates that obvious interseismic deformation occurred on the Keping fault, with an maximum LOS velocity of ~2.8mm/yr. By combining with GPS measurements, decomposition of descending and ascending InSAR observations demonstrates the spatial pattern of tectonic uplift on the Keping fault with a rate of ~1-3 mm/yr. Compared with the N-S shortening rate of ~6-8 mm/yr inferred from GPS data, we argue that the vertical movement of the Keping fault is relatively moderate at present. The clear contrast between N-S shortening rate and uplift rate highlight the fact that the convergence between the southwest Tian Shan and the Tarim Basin is mainly aborted by the napped fold deformation in the form of the upward motion along the Keping fault.
Presenting Author: Chenlong Li
Student Presenter: Yes
Authors
Chenlong Li Presenting Author chenglong-li@ies.ac.cn China Earthquake Administration |
Guohong Zhang Corresponding Author zhanggh@ies.ac.cn China Earthquake Administration |
Xinjian Shan xjshan@ies.ac.cn China Earthquake Administration |
Dezheng Zhao dezhengzhao@ies.ac.cn China Earthquake Administration |
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Interseismic Deformation and Fault Kinematics along the Keping Foreland Thrust-Fold Belt of the South Tian Shan from InSAR and GPS Observations
Category
Modern Geodesy for Observation and and Its Modeling of Earthquake Deformation