Postseismic Deformation Following the 2013 Mw 6.6 Lushan Earthquake, China From Continuous GPS Data
Date: 4/25/2019
Time: 06:00 PM
Room: Grand Ballroom
The rheological structure of the crust and upper mantle has an important influence on the mechanical modeling of solid Earth deformation, which includes the deformation models of the Tibetan Plateau, China. As the easternmost boundary of the plateau, the Longmenshan Faults Zone (LFZ) may be different in crustal structure and mechanical properties compared to the region within the plateau. In recent years, with the postseismic deformation following the 2008 MW 7.9 Wenchuan earthquake, many studies have been carried out to better understand the rheological nature of the lithosphere beneath the mid-northern segment of the LFZ [e.g., Huang et al., 2014]. However, many differences exist between the mid-northern and southern segment of LFZ, such as faults activities, magnitude of large earthquakes [e.g., Xu et al., 2009, 2013]. The occurrences of 2013 MW 6.6 Lushan earthquakes give us an opportunity to study the rheological properties of southern segment of LFZ. After the wenchuan earthquake, a temporary continuous GPS network consisting of 7 stations was installed in and around the southern segment of the LTB. This GPS network recorded the postseismic influence of the 2008 Wenchuan earthquake on the southern segment of the LTB and the preseismic, coseismic and postseismic deformations resulting from the 2013 Lushan earthquake. We first extracted the postseismic deformation following the Lushan earthquake with exponential fit model. Then, theoretical value of postseismic deformation is estimated with half space dislocation model. Viscosities of the mid-lower crust and the lower velocity zone are inverted by comparing the observed and theoretical postseismic deformation of the Lushan earthquake. The result shows that rheological properties of different segments are not the main reason that result in differences between the Wenchuan and Lushan earthquake. A greater number of structures may contribute to weaker fault activity in the southern segment, and thus, weaker fault activity produced the difference in magnitude between the Wenchuan and Lushan earthquakes.
Presenting Author: Qixin Wang
Authors
Qixin Wang qixin0321@163.com Institute of Geology, China Earthquake Administration, Beijing, , China (Mainland) Presenting Author
Corresponding Author
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Xiwei Xu xiweixu@vip.sina.com Key Laboratory of Active Tectonics and Volcanos, Institute of Geology, China Earthquake Administration, Beijing, , China (Mainland) |
Zaisen Jiang jiangzaisen@126.com Key Laboratory of Earthquake Prediction, Institute of Earthquake Science, China Earthquake Administration, Beijing, , China (Mainland) |
Postseismic Deformation Following the 2013 Mw 6.6 Lushan Earthquake, China From Continuous GPS Data
Category
Advances in Tectonic Geodesy