| Autor: |
He, Lijia, Feng, Guangcai, Wu, Xiongxiao, Lu, Hao, Xu, Wenbin, Wang, Yuedong, Liu, Jihong, Hu, Jun, Li, Zhiwei |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters; 12/28/2021, Vol. 48 Issue 24, p1-10, 10p |
| Abstrakt: |
The May 22nd, 2021, Mw ${\mathrm{M}}_{\mathrm{w}}$ 7.4 Maduo earthquake occurred on an intraplate fault of Bayan‐Har block in the Tibet Plateau. Here, we derive the coseismic and early postseismic surface deformations from the Sentinel‐1 (S1) interferometric synthetic aperture radar (InSAR) data. We use the subpixel offsets of SAR and Sentinel‐2 (S2) optical images to determine the surface rupture traces. The fault geometry and coseismic fault slip distribution of multi‐segmented ruptures are estimated by inverting InSAR interferograms and SAR pixel offsets. We show that at least five fault segments with curved geometry are activated, with a peak coseismic slip of about 5 m. The geodetic data inversion suggests that an NW‐striking blind segment near the Eling Lake may have ruptured during the 2021 event. Postseismic slip inversion with the 60‐day cumulative line‐of‐sight deformations, shows that the early afterslip of 0.1 ∼ 0.3 m occurred mostly toward the downdip direction of the main coseismic slip asperities. The afterslip geodetic moment accounts for approximately 15.3% of the coseismic one. Coulomb stress analysis shows that the nucleation of the Maduo earthquake is partially facilitated by the 1947 M7.7 Dari earthquake. Plain Language Summary: We derive the co‐ and postseismic deformations and fault‐slip distributions of the 2021 Maduo earthquake from the space‐based geodetic data. We find that the pattern of eastward and upward postseismic deformations is similar to that of the coseismic left‐lateral motions, and the 60‐day early afterslip of 0.1∼0.3 m occurrs mostly toward the down‐dip of the main coseismic slip asperities. We propose a six‐segment geological structure model with varied dips and orientations to better recover the actual surface deformations. We find that at least five fault segments are activated from west to east. We examine the stress loading induced by the 1947 M7.7 Dari and the 2021 Maduo earthquakes. We find that nucleation of the 2021 event is partially facilitated by the 1947 event, and the 2021 event increases the potential seismic risk on the Tuosuo Lake and Maqin segments of the East Kunlun fault. Key Points: Co‐ and post‐seismic deformations and fault‐slip distributions of the 2021 Maduo earthquake are derived from space‐based geodetic dataA six‐segment geological structure model with varied dips and orientations is proposed for interpretation of the Maduo eventThe 1947 Dari earthquake increases stress in the western rupture zones and partially promotes the fault failure of the Maduo event [ABSTRACT FROM AUTHOR] |
| Databáze: |
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