Back to Search
Start Over
Coseismic Slip Model of the 2022 Mw 6.7 Luding (Tibet) Earthquake: Pre‐ and Post‐Earthquake Interactions With Surrounding Major Faults.
- Source :
- Geophysical Research Letters; 12/28/2022, Vol. 49 Issue 24, p1-10, 10p
- Publication Year :
- 2022
-
Abstract
- The 5 September 2022 Mw 6.7 Luding earthquake occurred on the Moxi segment of the highly active Xianshuihe fault in eastern Tibet. Here, we constrain the coseismic slip by jointly inverting the coseismic displacements measured by Global Positioning System, seismometer and Interferometric Synthetic Aperture Radar. Along the Moxi fault, concentrated left‐lateral strike slip extends ∼30 km along the strike above 10 km depth, producing 0.7–1.0 m shallow slip. Clustered aftershocks and slip inversions suggest that the secondary conjugate Mozigou fault may also involve the rupture. Southward rupture propagation is likely arrested by the barrier‐like fault segments of the Xianshuihe fault, characterized by high interseismic coupling (>0.6) and reduced shear stress rate (<1 kPa/yr) due to interactions with surrounding large locked asperities. The distribution of aftershocks is highly correlated with the positive coseismic Coulomb failure stress changes , which bring the adjacent asperities on the Anninghe and Daliangshan faults ∼0.2 MPa closer to failure. Plain Language Summary: The Mw 6.7 Luding earthquake occurred in eastern Tibet on 5 September 2022, causing 93 casualties and 25 people missing, and substantial damage in the epicentral regions. In this study, we derive the static coseismic displacements from Global Positioning System, seismometer and Interferometric Synthetic Aperture Radar observations. We jointly invert these datasets for the coseismic slip distribution. Our results reveal that the coseismic slip is likely distributed on the conjugate Moxi and Mozigou faults, with the primary slip concentrated on the Moxi fault. We compare the coseismic slip with both the interseismic coupling distribution and shear stress rate on the Moxi fault. We find that the southward coseismic rupture termination is spatially coincident with the areas undergoing a low pre‐earthquake shear stress rate and a high interseismic coupling. The comparison suggests that the coseismic slip during the Luding earthquake is likely controlled by pre‐earthquake interactions with surrounding locked zones on the Anninghe and Daliangshan faults (DLS). We calculate the coseismic Coulomb failure stress changes and demonstrate that the aftershocks could be explained by the induced positive stress perturbations. We conclude that the Luding mainshock enhances earthquake hazards on the Anninghe and DLS. Key Points: Global Positioning System, seismometer, and Interferometric Synthetic Aperture Radar measurements reveal concentrated coseismic slip extending 30 km on the Moxi fault at 0–10 km depthInteractions with large locked asperities lower the shear stress rate to the south of earthquake and lead to the arrest of coseismic ruptureThe Luding event brought the Anninghe and Daliangshan faults ∼0.2 MPa closer to failure, representing enhanced earthquake hazard [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00948276
- Volume :
- 49
- Issue :
- 24
- Database :
- Complementary Index
- Journal :
- Geophysical Research Letters
- Publication Type :
- Academic Journal
- Accession number :
- 161029337
- Full Text :
- https://doi.org/10.1029/2022GL102043