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On the Link Between Glacial Ablation in the Gongga Mountain, Southeastern Tibetan Plateau and the Aftershocks of the 2022 Moxi Earthquake (M6.8)

Description: 

On September 5, 2022, an M6.8 earthquake struck the Moxi segment of the strike-slip Xianshuihe Fault in the southeastern Tibetan Plateau. The aftershocks included a seismic cluster at the foothills of the Gongga Mountain (7,556 m), where the co-seismic Coulomb stress change (△CFS) was negative. We propose that this cluster of aftershocks is linked to pore-pressure diffusion, driven by elevated background pore pressure in the foothills due to significant glacial ablation over recent decades in the Gongga Mountain. To investigate this, we developed a poroelastic finite element model that incorporates the region's initial pore-pressure variations. The model simulated both co-seismic and post-seismic changes in pore pressure and Coulomb stress. Our findings reveal that the co-seismic slip of the mainshock initially caused a drop in Coulomb stress at the foothills of the Gongga Mountain. However, this was followed by a gradual increase in stress due to pore-pressure diffusion. The △CFS eventually became positive, coinciding with the occurrence of a cluster of aftershocks, including two M≥5.0 normal faulting events, at the mountain's foothills. These results suggest that variations in initial pore pressure - strongly influenced by glacial ablation - played a key role in the aftershock sequence of the Moxi earthquake. This highlights the potential impact of global warming-induced glacial ablation on seismic activity, particularly in tectonically active regions.

Session: Mechanistic Insights into Fluid-induced Earthquakes from the Laboratory to the Field - II

Type: Oral

Date: 4/15/2025

Presentation Time: 05:00 PM (local time)

Presenting Author: Mian

Student Presenter: No

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