Work

Fluid‐Controlled Tidal Modulation of Aftershocks Following the 2022 M6.8 Luding Earthquake

Year: 2026

Type: article

Abstract: Aftershock sequences record how fault zones recover and weaken after earthquakes, but the roles of fluid migration and stress heterogeneity remain difficult to isolate. Earth tides impose predictable stress perturbations and thus provide a natural probe of faults near failure, although their signals are often obscured by aftershock clustering. Here we apply bootstrap‐based spatial spectral analysis to the 2022 M6.8 Luding earthquake sequence to resolve tidal sensitivity. We identify a systematic shift from a fluid‐rich region before the mainshock to the margins of the high‐slip zone, bypassing the rupture core. This pattern suggests coupled interaction between coseismic stress heterogeneity and postseismic fluid redistribution. Elevated pore pressure enhances sensitivity to weak tidal stress in high stress‐gradient regions, whereas permeability contrasts promote localized fluid accumulation and triggering. Our results show that tidal forcing can reveal where postseismic faults are closest to failure, offering an indirect window into fluid migration and fault‐zone weakening.

Source: Geophysical Research Letters

DOI: 10.1029/2026gl125440

Authors: Jinbo Zheng, Wei Wang, Aitaro Kato, Jinhai Zhang

Institutions: Chinese Academy of Sciences, Institute of Geology and Geophysics, University of Chinese Academy of Sciences, Earthquake Research Institute, University of Tokyo, The University of Tokyo

Language: English

Topic: earthquake and tectonic studies

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,190

Funders: Ministry of Education, Culture, Sports, Science and Technology, National Natural Science Foundation of China, China Scholarship Council