Communications Earth & Environment (Mar 2025)

The 11-month precursory fault activation of the 2019 M L 5.6 earthquake in the Weiyuan shale gas field, China

  • Jinping Zi,
  • Yuyun Yang,
  • Hongfeng Yang,
  • Jinrong Su

DOI
https://doi.org/10.1038/s43247-025-02151-1
Journal volume & issue
Vol. 6, no. 1
pp. 1 – 15

Abstract

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Abstract Anthropogenic activities such as hydraulic fracturing (HF) can trigger destructive earthquakes, the triggering mechanisms of which are still in debate. We utilize near-fault seismic recordings to study the preparatory phase of the 2019 M L 5.6 earthquake in the Weiyuan shale gas field (WSGF), Sichuan Basin, China, which struck 3 months after stimulation completion. This is one of the largest HF-triggered earthquakes worldwide. We observed an 11-month-long precursory fault activation, during which continuous seismicity illuminated the fault plane and provided warnings for a potential destructive earthquake. The fault activation is a consequence of injections in multiple HF well pads, with a variety of mechanisms at play. Numerical simulation reveals that the occurrence of the mainshock involves stress perturbation from post-injection aseismic slip. This work promotes our understanding of HF-induced earthquakes and suggests incorporating long-term near-fault observations and taking post-injection aseismic slip into account for effective hazard management.