Crustal stresses and damage evolve throughout the seismic cycle of the Ridgecrest fault zone

• 成果类型: Article
• 署名作者: Bryan, Jared; Frank, William B.; Audet, Pascal
• 署名单位: Massachusetts Institute of Technology (MIT); University of Ottawa
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8076
• DOI: 10.1126/science.adu9116
• 发表日期: 2025-09-18
• 页码: 1256-1260
• 关键词: san-andreas fault; velocity changes; earthquake sequence; ambient noise; parkfield; california; anisotropy; deformation; fractures; EVOLUTION

摘要

Earthquakes abruptly release tectonic stress that builds slowly over time through the coupled evolution of faults and the surrounding crust. Seismic wavespeeds track crustal deformation and stress changes, but typical monitoring methods are most sensitive to shallow depths. Using receiver functions, we tracked rupture-zone wavespeed and anisotropy changes throughout the crust during the 2019 Ridgecrest earthquake sequence. Shallow coseismic wavespeed reductions recovered within months, whereas a deeper postseismic wavespeed drop persisted without measurable recovery over several years. The deep, persistent wavespeed drop likely reflects accumulating damage driven by postseismic deformation, suggesting two possible scenarios: (i) a slow interseismic recovery where wavespeed and anisotropy track long-term stress evolution; or (ii) permanent deformation of an immature fault zone. Both scenarios affect the dynamics and energy budget of the seismic cycle.