Tracking seismic velocity perturbations at Ridgecrest using ballistic correlation functions

Yixiao Sheng, Aurélien Mordret, Florent Brenguier, Lisa Tomasetto, Quentin Higueret, Coralie Aubert, Dan Hollis, Frank Vernon, Yehuda Ben‐Zion

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

Resumé

We present results based on data of a dense nodal array composed of 147 stations, deployed in 2022 near the epicenter of the 2019 M7.1 Ridgecrest earthquake to investigate characteristics of the seismic wavefields. Through array analyses, we identified two primary components. First, we observed far‐field P waves dominating the 0.5–1.2 Hz frequency range, which are likely primarily generated by wind‐driven oceanic swell activity. Second, we detected near‐field body waves resulting from anthropogenic activities in the frequency range 2–8 Hz. We examined noise correlation functions derived from data of the dense deployment and regional stations to explore fault‐zone seismic velocity changes using ballistic arrivals, with a focus on velocity perturbation shortly before and after the Ridgecrest earthquake sequence. Our findings exhibit distinct behavior compared to results obtained through standard coda‐wave interferometry. Particularly, we observed a decrease in P‐wave travel time on certain station pairs prior to the 2019 earthquake sequence. Supported by detailed investigation of the local seismic wavefields, we interpret the decreasing P‐wave travel time as likely caused by a velocity increase away from the fault, possibly related to fluid migration. However, additional information is necessary to verify this hypothesis.
OriginalsprogEngelsk
Sider (fra-til)2452-2463
Antal sider12
TidsskriftSeismological Research Letters
Vol/bind95
Udgave nummer4
DOI
StatusUdgivet - jul. 2024
Udgivet eksterntJa

Programområde

  • Programområde 3: Energiressourcer

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