Surface wave tomography from microseisms in Southern California

TLDR

Ambient seismic noise can be used to extract Green’s functions, enabling imaging of Earth structure. The study aims to image surface‑wave velocity structure in Southern California using ambient noise. Using 148 broadband stations, the authors extracted surface‑wave arrival times between all station pairs and applied a densely sampled tomographic inversion to estimate 0.1–0.2 Hz surface‑wave velocities. The resulting velocity model agrees well with prior estimates and confirms that coherent ambient noise can be employed for seismic imaging.

Abstract

Since it has already been demonstrated that point‐to‐point seismic propagation Green Functions can be extracted from seismic noise, it should be possible to image Earth structure using the ambient noise field. Seismic noise data from 148 broadband seismic stations in Southern California were used to extract the surface wave arrival‐times between all station pairs in the network. The seismic data were then used in a simple, but densely sampled tomographic procedure to estimate the surface wave velocity structure within the frequency range of 0.1–0.2 Hz for a region in Southern California. The result compares favorably with previous estimates obtained using more conventional and elaborate inversion procedures. This demonstrates that coherent noise field between station pairs can be used for seismic imaging purposes.