Ambient noise attenuation tomography of Love & Rayleigh waves applied to the Ramona reservation linear array across the San Jacinto Fault Zone

Xin Liu, Gregory C. Beroza, & Yehuda Ben-Zion

Published August 14, 2020, SCEC Contribution #10632, 2020 SCEC Annual Meeting Poster #040 (PDF)

We study the near-surface fault zone structure from ambient seismic noise data. The amplitude of the seismic wavefield contains information on seismic attenuation, which is sensitive to fault damage zone characterized by well-developed fractures within the fault zone, and possibly fluids. We extract amplitude decay information with uncertainty from the noise interferometry functions of seismic data recorded by a dense linear array of 65 3-C sensors across the San Jacinto Fault Zone at the Ramona reservation north of Anza, California. Then we invert for attenuation structure based on the linear station-triplet method (Liu et al. 2015; Allmark et al. 2018) for both Love and Rayleigh waves. The attenuation tomography results show strong attenuation (low Q values) correlated with known San Jacinto Fault surface traces and damage zone structure. The results also suggest radial anisotropy of shear attenuation, which is possibly due to the distinct sensitivity of SH and SV modes to different fracture orientations.

Key Words
attenuation tomography, ambient noise, fault damage zone, San Jacinto fault

Citation
Liu, X., Beroza, G. C., & Ben-Zion, Y. (2020, 08). Ambient noise attenuation tomography of Love & Rayleigh waves applied to the Ramona reservation linear array across the San Jacinto Fault Zone. Poster Presentation at 2020 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology