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Ambient Noise Love Wave Attenuation Inversion using the LASSIE Array through Los Angeles Basin

Xin Liu, & Gregory C. Beroza

Published August 15, 2019, SCEC Contribution #9810, 2019 SCEC Annual Meeting Poster #056

We present a simple and efficient method to extract the attenuation quality factors using the ambient seismic noise data from the LASSIE linear array located at the southeastern edge of the Los Angeles basin. The three-component LASSIE array spans ~40 km and crosses several regional faults (e.g. Newport-Inglewood fault and Los Alamitos fault). We only extract the Love wave amplitude information using seismic noise interferometry because the Rayleigh wave components contain mixed fundamental and first higher modes while the Love wave component is dominated by fundamental mode. We apply the method based on the amplitude ratios from a linear triplet of stations (Liu et al., 2015; Allmark et al., 2018). To minimize the effect of noise sources, we take the amplitude ratios for two pairs of stations with similar Fresnel zone widths (Liu and Beroza 2019). We apply this technique to all qualifying station triplets and invert for the attenuation Q values at different periods using damped linear least-square method. Then we convert the Q tomography results at different periods to shear wave attenuation at different depths. The results suggest good correspondence between strong attenuation and fault zones for the shallow structure in the top 600 m.

Key Words
seismic interferometry, attenuation, Los Angeles basin

Liu, X., & Beroza, G. C. (2019, 08). Ambient Noise Love Wave Attenuation Inversion using the LASSIE Array through Los Angeles Basin. Poster Presentation at 2019 SCEC Annual Meeting.

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