Assessing the Deep Geometry of the Los Angeles Basin Using Full H/V Spectral Ratio and Multimode Surface Waves

Zack Spica, Mathieu Perton, Robert W. Clayton, & Gregory C. Beroza

Published August 14, 2018, SCEC Contribution #8566, 2018 SCEC Annual Meeting Poster #146

The H/V spectral ratio (HVSR) of the auto-correlated signal at a seismic station is proportional to the ratio of the imaginary parts of the Green's function. Observations of H/V can be compared to their theoretical counterpart for a locally layered elastic media to constrain the velocity structure. We use broadband stations of the “Los Angeles Syncline Seismic Interferometry Experiment” (LASSIE) to perform a combined inversion of multiple HVSR measurements and multimode dispersion curves for Rayleigh and Love waves along the dense line of sensors. The presence of low frequency peaks (~0.1 Hz) in the HVSR allow us to constrain the deep structure of the basin. Our modeling differs substantially in approach from previous measurements of crustal velocity structure in southern California; however, the velocity models we obtain are for some position in good agreement with the SCEC community velocity model. Our results confirm both the utility of the diffuse field HVSR measurements for deep structural characterization and the predictive value of the SCEC community velocity model in the Los Angeles region.

Citation
Spica, Z., Perton, M., Clayton, R. W., & Beroza, G. C. (2018, 08). Assessing the Deep Geometry of the Los Angeles Basin Using Full H/V Spectral Ratio and Multimode Surface Waves . Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
SCEC Community Models (CXM)