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

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 along the dense line of sensors. The presence of low frequency peaks ( 0.2 Hz) in the HVSR and their modeling 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 in extremely good agreement with the SCEC community velocity model in most of the basin area. 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.