Rayleigh‐Wave H/V via Noise Cross Correlation in Southern California

Abstract

We study the crustal structure of southern California by inverting horizontal-to-vertical (H/V) amplitudes of Rayleigh waves observed in noise cross-correlation signals. This study constitutes a useful addition to traditional phase-velocity-based tomographic inversions due to the localized sensitivity of H/V measurements to the near surface of the measurement station site. The continuous data of 222 permanent broadband stations of the Southern California Seismic Network (SCSN) were used in production of noise cross-correlation waveforms, resulting in a spatially dense set of measurements for the southern California region in the 1-15 s period band. The fine interstation spacing of the SCSN allows retrieval of high signal-to-noise ratio Rayleigh waves at periods as low as 1 s, significantly improving the vertical resolution of the resulting tomographic image, compared to previous studies with minimum periods of 5-10 s. In addition, horizontal resolution is naturally improved by increased station density. Tectonic subregions including the Los Angeles basin and Salton trough are clearly visible due to their high short-period H/V ratios, whereas the Transverse and Peninsular Ranges exhibit low H/V at all periods.Electronic Supplement: Maps of horizontal-to-vertical (H/V) ratios and their standard deviation, and the count of H/V ratio measurements exceeding the signal-to-noise ratio requirements and tables of the numbers used for the maps, along with figures of inverted V S and a Markov chain Monte Carlo histogram.

Imaging the Eastern Trans‐Mexican Volcanic Belt With Ambient Seismic Noise: Evidence for a Slab Tear

“…The cross‐correlation traces are then rotated from the east‐north‐vertical frame into the radial‐transverse‐vertical frame between all station pairs. To simultaneously determine all nine components of the Green's tensor, we follow Muir and Tsai () and build the rotation matrix as M = M 1 ⊗ M 2 , where M 1,2 are the three‐component rotation matrices from the east‐north‐vertical to the radial‐transverse‐vertical frame for the individual stations, and ⊗ is the Kronecker product. Finally, to enhance the signal‐to‐noise ratio (SNR), the causal and anticausal parts of the cross correlations are stacked to obtain the so‐called symmetric cross correlations.…”

Regional Crustal Imaging by Inversion of Multimode Rayleigh Wave Dispersion Curves Measured From Seismic Noise: Application to the Basque‐Cantabrian Zone (N Spain)

“…This provides a consistent data coverage over a wider range of frequencies (Figure 6). Second, the time‐domain approach suffers the risk of possible misidentification of higher‐mode Rayleigh waves with the fundamental mode (e.g., Muir & Tsai, 2017; Tanimoto & Rivera, 2005), and detailed discrimination between the fundamental mode signal and higher overtones is seldom done. This can lead to important errors when inverting for complex shear‐wave velocity structures (Maraschini et al., 2010).…”

Seismic Noise in Central Alaska and Influences From Rivers, Wind, and Sedimentary Basins

“…A second possible influence of the deep structure is that some of the observed H/Z ratios could be caused by seismic waves, rather than ground tilt. Sedimentary basins, including Nenana basin, distort Rayleigh wave particle motion toward ellipticity having H/Z >1 (Berg et al, 2018;Lin et al, 2012;Muir & Tsai, 2017;Tanimoto et al, 2013;Workman et al, 2017). Large-scale variations in elastic structure will influence the ellipticity of Rayleigh waves as a function of the azimuth of the arriving seismic wave (Maupin, 2017; 10.1029/2019JB017695 Bao & Shen, 2018;Ringler et al, 2019).…”