Reflection images from ambient seismic noise

High-resolution surface-wave tomography from ambient seismic noise.

Cross-correlation of 1 month of ambient seismic noise recorded at USArray stations in California yields hundreds of short-period surface-wave group-speed measurements on interstation paths. We used these measurements to construct tomographic images of the principal geological units of California, with low-speed anomalies corresponding to the main sedimentary basins and high-speed anomalies corr...

Extracting time-domain Green’s function estimates from ambient seismic noise

[1] It has been demonstrated experimentally and theoretically that an estimate of the Green’s function between two seismic stations can be obtained from the time-derivative of the long-time average cross correlation of ambient noise between these two stations. This TDGF estimate from just the noise field includes all tensor components of the Green’s function and these Green’s function estimates...

Pitfalls in constraining attenuation from ambient seismic noise

We numerically investigate the ability of ambient noise surface wave interferometry to invert for anelastic attenuation. Shorter correlation time windows leads to higher signal-to-noise ratio of empirical Green’s functions (EGF’s). We show, however, that it is necessary to correct for the window length and that this is especially important if short time windows are employed. Furthermore, we sho...

Surface Wave Tomography of China from Ambient Seismic Noise Correlation

We perform ambient noise tomography of China using the data from the China National Seismic Network and surrounding global and regional stations. For most of the station pairs, we retrieve good Rayleigh waveforms from ambient noise correlations using 18-months of continuous data at all distance ranges across the entire region (over 5000 km) and for periods from 70 s down to about 8 s. We obtain...

Seismic Gradiometry using Ambient Seismic Noise in an Anisotropic Earth