Green’s functions retrieved by Multi-Component C3 for Ground Motion Prediction

Yixiao Sheng, Gregory C. Beroza, & Marine A. Denolle

Submitted August 12, 2016, SCEC Contribution #6673, 2016 SCEC Annual Meeting Poster #274

We follow the Virtual Earthquake Approach, proposed by Denolle et al (2013), to predict strong ground motion, based on the surface response determined from the ambient seismic field. Instead of just using cross-correlation (C1), we use C3, cross-correlation of the coda of the cross-correlation, to estimate the impulse responses. It has been shown that C3 can mitigate the uneven excitation of the ambient seismic wavefield, and result in more symmetric Green’s functions (Stehly et al, 2008 and Froment et al, 2011). In addition to using vertical-vertical component in C1, we utilize other components, such as vertical-east and vertical-north to construct C3 from multiple components. To keep retain amplitude information, we follow Denolle et al (2013), using deconvolution interferometry to calculate C1. C3 amplitudes are then calibrated with the C1 amplitudes. We test this approach on the 2016 Mw 5.2 Borrego Springs earthquake, using station YN.TR02, 2.5 km away from the epicenter, as a virtual source. We show that the Green’s function estimated by multi-component C3, though noisier, are comparable to and more symmetric than those estimated by C1. We observe large energy on R-T, T-R, Z-T and T-Z components of the Green’s function tensors, indicating for strong Love-Rayleigh conversions. Such wave conversions can have a strong effect on the ground motion prediction results.

Key Words
Green’s functions, Multi-Component C3, Ground Motion Prediction

Sheng, Y., Beroza, G. C., & Denolle, M. A. (2016, 08). Green’s functions retrieved by Multi-Component C3 for Ground Motion Prediction. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Ground Motion Prediction (GMP)