Seismic Imaging of Southern California with Scattered Waves

Jorge A. Castellanos, Robert W. Clayton, & Voon Hui Lai

Published August 7, 2019, SCEC Contribution #9365, 2019 SCEC Annual Meeting Poster #053

The generation of a high-resolution velocity model of southern California has been the center of attention for many years. The recent growth of high-density seismic arrays has led to the development of velocity models that can now explain most of the first-order features observed in recordings of local and regional earthquakes. However, the majority of these models are generated using conventional geophysical imaging techniques such as surface-wave tomography and seismic refraction surveys. These methods, in spite of their well-proven accuracy, provide only an approximation of the crust’s true structure as they tend to be a smooth version of the real velocity distribution. For this reason, sharp velocity discontinuities, such as faults and basin edges, are often poorly resolved and generally not included in most seismic models. Here, we explore the feasibility of using scattered waves to image sharp structural boundaries in southern California by back-projecting the P-wave coda energy of over 1,000 local earthquakes recorded by the SCSN network. Our preliminary migrated images show a large concentration of scattered energy being generated across the transverse mountain ranges and around Los Angeles basin. This technique promises to be an efficient and direct way of deterministically characterize the effect of sharp structural heterogeneities in producing the high-frequency component of ground motion.

Key Words
Scattering, Seimic Imaging

Castellanos, J. A., Clayton, R. W., & Lai, V. (2019, 08). Seismic Imaging of Southern California with Scattered Waves. Poster Presentation at 2019 SCEC Annual Meeting.

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