SCEC Award Number 18178 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Towards Structural Imaging using Ambient Field Correlation Artifacts
Investigator(s)
Name Organization
Gregory Beroza Stanford University Lise Retailleau Stanford University
Other Participants
SCEC Priorities 4a, 4c, 4d SCEC Groups Seismology, CME, GM
Report Due Date 03/15/2019 Date Report Submitted 05/08/2019
Project Abstract
 We map scatterers linked to the heterogeneous structure of California using spurious arrivals in the correlations computed from the data recorded from 2001 to present. We extract spurious (acausal) arrivals in correlation functions from sets of reference stations versus groups of stations. We demonstrate the method in areas of strong suspected heterogeneity, in particular the edges of basins. Basins are of particular interest because they are implicated in ground motion amplification, and their boundaries are difficult to constrain with conventional seismic imaging. We find that the method successfully images the location of the Sierra Nevada - Great Valley boundary.
Intellectual Merit This approach has been used to image localized scatterers at the global scale. We have extended it to the regional scale and used it to image the lateral boundary of the Great Valley. Imaging vertical/dipping structure is challenging, and this method offers a promising new approach.
Broader Impacts Better images of structures, particularly basin boundaries, are essential to improving the accuracy of physics-based ground motion simulations.
Exemplary Figure Figure 1. Figure 4: Steps of the process using correlation "artifacts" to locate the scatterers. a) Correlation functions between the westernmost station (green in d) and the eastern stations (black in d). b)