SCEC Award Number 19120 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Development and Implementation of Full 3-Dimensional Waveform Tomography
Investigator(s)
Name Organization
Thomas Jordan University of Southern California
Other Participants Alan Juarez
SCEC Priorities 3a, 4a, 4c SCEC Groups Seismology, CXM, GM
Report Due Date 04/30/2020 Date Report Submitted 05/10/2021
Project Abstract
 In proposal 19120, we proposed developing and implementing the remaining software toolkits for automating Full 3-Dimensional Waveform Tomography (F3DT) on high-performance computers using the Hercules Toolchain. The proposal was a continuation of a previous SCEC founded project (Award 18121) on the same topic. The F3DT toolkit consists of subroutines for automated source inversion, data extraction, and the iterative tomography algorithm. We report our progress on developing the algorithms and our research towards understanding the effects of shallow seismic velocities on long-period wavefields and their implication for F3DT. The second section of the report focuses on the characterization of seismic source complexity using moment tensor fields, and in section three, we summarize our current efforts towards characterizing stress fields.
Intellectual Merit Our work contributes in a novel way to techniques for determining Earth structure and source structure.
Broader Impacts Our source characterization work shows promise as a method for monitoring changes in stress and the inelastic response to stress in seismically active zones.
Exemplary Figure Figure 1. Average estimations of relative velocity perturbations and amplitude reduction times from the ten pairs of simulations. The top row is the average velocity perturbations measured at (a) 5s, (b) 10 s, and (c) 20 s. The bottom row is the average amplitude anomalies at (d) 5 s, (e) 10 s, and (f) 20 s. The thick red line is the border of the LA basin, where the velocity was reduced by 30%. The focal mechanism indicates the earthquake location and source mechanisms.