SCEC Award Number 18055 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title An analysis of spatio-temporal variations of seismicity and strain in the Salton Trough
Name Organization
Jean-Philippe Avouac California Institute of Technology
Other Participants Zachary Ross, Postdoctoral Scholar
TBA, Grad Student
SCEC Priorities 5c, 1e, 5e SCEC Groups SDOT, SAFS, FARM
Report Due Date 03/15/2019 Date Report Submitted 03/15/2019
Project Abstract
We analyze the spatiotemporal variations in seismicity and strain in the Salton Trough. We used a template matching catalog spanning ten years. We examined both individual earthquake clusters and long-term variations in seismicity rate. Long term strain rates show a seasonal pattern. However, we have not detected a seasonal pattern with the seismicity. Seismicity streaks are clearly evidenced on portion of Imperial fault but don’t follow the same temporal statistics as similar streaks seen on the creeping portion of the San Andreas fault. Interevent time distribution of the background seismicity is apparently not Poissonian due to long period of quiescence not predicted by the model.
Intellectual Merit This research is contributing to advancing the understanding of fault processes and earthquakes at a fundamental level and to potentially improving methods for seismic hazard assessment. A fundamental finding, which needs further investigation, is that the seismicity analyzed as part of this project does not seem to follow the classical Poisson process assumed in seismic hazard studies.
Broader Impacts The project provided support for a summer undergraduate research intern (Joe Duncan-Duggal)
Exemplary Figure Relocated seismicity from in the Imperial fault region (black dots). Red dots indicate the locations of template events that detected more than 50 earthquakes over the 10 year period. Interevent time distributions don’t follow the prediction of the Poisson model, even after removal of aftershocks sequence.