SCEC Award Number 18126 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Systematic Studies of Dynamic Triggering at Volcanic and Geothermal Sites
Investigator(s)
Name Organization
John Vidale University of Southern California Xiaofeng Meng University of Southern California
Other Participants
SCEC Priorities 1e, 3f, 5e SCEC Groups Seismology, MSW, FARM
Report Due Date 12/15/2019 Date Report Submitted 01/07/2020
Project Abstract
 For dynamic triggering studies, there has been continuous development over the years on how to identify positive triggering cases. We systematically study dynamic triggering at well-instrumented volcanic and geothermal sites along the west coast of United States. We select four geothermal fields in California (i.e., The Geysers, Coso, Long Valley and the Salton Sea) and five Cascade volcanoes (i.e., Mount Rainier, Mount St. Helens, Mount Hood, Lassen Peak and Mount Shasta), because of the dense instrumentation and ample background earthquakes. We identify 45 potential dynamic triggering cases at four Cascade volcanoes and four geothermal fields in California. We do not see any correlation between the significance of seismicity rate increase and peak dynamic stresses. Moreover, we find that in many cases, the significant rate increases are caused by earthquake swarms, which may not be caused by large mainshocks. Using a variety of time windows could improve the reliability of the statistical analysis. The underlying physics of dynamic triggering is still elusive, mostly due to our limited knowledge on how to identify positive triggering cases.
Intellectual Merit The work explored the quantity and timing of seismicity triggered by moderate and strong shaking in and near volcanoes and geothermal areas, which is a question ripe for further investigation in the quest to decipher the factors that affect the timing of earthquakes.
Broader Impacts We increased the resolution of the amount of triggering, which is not so large. Earthquake forecasting near volcanoes and seismically active geothermal regions is a significant concern to society, and so while we did not publicize results, this activity directly addresses societal concerns.
Exemplary Figure Figure 3 in report. The evolution of seismicity for all potential triggering cases for Cascade volcanoes (left) and geothermal fields in California (right). Red and black dots denote template and detected events, respectively. Blue lines denote the cumulative number of earthquakes.