SCEC Award Number 11039 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Detecting Strain Transients in Southern California
Name Organization
Jeffrey McGuire Woods Hole Oceanographic Institution
Other Participants Matt Wei, WHOI Postdoc
SCEC Priorities A5 SCEC Groups Geodesy, Seismology
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
We propose to continue the implementation of an algorithm for analyzing the datasets produced by dense continuous geodetic networks to detect deformation transients. Copious amounts of continuous GPS data are being collected in Southern California and other regions, but there is not yet a well accepted algorithm for routine processing of this data to systematically identify times when transient deformation occurred. We have detected several potential transients in the Salton Trough, but all are small (few mm) and need to be verified with InSAR data to determine if they are of tectonic origin, a focus of this proposal’s effort.
Intellectual Merit Deformation transients are ubiquitous in continuous geodetic datasets from other tectonic regions but relatively few have been well observed in Southern California and those were primarily relatively well understood post-seismic responses to large earthquakes. Over the last several years our group has combined InSAR and GPS studies to detect geodeticaly observed deformation transients in Southern California, particularly in the Salton Trough and begin understanding the physical mechanisms that make such events more prevalent in the Salton Trough than elsewhere in Southern California.
Broader Impacts The funds were used primarily to support a post-doctoral researcher.
Exemplary Figure Figure 1. Map gives the horizontal components of the transient deformation field between the time of the March 9 foreshock and the March 11 mainshock from Miyazaki, McGuire, and Segall [2011] as well as the foreshock and mainshock epicenters (stars). Panels on the right show the east component GPS time series (blue dots, scale is in meters) for the 4 stations denoted by the red triangles on the map. The red line shows the estimated sum of all of the contributions to the GPS time series including a step at the time of the foreshock and the contribution from transient aseismic deformation (black curve) that accounts for ~1 cm of displacement between foreshock and mainshock.