SCEC Award Number 12110 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Transient Detection using SCIGN and PBO data with contributions to the CGM.
Investigator(s)
Name Organization
Thomas Herring Massachusetts Institute of Technology
Other Participants Kang Hyeun Ji, Mike Floyd (post-doctoral fellows)
SCEC Priorities 5b, 1d, 1c SCEC Groups Transient Detection, Geodesy, SDOT
Report Due Date 03/15/2013 Date Report Submitted N/A
Project Abstract
 The primary tasks of our current SCEC research are to develop near real-time transient detection algorithms and to generate a consensus Western United States velocity field as a contribution to the community geodetic model. We applied our TPO method to Long Valley and the results have been published in Ji et al., 2013. The method tracked an inflationary event in the caldera that started in late 2011. We have not seen a significant increase in seismicity rate associated with the recent inflation event in the LVC region (Fig. S4). The Epidemic-Type Aftershock Sequence (ETAS) model [Ogata, 1988], a stochastic seismicity rate model, is able to fit the seismicity since 2007 with constant background rate and triggering parameters. An update on the TPO results from the Ji et al., 2013 paper shows that the recent inflation event has stopped and the caldera appears to have started contracting. We have been investing post seismic deformation following the major earthquakes in Southern California. We looking at the long-range postseismic deformations modeled in Freed et al., 2010 and extending that analysis to 13 years after the Hector Mine event (compared to 7 yrs in the original publication). We are also seeing evidence of similar large-scale postseismic deformation after the El Mayor Cucapah earthquake in 2010.
Intellectual Merit Our main contributions to SCEC have been in making available results from our combination of SCIGN and PBO GPS data, crustal motion models and tectonic velocity fields for Southern California and the Western United States for use in the unified California earthquake rupture forecast models, and how development and discussions of transient signal detection.
Broader Impacts Our publications on the nature of post-seismic deformation and the processes that generate these signals, transient signal detection on the Akutan volcano, inflationary events in the Long Valley Caldera and in the San Gabriel Valley have demonstrated to the scientific community the potential applications of the methodologies and data being developed at SCEC.
Exemplary Figure Figure 4: (a) Map of the Long Valley Caldera region. The spatial pattern from a principal component analysis (black vectors) and the velocity estimates with data after 2011.75 (blue vectors) represent a radial deformation pattern from the resurgent dome. The sites with white squares are not used in the analysis. Scales are shown above the inset map. The PCA amplitude is a fraction of the amplitude of the TPO time series shown in (b). The error ellipses of the observed velocities indicate 95% confidence interval. (b) TPO time series (dots) and 1-sigma uncertainties (gray error bars). The black and blue two-sided arrows indicate, respectively, the intervals in which the PCA pattern was calculated and the observed velocity field was calculated. Note the significant inflation that started in the late 2011. (c) Values of chi-square per degrees of freedom (χ_dof^2; gray). The black lines are 30-day averages. χ_dof^2 has increased since 2011, suggesting increasing misfits in projection.