SCEC Award Number 17104 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Global Earthquake Activity Rate Model
Investigator(s)
Name Organization
Yan Kagan University of California, Los Angeles David Jackson University of California, Los Angeles
Other Participants 3
SCEC Priorities 5a, 5c, 5d SCEC Groups CSEP, WGCEP, Seismology
Report Due Date 06/15/2018 Date Report Submitted 11/07/2019
Project Abstract
 The objects of the long-term Global Earthquake Activity Rate (GEAR) project are to construct and test a forecast model (rate of earthquake epicenters within location, magnitude, and time windows) at high resolution (0.1 by 0.1 degree), over the whole earth surface, for events of magnitude 5.8 and larger. Earthquake rates are inferred from a weighted combination of smoothed seismicity and tectonic deformation estimated from plate tectonic and geodetic data. The forecast rate is submitted once, for testing prospectively over an indefinite time interval (decades) against earthquakes reported in the Global Central Moment Tensor (GCMT) earthquake catalog. Magnitudes are assumed to follows the Tapered Gutenberg-Righter distribution with one of five corner magnitude values depending on regional tectonics. The first version (GEAR1) was published in 2015 and submitted to the Collaboratory for Study of Earthquake Predictability (CSEP) for testing. Our subsequent aims have been to
• provide alternate models for shorter term and longer term forecasts,
• reduce the minimum earthquake threshold to magnitude 5 or less,
• use the PDE catalog for better location estimates,
• forecast earthquake focal mechanisms as well as locations,
• explore magnitude and other assumptions using our own versions of CSEP tests.
Intellectual Merit Our project explores the extent to which prior earthquake forecasts, based on common assumptions, agree with earthquake occurrence before and after the forecasts, contributing to the understanding of earthquake processes. We also developed methods for associating finite ruptures on faults with prescribed descriptions of such events, a necessary step in evaluation forecasts of such events, and we tested some of these ideas on forecasts of the Working Group on California Earthquake Probabilities (WGCEP). Association and testing of finite ruptures have been major goals of the Collaboratory for Study of Earthquake Predictability (CSEP).
Broader Impacts Our research affects seismic hazard and risk estimation, with implications for public safety, risk management, and public policy. We’ve presented our results to students and faculty at universities, including UCLA, UC Riverside, ETH Zurich, EFZ Potsdam, Victoria Univerity Wellington, and at SCEC Annual meetings, showing how Physics, Geology, Geodesy, and Statistics can be combined to solve real world problems. We’ve discussed our analysis with students and faculty in Statistics, showing them applications and encouraging their participation in seismological research.
Exemplary Figure Figure 1: Global earthquake long-term focal mechanism forecast based on smoothed seismicity, latitude range (90_ S–90_ N). Focal mechanisms are shown on 5 deg. by 5 deg_ grid.
credit: Kagan, Y.Y., [2017]. Worldwide Earthquake Forecasts, Stoch Environ Res Risk Assess, 31:1273–1290, DOI 10.1007/s00477-016-1268-9.