Statistical monitoring and early forecasting of earthquake sequence: Case studies after the 2019 M6.4 Searles Valley Earthquake, California

Yosihiko Ogata, & Takahiro Omi

Published August 12, 2020, SCEC Contribution #10448, 2020 SCEC Annual Meeting Poster #098 (PDF)

This presentation considers the possible implementation of operational short-term forecasting and analysis using a real-time hypocenter catalog of ongoing seismic activity anywhere worldwide. by reviewing case-studies of the aftershocks of M6.4 Searles Valley earthquake before the M7.1 Ridgecrest earthquake. (1) First, the short-term ETAS prediction of spatio-temporal activity was carried out in real time. The hierarchical space-time ETAS model leads to both anisotropic real-time forecast of space-time aftershock activity and the background seismic activity in a wide region for obtaining the secular probabilities of large earthquakes. (2) Second, we need to evaluate whether or not a first strong earthquake may be a foreshock of a further large earthquake. (3) Third, short-term probability forecast of early aftershocks are much desired despite bad conditions for data acquisition, even for evaluating a larger earthquake than the first main shock. (4) Finally, de-trending the temporal activity of the entire aftershocks by stretching and shrinking according to the rate of the Omori-Utsu formula or ETAS model, we observe the spatio-temporal distribution where the patterns may be abnormal, such as relative quiescence, relative activation, or migrating activity.
-- Such anomalies should be recorded and listed for the future evaluation of the probability of a possible precursor before a large aftershock or a nearby new rupture.

Key Words
Ridgecrest earthquake sequence, real-time forecasting and diagnoses, hierarchical space-time ETAS models, background seismicity rates, foreshock probabilities, early aftershock forecasts

Citation
Ogata, Y., & Omi, T. (2020, 08). Statistical monitoring and early forecasting of earthquake sequence: Case studies after the 2019 M6.4 Searles Valley Earthquake, California. Poster Presentation at 2020 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Forecasting and Predictability (EFP)