Localization and coalescence of seismicity before large earthquakes in California

Ilya Zaliapin

Submitted July 30, 2020, SCEC Contribution #10227, 2020 SCEC Annual Meeting Talk on TBD

This talk discusses an ongoing project focused on localization of deformation around faults that are generally locked in the interseismic periods before the occurrence of large earthquakes. It has been long known from laboratory fracture experiments and model simulations that large failure events in heterogeneous materials are preceded by a long phase of distributed deformation, followed by a progressive localization that culminates with macroscopic instabilities. We develop improved tools for tracking space-time evolution of earthquakes and apply them to high-quality seismic catalogs to detect localization patterns. Analysis of seismicity in southern and Baja California documents earthquake-induced rock damage along with localization and coalescence of seismicity prior to the large earthquakes in the area (1992 Landers, 1999 Hector Mine, 2010 El Mayor-Cucapah, 2019 Ridgecrest). Corresponding analysis around the 2004 M6 Parkfield earthquake in the creeping section of the San Andreas fault shows contrasting tendencies to those associated with the large seismogenic faults. Continuing studies with these techniques, combined with analysis of geodetic data and insights from laboratory experiments and model simulations, might improve the ability to track preparation processes leading to large earthquakes.

Key Words
localization, coalescence

Zaliapin, I. (2020, 07). Localization and coalescence of seismicity before large earthquakes in California. Oral Presentation at 2020 SCEC Annual Meeting.

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