Dependence of b-value on depth, co-seismic slip, and time for large magnitude earthquakes

John M. Aiken, Takahiko Uchide, & Danijel Schorlemmer

Submitted August 15, 2016, SCEC Contribution #6944, 2016 SCEC Annual Meeting Poster #312

Spatial and temporal variations in parameters of earthquake sources and seismicity will be a key to understand the status of faults such as applied stress and fault strength and hence the potential of earthquake occurrence. Recent studies have shown that the b-value of the Gutenberg-Richter relationship decreases before large magnitude events for timescales of five years or more. In addition, large co-seismic slip values have been found to occur in extremely low b-value regions, e.g., the 2011 Tohoku-oki earthquake [Nanjo, et. al. 2012]. A comprehensive understanding requires us to explore the relationship between depth, co-seismic slip of a large earthquake, time, and b-value for large magnitude events occurring in different tectonic environments (oceanic and in-land). Here we present work studying the relationship between co-seismic slip and b-values prior to two large magnitude events in Japan, the 2016 M7.0 Kumamoto earthquake and the 2011 Tohoku-oki earthquake, using the Japan Meteorological Agency (JMA) earthquake catalog. We calculated the b-values at three-dimensionally distributed grids using the maximum likelihood estimation method and the reported JMA magnitude of completeness. We examined the cross section of depth, co-seismic slip, and time with the calculated b-values to investigate whether a common behavior exists prior to large events. These results will be used in designing a final model submitted to the Collaboratory for the Study of Earthquake Predictability (CSEP), Japan for testing.

Key Words
earthquake statistics, earthquakes

Aiken, J. M., Uchide, T., & Schorlemmer, D. (2016, 08). Dependence of b-value on depth, co-seismic slip, and time for large magnitude earthquakes. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Collaboratory for the Study of Earthquake Predictability (CSEP)