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Faulty Intuition about b-values and Aftershock Productivity within a Fault Network

Morgan T. Page, & Nicholas J. van der Elst

Published August 15, 2018, SCEC Contribution #8671, 2018 SCEC Annual Meeting Poster #044

When it comes to smaller earthquakes, are major faults special? Page et al. (2011) showed that earthquakes near the faults that compose version 3.0 of the SCEC Community Fault Model (CFM) have a lower Gutenberg-Richter b-value than earthquakes elsewhere in Southern California. Here we revisit their result, using newer earthquake data recorded after version 3.0 of the CFM was completed. We find that the correlation between earthquake size and proximity to major faults is not present in the newer seismicity data. This indicates that to some degree the CFM is over-tuned to past seismicity, with some structures related to transient features in seismicity rather than persistent geologic features. We also search for differences in aftershock productivity and foreshock statistics near faults, and find that they are insensitive to distance from major faults as well. Our results suggest that the fault system in Southern California is highly connected, since the chance of an earthquake nucleating on or near a major fault versus on a secondary structure is independent of its final size.

Key Words
b-values, aftershocks, CFM, seismicity, connectivity, fault network

Page, M. T., & van der Elst, N. J. (2018, 08). Faulty Intuition about b-values and Aftershock Productivity within a Fault Network. Poster Presentation at 2018 SCEC Annual Meeting.

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