1. Fault‐Tolerant b‐Values and Aftershock Productivity.
- Author
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Page, M. T. and Elst, N. J.
- Subjects
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EARTHQUAKE aftershocks , *EARTHQUAKES , *EARTHQUAKE hazard analysis , *INDUCED seismicity - Abstract
When it comes to smaller earthquakes, are major faults special? Page et al., (2011,https://doi.org/10.1029/2010JB007933) showed that earthquakes near the faults that compose version 3.0 of the Southern California Earthquake Center 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 overtuned 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 also "fault‐tolerant"—that is, insensitive to distance from major faults. 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. Plain Language Summary: Individual geologic faults are not isolated. They work together to accommodate the motion between tectonic plates. In this study, we looked at earthquakes that are very close to well‐mapped faults such as the San Andreas, as well as earthquakes that occurred far from these faults. We found that earthquakes could be just as large and just as likely to trigger another large earthquake, regardless of whether they were on a major fault or a minor one. Thus, all faults are important; all faults can potentially host a large earthquake, particularly if they "link up" with faults around them. Key Points: The Gutenberg‐Richter b‐value does not change with distance from the major mapped faults in Southern CaliforniaAftershock productivity is also insensitive to distance from major faultsThese results suggest that the faults in Southern California form a highly connected fault network [ABSTRACT FROM AUTHOR]
- Published
- 2018
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