Repeating Earthquakes Trigger Themselves in Parkfield

Justin L. Rubinstein, & William L. Ellsworth

Submitted August 11, 2017, SCEC Contribution #7500, 2017 SCEC Annual Meeting Poster #001

Previous studies of repeating earthquake sequences in Parkfield, Taiwan and Japan yield that repeating earthquakes behavior is better predicted by a characteristic earthquake model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models. This implies that the elastic rebound model that underlies the time- and slip-predictable models offers no predictive information in an event-to-event sense. While we find no predictive power in the time- and slip-predictable models, we find a scaling between slip and the preceding recurrence time for some repeating earthquake sequences in Parkfield, whereby the magnitude increases with increasing inter-event time. We believe this scaling arises from an elastic behavior where the loading rate or coupling coefficient on a slip-patch instantaneously increases at the time of rupture and decays back to a constant rate over time. This would mean that the seismic slip budget would always be increasing, but it would accumulate more rapidly immediately following slip on the asperity. This behavior would produce the slip-predictable sense scaling that we observe. Additionally, the moment rate of the repeating earthquake sequences that we study is consistent with observations of afterslip in the same area, which decays in a power-law sense.

Citation
Rubinstein, J. L., & Ellsworth, W. L. (2017, 08). Repeating Earthquakes Trigger Themselves in Parkfield. Poster Presentation at 2017 SCEC Annual Meeting.


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