Poster #131, Fault and Rupture Mechanics (FARM)

The role of partial ruptures in the observed moment-recurrence scaling of repeating earthquakes

Alice R. Turner, & Jessica C. Hawthorne
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Poster Presentation

2021 SCEC Annual Meeting, Poster #131, SCEC Contribution #11183 VIEW PDF
Repeating earthquakes are thought to represent the repeated rupture of loaded patches surrounded by regions that are slipping aseismically; they provide a natural laboratory to study interactions between seismic and aseismic processes. These events occur less often than one would expect if these earthquakes accommodate all of the long-term slip. Recent crack models using rate-and-state friction (e.g Cattania and Segall, 2018; Chen and Lapusta, 2009) suggest a possible explanation: for small events, a larger amount of the slip budget on the patch being taken up by aseismic slip. For larger events where most of the slip budget is seismic, the patch experiences partial ruptures, also leading to... the deviation from expected scaling. We aim to test the predictions of this model of repeating ruptures by searching for the proposed partial ruptures. We choose to search using the Northern California earthquakes catalogue, which contains many well-located repeating earthquake sequences. Preliminary results suggest that partial ruptures in the Parkfield region are not common. If preliminary results pass additional tests, it may suggest that partial ruptures do not make up a significant proportion of the slip budget of larger repeating earthquakes in this region.