Incorporating fault maturity-related earthquake slip characteristics into final rupture length determination for Earthquake Early Warning
Abstract
There is a current debate about how far into an earthquake's duration its final size can be determined. Meier et al., [2017] normalize source time functions with respect to time and find that generally, the final size of an earthquake cannot be estimated until it is halfway over. Melger and Hayes, [2019], however, combine GNSS displacements and moment acceleration to find that larger earthquakes are distinguishable 10 seconds after the P-wave arrival. Here, we introduce a new method for final earthquake size determination based on a relationship between along-strike fault maturity, slip distribution, and final rupture length. Based on a collection of 26 Mw 6.5 + unilateral continental earthquakes, Perrin et al., [2017] have indeed shown that the generic asymmetry of earthquake slip profiles results from the rupture producing the largest slip in the more mature part of the ruptured fault, while the slip decays quasi-linearly in the direction of fault immaturity. Therefore, using 1) the generic slip profile (averaged from Perrin et al.'s data), 2) an empirically derived backprojection algorithm for slip based on peak ground displacements and station distance from the fault [Aagard et. Al., 2004], and 3) the line-Source estimates of FinDer [Böse et al., 2012, 2015, 2017], we created a hybrid cross-correlation misfit algorithm that works in both the static and dynamic domains; at every step of the rupture growth, the algorithm searches for the best fit between the generic slip profile template and the measured slip, which in turn gives the final rupture length. We tested the algorithm in the static domain on 26+ earthquakes slip profiles and in the dynamic domain on several recent earthquakes including the 2016 Mw 7.0 Kumamoto and the 2008 Mw 7.9 Wenchuan events. Results show that our algorithm well predicts the final rupture length and magnitude of the earthquake more rapidly than through 50% of the duration of the event. Therefore, the new algorithm can be a useful module in Earthquake Early Warning and will be a procedure associated with FinDer called FinDerS: FinDer-Slip.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S52B..02H
- Keywords:
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- 4341 Early warning systems;
- NATURAL HAZARDS;
- 7212 Earthquake ground motions and engineering seismology;
- SEISMOLOGY;
- 7215 Earthquake source observations;
- SEISMOLOGY