Abstract
We estimate time-independent earthquake likelihoods in central Los Angeles using a model of interseismic strain accumulation and the 1932–2017 seismic catalog. We assume that on the long-term average, earthquakes and aseismic deformation collectively release seismic moment at a rate balancing interseismic loading, mainshocks obey the Gutenberg-Richter law (a log linear magnitude-frequency distribution [MFD]) up to a maximum magnitude and a Poisson process, and aftershock sequences obey the Gutenberg-Richter and “Båth” laws. We model a comprehensive suite of these long-term systems, assess how likely each system would be to have produced the MFD of the instrumental catalog, and use these likelihoods to probabilistically estimate the long-term MFD. We estimate Mmax = 6.8 + 1.05/−0.4 (every ~300 years) or Mmax = 7.05 + 0.95/−0.4 assuming a truncated or tapered Gutenberg-Richter MFD, respectively. Our results imply that, for example, the (median) likelihood of one or more Mw ≥ 6.5 mainshocks is 0.2% in 1 year, 2% in 10 years, and 18–21% in 100 years.
| Original language | English |
|---|---|
| Pages (from-to) | 3153-3162 |
| Number of pages | 10 |
| Journal | Geophysical Research Letters |
| Volume | 46 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published (in print/issue) - 28 Mar 2019 |
Funding
C. Rollins was supported by a NASA Earth and Space Science Fellowship for most of this work. The authors are grateful to Tom Parsons and an anonymous reviewer for suggestions that greatly improved the manuscript, as well as numerous colleagues around the community for helpful input and guidance. The authors declare no competing financial interests. The GPS data used to constrain the moment deficit buildup rate in Rollins et al. (2018) and plotted in Figure 1 can be found in Argus et al. (2005, Table 3); the SCEDC seismic catalog is available at http://service.scedc.caltech.edu/ftp/ catalogs/SCEC_DC/.