Time-Dependent Renewal-Model Probabilities When Date of Last Earthquake is Unknown

Edward H. Field, & Thomas H. Jordan

Published February 2015, SCEC Contribution #1991

We derive time-dependent, renewal-model earthquake probabilities forthe case, in which the date of last event is completely unknown, and compare these with the time-independent Poisson probabilities that are customarily used as an approximation in this situation. For typical parameter values, the renewal-model probabilities exceed Poisson results by more than 10% when the forecast duration exceeds ∼20% of the mean recurrence interval. We also derive probabilities for the case in which the last event is further constrained to have occurred before historical record keeping began (the historic open interval), which can only serve to increase earthquake probabilities for typically applied renewal models.We conclude that accounting for the historic open interval can improve long-term earthquake rupture forecasts for California and elsewhere.

Citation
Field, E. H., & Jordan, T. H. (2015). Time-Dependent Renewal-Model Probabilities When Date of Last Earthquake is Unknown. Bulletin of the Seismological Society of America, 105(1), 459-463. doi: 10.1785/0120140096.

Related Projects & Working Groups
Working Group on California Earthquake Probabilities