Major-Earthquake Recurrence Patterns on Active Faults in Yunnan Province, China

ABSTRACT Earthquake forecasting along active faults is important for reducing future seismic losses, especially in active zones such as Yunnan Province. However, the major earthquake recurrence patterns of faults in Yunnan remain understudied, and the time-dependent probabilities are still unclear. Here, we collected paleoseismic data on 20 fault segments in Yunnan, fit these data using four types of renewal processes, and calculated the probability of at least one major earthquake occurring on each segment over the next 30 yr. Approximately half of the fault segments show evidence of quasi-periodic recurrence, as indicated by the 95% credible intervals of their shape parameters being inconsistent with the random recurrence boundary. The Weibull renewal process is more likely to best reproduce recurrence times, followed by the lognormal renewal process. Five (≥4%) fault segments have relatively high earthquake occurrence probabilities. We also estimated the distribution of next-event times and found that fault segments with higher earthquake probabilities generally tend to have earlier expected times for the next earthquake. In this study, we conducted long-timescale recurrence analysis under restrictive assumptions, without taking into account multisegment rupture, stress interaction, and magnitude-specific modeling. Therefore, further research is required in these aspects in follow-up research.