Integrating Time-Dependent and Time-Independent Earthquake Recurrence Models for Fault-Based Seismic Hazard Mapping in Indonesia
Abstract
. Indonesia requires precise seismic hazard assessments to mitigate risks from extreme tectonic plate convergence. Currently, standard mapping heavily relies on time-independent Poisson models, which ignore the elapsed time since historical earthquakes and fail to capture cyclic fault behavior. Updating national hazard maps urgently demands time-dependent approaches. Therefore, this research integrates Poisson and Brownian Passage Time (BPT) models across active faults in Indonesia to dynamically evaluate rupture probabilities and enhance probabilistic seismic hazard assessment (PSHA). Earthquake catalogs (1900–2025) and national fault parameters were processed using OpenQuake. Crucially, the BPT approach estimates rupture probability from tectonic stress accumulation, recurrence intervals, elapsed time, and an aperiodicity parameter (=0.5) characterizing cycle variability. Results demonstrate the BPT model's sensitivity in identifying late-cycle faults, projecting >90% rupture probabilities for the Aceh-South and Batee A segments, while confirming significant hazard reductions (3.75%) for early-cycle faults like Palu-Saluki. To maintain comprehensive coverage, the Poisson model generated a broader baseline hazard distribution, yielding peak ground accelerations (PGA) exceeding 1.35 g at a 2% probability of exceedance in 50 years on Northern Sumatera faults. Integrating these complementary models produces cycle-consistent spatial hazard patterns, providing a robust foundation for national infrastructure planning.