Time-dependent probabilistic seismic hazard assessment in Kerman and adjacent areas in the west of Lut block, Central-East Iran

Abstract

This study is the first attempt to apply fault-based and time-dependent seismicity models cooperatively for probabilistic seismic hazard assessment (PSHA) of the Kerman and adjacent areas (54–59° E, 28.5–34° N). For this study, almost all available literature and databases have been investigated to compile reliable information reported as instrumental, historical, and paleoseismological events, together with the geometry and kinematics information for active faults. This information systematically is integrated and contributed to PSHA. Conditional probabilities of occurrence for earthquakes greater than the maximum earthquake from which its standard deviation is deducted (M > Mmax − σMmax) are computed based on a Brownian passage time (BPT) model. The spatial distribution of the time-dependent peak ground acceleration (PGA) has been calculated, and spectral accelerations have been computed for three selected cities (Kerman, Rafsanjan, Ravar), with 10% probability of exceedance in 50 years. The time-dependent PSHA map for PGA shows variations from − 21 along the Gowk fault to + 32% near the Sabzevaran fault segments in comparison with the corresponding time-independent PGAs. The difference between the time-dependent and time-independent PGAs at most parts of the study area is negligible, especially at sites farther away from the faults, where the differences vary from − 7 to + 7%. Moreover, the difference between the time-dependent and time-independent spectral accelerations for Ravar and Rafsanjan cities is insignificant. However, this difference at periods of 0.1–0.3 s is significant in Kerman city. The results of this study provide a stimulus for considering time-dependency assumption and fault-based approach in future earthquake-resistant constructions required in Kerman and adjacent areas.