Abstract:
The ability to determine the current state of seismic cycle of large sized earthquakes is of profound importance in societal policymaking and disaster preparation. In this article, we present a probabilistic formulation of event-based natural time counts to develop earthquake potential score (EPS) at 36 cities from northeast India, Bangladesh, and adjoining areas. The time-dependent natural time analysis provides an attractive regional seismic hazard evaluation method, because it (1) exhibits spatiotemporal and clustering invariability, ensuring model consistency, (2) considers "seismic cycles" for a network of faults in a defined area, and (3) enables some physical interpretations aligned with earthquake generation process characterized by stress accumulation and moment release. The modeling results for M ≥ 6 events reveal that EPS values lie between 41 and 94%, with the scores of Agartala (91%), Aizawl (84%), Dimapur (80%), Guwahati (41%), Imphal (90%), Malda (70%), Shillong (52%), Siliguri (73%), Barisal (59%), Chittagong (94%), Comilla (88%), Dhaka (78%), Mymensingh (81%), Narayanganj (77%), Rangpur (55%), and Sylhet (60%). These values essentially serve as a yardstick to statistically assess the current state of regional seismic cycle progression in the study region, bringing out some key information to the decision-makers, engineers, scientists, and citizens to improve earthquake preparedness and mitigation strategies.