Research Projects

The study focuses on the statistics of powerful earthquakes, which have long-term economic and societal importance. Earthquakes are a complex threshold process with non-trivial space-time correlations, but can be considered as renewal point processes. Statistical methods are developed to examine inter-arrival time distribution, space-time clustering of seismic events, and hierarchical interplay between point processes. The study focuses on the physical relevance of powerful earthquakes (M≥6) and derives statistics of inter-arrival times between successive large earthquakes for long-term earthquake forecasting and statistics of small inter-event counts between successive large events for contemporary earthquake nowcasting. Earthquake forecasting is a conventional approach, while earthquake nowcasting is a modern method of estimating seismic risk by evaluating the progress of the earthquake cycle in a fault system. The study area is the seismically active Himalaya and its adjoining regions. Using a set of probability distributions, statistical inference, uncertainty estimation, and empirical results, the study reveals exciting physical properties of the changing state of the Himalayan earthquake system in terms of regional crustal structure, stress accumulation, and stress release. The research combines present-state (nowcasting) with future-state (forecasting) of a fault system, providing spatial distribution of earthquake hazards in the Himalayan region and potentially improving disaster mitigation, social policymaking, and other end-user applications in the region.