Earthquake Analysis of The Hindukush Range by Using Statistical Methods

Abstract

The Hindukush region is renowned for its high seismic activity, making it a crucial area for earthquake analysis. This research examines the earthquake data from 2008 to 2010 utilizing sophisticated statistical techniques. The earthquake catalog contains both dependent and inde pendent events, required declustering to eliminate dependent events. The study focuses declus tering methods with the Gardner-Knopoff approach to identify mainshocks. The declustering found 3164 clusters of earthquakes with a total of 3574 (37.5 %) events out of 9532 with only the mainshock shown on a color-coded seismicity map. The Gutenberg-Richter relationship was used to assess the distribution of magnitudes, indicating a completeness magnitude of Mc = 3.03. Temporal and spatial analyses revealed a high productivity rate “a” of 5.21, indicating significant seismic activity, and “b” value of 0.98, reflecting notable higher frequency of smaller earthquakes. Variations in b-values were linked to the region’s distribution of earthquake mag nitudes, while the high “a” value was due to elevated seismic activity. Moreover, the research employed the ETAS model to distinguish between background and triggered seismic activity in a defined area, identifying 146 target events and classifying 75% as background events. Us ing an iterative stochastic declustering method, the ETAS model yielded Maximum Likelihood estimates for important parameters, emphasizing the connection between mainshocks and af tershocks. The plot of estimates of ETAS model and spatial and temporal plots were utilized providing valuable information for assessing seismic hazard and evaluate the model’s accuracy. This research provides crucial insights on earthquake risks in the Hindukush area, enhancing earthquake assessment and risk analysis.