An updated and unified earthquake catalog of Bangladesh for seismic hazard assessment

Abstract

A comprehensive earthquake catalog is an important input for reliable seismic hazard assessment. In the present study, an updated and unified earthquake catalog has been compiled for Bangladesh covering 150N–320N and 830E–980E. A large number of earthquake event data has been collected from various sources including ISC–GEM Catalog, USGS catalog, ISC Bulletin, etc. Collected data have then been compiled and fake or duplicate events have been eliminated. Earthquake magnitudes that were not reported in moment magnitude (Mw) have been converted to Mw using conversion relations compatible with regional earthquake events. The compiled earthquake catalog consists of 8,024 earthquake events with magnitudes 3.56≤Mw≤8.8 for the period of 825 to 2021. Declustering of the catalog has been performed to remove the foreshocks and aftershocks which results in 7,219 earthquakes in the final catalog. A completeness analysis has been performed for the final catalog. This study proposes Gutenberg-Richter’s earthquake magnitude-frequency relationships for the whole region as well as for five selected regions based on the existing faults within the country. This study provides a database with a solid background for future works in the field of seismicity, seismic hazard assessment, and ground response studies for the country.