Seismic Hazard Analysis for the South-Central Coastal Region of Bangladesh Considering the Worst-Case Scenario

• Published in: Pure and applied geophysics 2021-08, Vol.178 (8), p.2821-2838
• Main Authors: Kamal, A. S. M. Maksud, Mitu, Momtahina, Hossain, Md. Shakhawat, Rahman, M. Moklesur, Rahman, Md. Zillur
• Format: Article
• Language: English
• Subjects: Acceleration; Bedrock; Coastal zone; Distance; Earth and Environmental Science; Earth Sciences; Earthquake magnitude; Earthquakes; Geological hazards; Geophysics/Geodesy; Ground motion; Hazard assessment; Seismic activity; Seismic hazard
• ISSN: 0033-4553; 1420-9136
• DOI: 10.1007/s00024-021-02770-7

There is a long history of catastrophic earthquakes in and around Bangladesh due to the ongoing collision of the Indian and Eurasian plates. In this study, deterministic seismic hazard analysis (DSHA) is carried out for the south-central coastal region of Bangladesh. As a case study, important locations (i.e., Kumirmara, Nilganj, Dhulasar, Moudubi, and Char Muntaz) are selected to identify the areas that will experience the maximum and minimum seismic hazards if a catastrophic earthquake occurs. The peak ground acceleration (PGA) and spectral acceleration (SA) values at bedrock and ground surface conditions are estimated considering the worst-case scenario by using all possible seismogenic sources, controlling earthquakes, and two sets of ground motion prediction equations (GMPEs). The GMPEs and seismotectonic maps are used to determine the controlling earthquakes and the shortest distances from the sources to study areas. It is predicted that the Chittagong-Tripura folded belt (CTFB) source, which is located at the shortest distance from the selected areas, may produce the maximum magnitude earthquake. As the ground motion intensities depend on the earthquake magnitude and the distance from the sources, the maximum ground motion (PGA and SA) is observed for the CTFB source. The estimated maximum and minimum PGA values are 0.535 g and 0.301 g at the reference bedrock conditions in Char Muntaz and Kumirmara, respectively. It is observed that at all conditions and for all sources, Char Muntaz will experience the greatest ground motion and Kumirmara will experience the least ground motion. The result of this study will help to select the areas for the development of critical infrastructure in the coastal region of Bangladesh.