EVALUATING THE MEGATHRUST EARTHQUAKE PREDICTIONS FOR ASSESING SEISMIC RISKS IN BANGLADESH

Bangladesh, situated in a region of significant tectonic activity, frequently experiences low to moderate magnitude earthquakes, raising substantial concerns regarding earthquake hazards among residents. A comprehensive understanding of seismic risk factors is essential for effective risk management.

Geologically, Bangladesh encompasses much of the Bengal Basin and the Indo-Myanmar Ranges (IMR), characterized by a complex setting involving multiple tectonic plate boundaries and the dispersion of tectonic stress. A few recent studies utilizing modeling techniques have indicated the potential for high-magnitude earthquakes (magnitude 8-9) within the Bengal Basin. To better comprehend these predictions, detailed geological investigations into the geometry of subduction zones and tectonic stress data from the IMR were conducted, along with an analysis of the seismic history along the IMR and the Andaman-Nicobar Island arc.

This study undertook a comprehensive assessment of the hypothesized hidden megathrust within the central Bengal Basin, which has been proposed as a significant seismic threat with the potential to generate catastrophic earthquakes in the region. To investigate this hypothesis, an extensive analysis of geological and geophysical data was conducted. This included the examination of seismic reflection profiles, stratigraphic records, and tectonic stress fields. However, the results of this detailed investigation did not substantiate the existence of such a megathrust. The absence of supporting evidence from the geological and geophysical data suggests that the predictions of catastrophic earthquakes originating from a hidden megathrust in the Bengal Basin may be exaggerated.