Earthquake-Induced Landslide Hazard Assessment in Chittagong Metropolitan Area.

This study aims to assess earthquake-induced landslide hazard in Chittagong Metropolitan Area (CMA). The region is at high risk of landslides that have caused loss of lives and properties in the past. Due to the tectonic settings, the earthquake ground motion can act as an active contributing factor to landslides in the Tertiary soft sedimentary rocks of the hilly terrains of Bangladesh. That’s why the contribution of ground motion in causing landslides needs to be considered. Therefore, this research investigated the landslide-prone areas caused by earthquakes in the hilly areas of Chittagong Metropolitan Area (CMA) along with other contributing parameters. In this study, topographical parameters are prepared using the DEM data. The physical and engineering properties of the soils have been determined from the laboratory testing of the soil samples collected during field investigation. This study used the peak ground acceleration (PGA) value for 2% and 10% probability of exceedance (PoE) in 50 years. The pseudo-static model is used to derive the landslide hazard scenarios in the CMA by employing two distinct approaches, i. e., direct estimation and Monte-Carlo (MC) simulation. ArcMap 10.8 has been used for the direct estimation approach, while Python scripting has been used for the Monte-Carlo simulation. This work evaluates the landslide-prone areas of CMA produced by the earthquake ground motion and other triggering parameters by comparing the results from Monte-Carlo simulation and the direct estimation approaches. The research identified 37% and 35% of the hilly terrain of the CMA as landslide-prone regions for 2% and 10% PoE of PGA in the MC simulation approach, and again 28% and 26% landslide-prone regions for 2% and 10% PoE of PGA respectively in the direct estimation approach. The results of this analysis will guide engineers and designers in selecting safe locations for buildings and other infrastructures that will protect people's lives and properties from the devastating consequences of landslides.