Liquefaction hazard mapping in DMDP area of Bangladesh: A comprehensive assessment using SCPT data and multiple severity indices

Abstract

Only a small number of studies in the past have used a substantial amount of data to assess the liquefaction risk in Dhaka, the capital of Bangladesh. Dhaka falls within a moderate seismic zone. Due to the extensive number of development projects in this area, it has become crucial to identify high-risk regions with good precision. This study is an attempt to develop a liquefaction potential map for the Dhaka Metropolitan Development Plan (DMDP), having an area of 1530 sq. km based on an ample number of SCPT data using BI-14 triggering methodology and three severity indices (LPI, LPI_ISH, LSN). Micro-zoned PGA value of a 475-year return period, combining soil type and deposit, has been used to analyze a 400 SCPT dataset by Horizon software, recently developed by Geyin and Maurer. This study has produced four maps based on the LPI, LPI_ISH, LSN indices and a combination of LPI and LPI_ISH to evaluate the seismic risk intensity across the DMDP area. Depending on cumulative frequency curves, a zonation-based analysis has been developed using two dominant soil deposits to enhance the applicability of the result. For Zone 1 (Floodplain Deposit), 79 %, 68 %, 63 % and 77 % of the area have been marked as susceptible to liquefaction by LPI, LPI_ISH, LSN and combined index respectively. In Zone 2 (Madhupur Clay Deposit), assessments indicated that 65 %, 36 %, 38 % and 55 % of the area are prone to liquefaction susceptibility. This study has anticipated to provide policymakers with valuable insights regarding urban planning, development, expansion, implementation of safety measures, and production of risk management plans.