Qualitative Liquefaction Potential Mapping for Dhaka Metropolitan Development Plan (DMDP) Area, Bangladesh

Liquefaction potential mapping serves as an important tool, providing valuable guidance for policymakers and directing research and development efforts within urban settings. This study undertakes a qualitative assessment of liquefaction potential in the Dhaka metropolitan development Plan area, utilizing both the liquefaction potential index (LPI) and the Ishihara inspired liquefaction potential index (LPI_ISH). The analysis draws upon a comprehensive dataset consisting of 400 cone penetration tests (CPT) conducted across the entire area. Site-specific peak ground acceleration (PGA) values, categorized into eight distinct zones, are incorporated into the assessment, employing an earthquake magnitude of 7.5 for liquefaction potential computations. Findings from the LPI-based map indicate that approximately 38% of the area exhibits susceptibility to high levels of surficial liquefaction. Conversely, the LPI_ISH map suggests a lower susceptibility, with only 13% of the area. However, it is important to note the inability to calibrate LPI values due to the absence of historical liquefaction data for the region. Furthermore, uncertainties regarding liquefaction susceptibility may arise from factors such as seasonal fluctuations in the groundwater table and variations in geological formations across sites.