Liquefaction potential studies of the synclinal area of Indo-Burmese Range, Tripura, India

ABSTRACT Soil liquefaction is a major concern in tectonically dynamic areas, where unscientific urbanization is increasing rapidly. The present study area falls in the Neogene outer wedge of Indo-Burmese Ranges, where subduction related earthquakes dominate, and the synclinal valleys are dominated with younger, unconsolidated, unmatured, loose sediments with varying fines contents and shallow groundwater conditions which are favourable site for liquefaction. Dharmanagar, part of strongly deformed domain of Indo Burma wedge, subjected to frequent earthquake due to ongoing subduction activity of Indian plate beneath Burmese plate. The deterministic liquefaction potential index (LPI) in the Dharmanagar syncline shows significant part of the town falls in very high liquefaction probability zone (33%) and high liquefaction probable zone (38%), which is underlined by recent alluvium and Dupi Tila Formation. The moderate (20%), low (5%), and non-liquefiable (4%) areas of the Dharmanagar occupies mainly the anticlinal, which is dominated with Tipam and Boka Bil Formation. Liquefaction potential in the area shows the requirement of seismic building norms with respect to the rapid urban expansion and the building styles in the Urban and Suburban areas. Also, these younger alluvial areas are vulnerable to even smaller magnitude earthquake (M ≥5), signifies the importance of LPI in the subduction tectonic areas for disaster management and urban development.