Liquefaction hazard assessment in a seismically active region of Himalayas using geotechnical and geophysical investigations: a case study of the Jammu Region

Abstract

The Jammu Region (JR) in the northwestern Himalayas trigged by medium to high magnitude near-field as well as far-field earthquake events, including the most recent 2019 Mirpur earthquake. In this paper, an attempt has been made to develop the zonation map for liquefaction hazard in the JR based on liquefaction potential index (LPI) and probability of liquefaction (PL). To achieve this, factor of safety against liquefaction was estimated using standard penetration test (SPT) data collected from geotechnical consultancies and shear wave velocity measured during field testing at 243 locations, and an integrated liquefaction hazard map generated. The liquefaction features such as sand blows and ground rupture were found in Jatah (Samba district) and Simbal (Jammu district). According to the integrated hazard map, places near the bank of Tawi River and Ravi River in Jammu have young alluvium, making them particularly prone to liquefaction. Liquefaction does not occur in the eastern and western sections because of high shear wave velocities and rock at shallow depth, and it also does not occur in the central area due to thick sand deposits. LPI values ranged from 0 to 27.45 having very low to very high liquefaction risk. PL is greater than 0.75 for sites located on the southwestern side due to uniformly graded soil having extremely low SPT (N) and Vs values. This study will aid site planners in the construction of structures that consider liquefaction mitigation and well-defined liquefaction risk measures.