Assessing seismic soil liquefaction susceptibility and hazard zonation in Bihar, India: a comparative study of deterministic methods

Bihar is a heavily populated state in India. It is experiencing a rapid increase in construction activities due to industrial expansion. The state is known for its high seismic activity, having experienced several earthquakes in the past, including the devastating 1934 earthquake and the most recent in 2015. The alluvial deposits in the Indo-Gangetic plain of Bihar caused substantial seismic soil liquefaction. Overpopulation and poor construction techniques have caused extensive damage to property and life. This study aims to provide an assessment of the seismic soil liquefaction susceptibility of Bihar with varying earthquake magnitudes (Mw) of 6.0, 6.5, 7.0, and 7.5. In the present study, two deterministic methods given by Tokimatsu and Yoshimi (1983) and IS 1893 (Part 1): (2016) have been used, and their results have been compared. Also, the study intends to produce a hazard zonation map of Bihar. The study shows that the liquefaction susceptibility of soil is significantly influenced by the depth of soil below ground level, Mw, standard penetration test (SPT) N-value, and fines content (FC). The hazard zonation maps reveal a high vulnerability of northern districts like Sitamarhi, Madhubani, and Supaul at Mw = 6.0. At Mw = 7.5, almost the entire state is prone to soil liquefaction. This emphasizes the importance of investigation and highlights the need for careful engineering practices to mitigate liquefaction hazards in Bihar.