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Top1. Introduction
Earthquake is the most challenging catastrophic disaster in the world periodically occurred due to the movement of tectonic plates beneath the earth which causes dynamic vibration on the surface of the earth. Earthquakes can make enormous damages to the structures like buildings, roads, and industrial structures, and its disruption in the disaster relief and renewal the damages, which cause massive losses in the economy of the country. Many scientists worked on earthquakes and identified the liquefaction in the soil due to earthquakes. The technical name of liquefaction was introduced by Mogami and Kubo in the year of 1953 (Mogami and Kubo, 1953). Liquefaction occurs in saturated soil as well as sandy soil and clayey soil which has high porous soil particles. Basically, soil is a mixer of soil solids particle which has a bonding with each other due to gravity. Seismic wave produces dynamic vibration between the soil solids particle during the earthquake and changes soil stresses between solid particles. It decreases the effective stress in the soil particle and increases the pore water pressure which makes soil solids into a liquid state and resulting in loss of strength in soil solids. The state of solids to the liquid state of soil is liquefaction. Most of the damages occurred due to liquefaction classified as 3 important hazardous. The first one is classified as landslides which causes failure of dam embankment and ground lateral spreads. Surface manifestation is the second major hazard of liquefaction; therefore, it develops sand blows and ground movement like cracks. The third utmost effect settlement of foundation in building and tilting of the building is the consequence hazards of liquefaction. Therefore, liquefaction is the most important and complex problem in earthquake geotechnical engineering.
Many researchers proposed various methods to estimate liquefaction susceptibility or cyclic softening potential (Seed, 1982; Seed et al., 1983; Seed and Idriss, 1967; Skempton, 1986). Carrying undisturbed samples in the field with adequate quality and cost involved is very difficult therefore, Seed and Idriss (1971) explored and developed stress-based simplified technologies to assess the probabilistic liquefaction. They used this procedure for standard penetration test (SPT) and cone penetration test (CPT). The simplified procedure includes evaluation of cyclic stress ratio (CSR), cyclic resistance ratio (CRR), and factor of safety (FOS) at a given depth, to assess liquefaction potential due to seismic performance case history and consistent in-situ tests of SPT. These simplified procedures were all developed by (Cetin et al., 2004; Seed and Idriss, 1971).