LIQUEFACTION SUSCEPTIBILITY MAPPING IN THE EVANSVILLE, IN
Since there are high uncertainties involved in the calculation of liquefaction susceptibility because of the spatial variability of the soil column, a probabilistic method is adapted for the second phase. The deterministic method tells us simply whether or not there would be liquefaction if the soil profile is known exactly at a given site. However, the probabilistic method will gives us the probability of the occurrence of liquefaction based on the statistics of the material properties, so we can determine which general regions are susceptible to liquefaction.
The resulting maps quantify the high liquefaction potential in the river alluvium where the soil profile contains more sand, and describe the contrasting region of lacustrine deposits that predominantly include clayey soil with lower liquefaction susceptibility.
The soil profile within the deposits of the terrace alluvium region is more complex as it contains highly variable sequences of silty sand, clayey sand, and sandy clay. There is no consistency of the liquefaction potential index even though the soil profiles belong to same surficial geologic unit, but there is some indication of a weak correlation with depositional history. Therefore, the probabilistic method is more appropriate for liquefaction susceptibility mapping of the high variation soil profiles in this region. This procedure is used to provide a comprehensive map for liquefaction hazard in and around Evansville.