Hazard and risk analysis of soil liquefaction

Natural hazard risk assessment helps decision makers for planning and prioritizing disaster management strategies. This paper focuses on the prediction of different scenarios and assessing the risk of soil liquefaction. The vulnerability of the elements due to soil liquefaction was determined. The Gorgan state (1600 km2), Golestan Province, Iran was considered as a case study for assessing the vulnerability due to this phenomenon. Soil deposits map, ground water depth, and the earthquake acceleration map (based on the occurred historical earthquake points) have been prepared for this study. An empirical liquefaction model as a function of the three studied variables was used to model the liquefaction in four hazard classes using the ArcGIS software. Possible scenarios was determined considering the potential of superposing the peak rate of the ground acceleration and water depth. The area of liquefied zones was estimated using the geographical information systems (GIS). The liquefaction risk classes has been estimated using risk equation considering hazard rate, elements at risk (e.g. roads, residential area and water resources) and their assigned vulnerability values in the case study area. According to the results, the North region of the case study had the highest risk class with dense residential communities and industrial activity, and also high groundwater table. Presented liquefaction vulnerability maps could be used as a basis for the hazard management and reducing future liquefaction losses. The implemented approach employed the intensity and range of liquefaction in collaboration with vulnerable elements to determine the liquefaction risk and make a scientific decision accordingly.