Liquefaction Zonation of Lorestan Province

One of the most important problems in geotechnical projects is how to predict unstable areas. There are several methods to hazard potential delineation, generally include direct and indirect methods. In general, for some geotechnical problems, the hazard potential can be expressed by the terms of "very high, high, moderate, low, and very low". The evaluation using these terms as a qualitative assessment, enables the preparation of susceptibility maps at low cost for purposes such as land-use planning or regional risk assessment. This paper presents the investigation results of liquefaction zonation in Lorestan Province. This zonation is based on Forth Technical Committee manual for zonation on seismic geotechnical hazards (TC4). Three grades of approach to zonation can be used related to scale of mapping: Grade 1 or general zonation which is based on compilation and interpretation of existing information available from historic documents, published reports and other available databases, mapping in the range 1:1000,000 to 1:50,000. Grade 2 or detailed zonation, mapping to scales of about 1:100,000 to 1:10,000, based on improving the Grade 1 zonation maps at moderate cost by making use of additional data such as aerial photographs or additional field studies. Grade 3 or rigorous zonation, which is a very detailed level of zonation, mapping in scales of 1:25,000 to 1:5,000. In this paper, Lorestan Province Liquefaction Potential is evaluated bases on Grade 1 and Grade 2 methods and mapped in scale of 1:250,000. Results of this zonation shows that the potential of seismic hazsrds of alluviums in this region varies from low to high, related to soil structure, level of ground water and Soil density.