Assessment Of Regional Crustal Stability In Kuche Depression

Kuche Depression located in the cross-area of the Southern Tianshan and Tarim Plate. It is a Cenozoic foreland basin. The special position causes the region to form a zone with intense neotectonic movement and frequent destructive earthquakes. With the development of oil and gas economy in the area, the region has become a new economic zone in the South Xinjiang. So, it has significant importance that evaluating the crustal stability of Kuche Depression, which will not only to forecast evolutive trend of the geological calamities in the future but to reduce and prevent these disasters. And it also plays an important role in keeping sustainable economic development of Kuche area.The neotectoinc movements in the area have the characteristics of high deformation rate, a large amount of faults and new active age. And that, earthquakes with big magnitude and high frequency have took place in the area. So, activities of faults and earthquake are two fundamental factors on impacting in crustal stability of the region. Geological feature, earthquake activity, geophysics and faults activity are chosen as the main indexes for the assessment. For quality grades, four levels are used: stable, essential stable, sub-stable and unstable.The analysis of the crustal stability is based on a regional grid division, and a fuzzy comprehensive analysis method is used to determine the grade of the quality in each grid. The evaluation factors and their weights are taken from the results of the hierarchical analysis. The evaluation indexes consist of qualitative and quantitative ones. The qualitative ones can be quantified through the experts weighing system, while the quantitative ones can be obtained from statistical analysis.Based on the above-mentioned methods, the Kuche Depression is divided into nine zones with different quality grades.