Study On Regional Crustal Stability And Prediction Of Earthquake Geological Hazards In The Lushui Section Of The Hejiang Gorge Area, Yunnan Province

In this paper, based on the regional crustal stability quantitative evaluation methods and principles to study of Lushui county in Nujiang valley of Yunnan province area of Regional crustal stability and Earthquake-induced geological disasters. The study includes regional geological background, geophysical characteristics, the neotectonic movement, seismic activity, the geology hazards’ distribution and slope analysis of geological disasters in six aspects, in order to evaluate based on the structural stability combination of ground-based stability assessment and medium stability the method of evaluation, fuzzy mathematical analysis of the regional crustal stability comprehensive analysis and evaluation, combined with the mechanism of the earthquake area and slope stability analysis using GIS structure of secondary geological disasters earthquake risk prediction.The regional crustal stability assessment using uniform grid method in Lushui county is divided by the density of 300m * 300m, selection of the crustal surface structure, characteristics of gravity field, fault influence zone, latest fault active age, macro seismic hazard, magnitude of potential earthquake source region, potential maximum seismic intensity, geological hazard development, geological hazard degree, human engineering activities, topographic gradient, rock and soil types, slope stability, water erosion 14 evaluation factors using fuzzy mathematical evaluation method, the calculation results are divided into relatively stable, relatively minor stable, relatively unstable and relatively unstable four kinds of stability by using the method of evaluating the value of layer area for regional crustal stability comprehensive stack. The evaluation results show that the regional crustal relatively unstable areas are mainly concentrated in the south along the Nujiang on both sides and Pianma area, overall stability degree from low to high outward from both sides of the Nujiang outward is oval shaped circle structure changes, relatively stable area along the Gaoligongshan and Biluxieshan mountain chain area. Comprehensive research results showed that alpine valleys of regional crustal stability is poorer areas are mainly concentrated in the valley position that the slope toe is easily flow erosion of position, these areas are also usually faults more frequent activity level areas, and usually more than the fractured zone.The earthquake-induced geological disasters prediction research is on the basis of the regional crustal stability assessment, select the damage degree of earthquake wave slope to the effect, terrain slope, slope structural stability, macro seismic hazard, slope type, seismic energy released six influence factors, through weighted superposition, using the ArcGIS spatial analysis of raster calculator weighted superposition calculation and will result in natural discontinuities classification earthquake-induced geological disasters forecast hazard zoning evaluation results. Due to the uncertainty of time and space of data overlay, predicting the risk zoning evaluation without considering rainfall conditions on the vibration influence on the stability of the slopes, according to the time distribution of geological disasters, if the earthquake occurred in June to August monsoon season, the situation will be more severe than predicted. Under the condition of without considering rainfall conditions, only in the earthquake effect caused by the earthquake-induced geological disasters forecast hazard assessment results in conformity with the regional crustal stability zoning results coincide roughly. Distribution according to earthquake-induced geological disasters risk prediction was mainly affected by three factors: The first is the distance from potential seismic source area and the size of the epicentral distance; The second is the slope gradient; The third is the water system distribution is closely related to the cutting action of the slope.Through analyzing the Nujiang valley area Lushui of regional crustal stability assessment and predictive risk zoning of earthquake-induced geological disasters evaluation results, It is concluded that the fault tectonic activities and high and steep slope formed by erosion of water system plays an important role in the regional crustal stability assessment and earthquake-induced geological disasters. Since the study involved the deep content and a wide range of research results, but also because of the results obtained are limited by the technical means and the subjective analysis, the paper still many shortcomings.