EFFECTS OF 414 YUSHU EARTHQUAKE IN QINGHAI ON GEOLOGICAL ENVIROMENT

On April 14, 2010(4.14),a Ms 7.1 earthquake happened in Yushu county,Qinghai province.It not only damaged many buildings in Yushu county and buildings in a certain scope of perimeter area,but also induced a series of geological environmental issues.These issues include triggering geological hazard,destroying geomorphology landscape,breaking formation of water-bearing stratum,changing the groundwater flow field,surface rupture,and changing the physical properties of rock-soil.A great deal of field investigations show that: firstly,the geological environmental issues should be represented as collapses,landslides,debris flow and potentially unstable slopes,earthquake surface ruptures,mountains cracks,and shaking compaction,earthquake liquefaction,and damages to cultural relics and geomorphologic landscapes; Secondly,this paper shows the features of geologic hazards distribution including the spatial features of collapses,landslides,debris flows and potential unstable slopes,in order to analyze how the earthquake geologic influences on the geologic environment.And statistics show that the influence scopes of the 4.14 earthquakes upon geologic environments has a close relationship with the length of the surface ruptures and the position of hanging wall and footwall; Thirdly,Taking structure surface of earthquake rupture as a reference,the destroying geologic environment can be divided into three parts: more serious area,serious area and general area.Such classification combines the features of geologic hazards distribution,for the purpose of making out correspondingly effective measurements and thoughts for administrating and investigating geologic hazards after earthquakes; Fourthly,there are many paleoearthquakes distributed along the earthquake fault zone.And most of them were thrown about.Thereby,through the comprehensive analyses of the effects of Yushu earthquake upon the geologic environment,relevant effective emergent measurements for inspection and examination are accordingly made in consideration of geological function induced by earthquake.As well as the administrative regions and technique ideas for earthquake stricken area are contoured and formulated.