Shut The Relationship Between Seismic Activity And Tectonic Activity

Activity character of regional earthquake and earthquake movement law are researched in this paper on the base of analyzing regional structure and gravity-magnetic abnormity characteristics. The analyzing aboved is made from earthquake's space distributing, periodicity, migration phenomenon, repetition, strength, frequency, b value etc., according to data of earthquake station net in Shaanxi Province and microseisms station net watching results in Xi'an area. 3 group faults which are NEE, NW and EW direction control earthquake activities in Guanzhong area. Epicenter depth mostly is 5-25km and in shallow-focus earthquake. Earthquake in east area of Guanzhong was stronger and weaker in the West in history. Fen-Wei earthquake belt showed more activity. Microseisms and small seisms is main movement in recent earthquake, it has 8-10years' period of movement and show the trend that they are strong in the West but weaker in the East. And frequency and biggest magnitude of earthquake is supplement each other. In next years earthquake frequency will lessen but strength enhance, about M4. It presumes there is earthquake climax period in Guanzhong area in 2040 and M5-6 earthquake is happened at that time.Analyzing the relation between earthquake and structure distortion, main fault belt, crust, upper mantle, ground fracture, hotspring, geotherm, conductance frame, stress state in Guanzhong area is analyzed with earthquake mechanism, isoseismal line, crustal stress measure, fault displacement measure, and simulating test results. Earthquake formation mechanism is discussed with dynamics mechanism in Guanzhong base. There are 3 forces and a good medium environment, which are main reasons caused earthquake happened in Guanzhong area. The first force is NE and NEE level extrusion one which is parallel with long axis of Guanzhong base. The second one is level strain which is vertical with long axis of the base. The third one is mantle upper emerging. High conductive layer is a good medium environment.There is trend forecast of earthquake fatalness of Guanzhong area and near, taking Xi'an city as the center and discussing earthquake infection. 7 earthquake danger parts are ploted in this area, which is Lintong- Chang'an district, Huaxian-Lantian district, Chaoyi district, Bahe district, Hancheng district, Longxian district, Wugong district. They are key regions for earthquake watching in recent even long period time. Region stability of Xi'an city is evaluated , carved up and judged with fuzzy clustering analyzing of maths. Xi'an city development trend should be in the direction of the West and the Southwest according to analyzing results aboved.