The Analysis Of And Seismic Activity About The Dadu River Fault

Dadu river area across Kangdian SN trending structural zone and Jintang arcuatetectonic belt,long-term tectonism、M etamorphism、and Magmatism,Specialstructural pattern formed mainly by the NE, NW direction, SN-trending structural zoneconstitutes a "Y" shape.Dadu River fault in the traditional sense means roughly north-south along theDadu River near extending distributed fault Kangdian shaft portion, some people as apart of the northern extension of the Anning River fault zone.Dadu River fault zonenorth from near Kangding impregnable, was impregnable arc structure are covered,south through Luding, Lengqi, Detuo, in the vicinity of asbestos Tianwan peanut shedthe cut Xianshuihe fracture, is about135km.As the elongation at break is longer, maybe different in different parts of the nature, characteristics and activity are not the same,mainly based on differences in fracture characteristics and activities of this article willbe divided into three sections Dadu River fault: the northern section-Changchang faultzone, the middle-Luding fracture (ductile shear) zone and the southern section-Detuofault.Were described as follows:1.Changchang fault: Changchang fault rupture of three components, namelyChangchang fracture, Loushang fault and Guadagou fault. This3faults extends almostparallel, structural characteristics and activity are very similar, so this article is dividedinto these three faults with a fault, and Changchang fault.Changchang fault zone northof Kangding County Dahuodi, the south side of the dam by the bitter collapseBailiangzi to Maibeng Township of Kangding County, beyond the east of LudingCounty Xuerliangzi, a total length of43km.Overall fracture eastward dip angles steepboundary between60°-80°. The main fault zone cutting Proterozoic-Paleozoic strata,stereotypes in Indo-Yanshan period, the performance of the grounds east to westoverthrust brittle deformation.Three main fault characteristics and activity aredescribed as follows:(1)Changchang fault performance by east to west overthrust brittle deformation tends to be more stable, generally eastward tilt, tend to range between70-88°, ChangChang fracture overall steeper inclination, between50overall between-70°, thefracture of a brittle fault gouge formed, Loose rocks, broken porphyry, breccia structureseries of fault rocks brittle deformation in the fault zone. Stereotypes in Indo-Yanshanperiod, since no significant activity in the Pleistocene.(2)Guadagou fault: Guadagou western margin of the Yangtze Kangdian axis insidethe secondary faults, from north to south, the total length of about22km. Overalleastward tilted fault, east to west by overthrust brittle deformation tends to be morestable. But along different parts of the strike on, there is a certain tendency to change.South along the fault tendency to suffer Bailiangzai South-East, the northern end of thefive fault dip temple area east and south to the estuary area, faults tend to east, in theditch along Guarda, faults tend to NEE-East. However, the overall tendency between60-80°, dip angle, ranging between60-70°Overall, stereotypes in Indo-Yanshanperiod, since the Pleistocene no significant activity.(3)Loushang fault: fracture upstairs extends north-south direction along the leftbank of the Dadu River in general, the more obvious characteristics of horizontalalignment, slightly undulating on the go. Tend to break more stable overall eastward dipof moderate-steep. Loushang fault is a thrust faults, is Indo-product overthrust roleYanshan formation. What is the Pleistocene period, the Pleistocene since no significantactivity.2. Luding ductile shear zones: Luding rupture of an ancient ductile shear zonewidth of500-1000m, to the south by the Huashibao, Zhimatuo cut Moxi fault rupture,exposed length about40km. The overall trend north-south faults, west-dipping, dip50°-70°. Luding ductile shear zone formed mainly with Jinningian-ductile shearingChengjiang period, since the late Pleistocene was no significant activity.3. Detuo fault: fault north of Detuo Dadu right bank of Luding lengqi mill ditch500m, to the south by the Huashibao, Zhimatuo, asbestos coated boulders cut Moxifault rupture, the exposed length of about40km. The overall trend north-south faults,west-dipping, dip50-70°. Scan through the quartz morphology and ESR dating shows,Detuo fautl does not have proper fault activity.