Numerical Simulation On Tectonic Stress Field Of Areas Near Yishu Fault Zone

On the basis of understanding the general geological conditions about Yishu FaultZone, this article is committed to numerical simulation of tectonic stress field nearYishu Fault Zone, so as to analyze characteristics of tectonic stress field in theregionand. The study of tectonic stress field is to reveal the stress distribution andvariation within a certain range, accurately reflect the situation in the region of force,and better understand regional tectonic movement pattern, structural development andso on, and finally for seismic hazard prediction has some significance. The finiteelement method is widely used in geoscience and other fields of engineering sciencesas its result is reliability. There are five basic steps to realize finite element numericalsimulation: the main model, parameter setting, model discretization, set up the initialconditions and boundary condition, solve the stiffness matrix.Yishu Fault Zone is part of Tanlu Fault Zone in Shandong province. Tanlu FaultZone is the famous shell deep fault belt in eastern part of our country, which is also astrong earthquake belt in eastern China. Yishu Fault Zone comes from Xiyi of Jiangsuprovince via Tancheng to Changyi and end in Bohai sea, through partial easternShandong, average to17°,330km long. This fault zone is mainly composed byChangyi-dadian、Anqiu-juxian、Yishu-tangtou、Tangwu-gegou four active fractures.The area near Yishu Fault Zone has occurred70BC Anqiu7earthquake and1668earthquake Tancheng8, and scholars believed that Anqiu-Juxian fracture is themain seismogenic fault.This paper established a3-D linear elastic geological model, Yishu fault zone asthe center, covering almost the entire Shandong province. Of this model containsmultiple fractures, and a number of secondary faults, and setting the fracture strike,dip, dip and other geometric parameters based on geological data, using hierarchicalblock partitioning given physical parameter values, to make the model close to thereal situation as much as possible.In a combination of geological, seismic, geophysical data on the regionalframework and build a three-dimensional geological model of elastic，using GPSobservations in the study area as constraints and inspection standards, through finiteelement numerical simulation software ANSYS12.0，analyzed the regional tectonicstress field and deformation characteristics of today’s field, and then explored thedynamics of the mechanism, and discussed the seismic hazard prediction near Yishufault zone.From the overall research to the path of research areas, the results are equal tobackground field with the principal stress direction as NEE to the main compressivestress field. During2009-2013the principal stress direction almost NEE near EW, butsome part area occurred NW. In displacement field, the direction from SE to NE.Local structure properties of local analysis, fault and predecessors’ research, arestrike-slip faults.