Risk Assessment Of Southern Segment Of Fuyu/Songyuan-Zhaodong Fault

Fuyu/Songyuan-Zhaodong fault is one of the most important faults in the northeast seismic region with the most seismic intensity and frequent.However,the activity of this fault is still unclear due to it is located in the Songliao basin,which belongs to concealed fault,being covered by Quaternary.Shallow artificial seismic survey is implemented on the southern segment of Fuyu/Songyuan-Zhaodong fault,based on the data of tectonic,neotectonic movement,deep geophysical data from petrol department and seismicity.Qianguo earthquake swarm of 5.8 magnitude in 2013 is also relocated by small earthquake precision positioning method.The seismogenic tectonic of Qianguo earthquake swarm of 5.8 magnitude in 2013 is also preliminary discussed in the paper.Finally,3-D finite element analysis is implemented to calculate the ground motion of southern segment of Fuyu/Songyuan-Zhaodong fault.The following conclusions can be drawn:(1)The data of tectonic,neotectonic movement,deep geophysical data from petrol department,seismicity,shallow artificial seismic exploration and magnetotelluric sounding are confirmed the existence of southern segment of Fuyu/Songyuan-Zhaodong fault,which overall along the direction of NE,trends to NW.(2)The southern segment of Fuyu/Songyuan-Zhaodong fault shows not active in the late Quaternary according to its characteristic of tectonic and neotectonic movement.The junction of Fuyu/Songyuan-Zhaodong fault and Chaganpao-Daozijing fault has intense seismicity and occurred Qianguo earthquake swarm of 5.8 magnitude in 2013.(3)Deep geophysical data from petrol department and the result of shallow artificial seismic exploration indicate that the southern segment of Fuyu/Songyuan-Zhaodong fault is a Pre-Quaternary fault.(4)The Chaganpao-Daozijing fault is the seismogenic tectonic of the Qianguo earthquake swarm of 5.8 magnitude in 2013,according to the earthquakes redistribution map by small earthquake precision positioning method.(5)The waveforms of Qianguo earthquake swarm of 5.8 magnitude in 2013,which containing abundant surface wave components,is obviously different from the traditional tectonic ones.Furthermore,the Chaganpao-Daozijing fault is small in size and cannot lead to a earthquake with 5.8 magnitude,according to the structural analogy method.The Chaganhua region is the high pressure water injection petrol exploration area,the Qianguo earthquake swarm of 5.8 magnitude in 2013 may be associated with the high pressure water injection.(6)3-D finite element analysis is implemented to calculate the ground motion of southern segment of Fuyu/Songyuan-Zhaodong fault,according to the investigation and activity research.The prediction result can provide basic reference for earthquake disaster prevention planning of Songyuan region.