阳曲断陷盆地西界断裂带活动特征及对盆地构造演化的指示OA

Through shallow seismic exploration and controlled source audio-frequency magnetotelluric method,typical geophysical profiles of the western boundary fault zone in Yangqu rift basin are given,and fine fault structural profile characteristics are obtained.The results show that the fault zone can be divided into the north-ern and southern sections,with Wujiazui-Matou village as the boundary.The north section is Panlong-Gang-shang fault zone,with NW strike and length of about 13 km.The south section is the east side fault zone of Qizi mountain,with SN strike and length of about 20 km.Four main branch faults are developed in the south and north sections.Controlled by branch faults,multiple secondary horsts and secondary depressions are formed in the rift basin along the east-west direction.The results of joint drilling profile and stratigraphic chro-nology test show that the latest activity age of the southern section of the fault zone is late Pleistocene,and the minimum buried depth of the upper breakpoint is 21.1 m,the maximum fault distance is 3.9 m,and the maxi-mum sliding rate is 0.158 mm/a.The results can be used as an important reference for the evolution of Tai-yuan basin,the source exploration of large earthquakes,and the seismic risk analysis.