【摘要】 通过地貌追踪、浅层地震、钻孔联合剖面勘探及探槽开挖等,查明了渭河断裂咸阳段(杨家村—窑店)的展布和最新活动时代。结果表明,渭河断裂咸阳段从咸阳市北侧渭河阶地前缘陡坎通过,考虑到断裂在金家庄、东耳村一带存在一个左阶斜裂区,阶区宽约1 km,可将断裂分为东、西两段,即:杨家村—金家庄段和东耳村—窑店段。断裂总体走向NE,倾向S,倾角65°~75°,为同生正断层。程家村探槽显示断裂错断全新统黑垆土底界15 cm,该层底界14C测年结果为2 255 BP,顶界光释光(OSL)年龄测年结果为(3.7±0.41)ka,说明断裂在全新世有活动。渭河断裂咸阳段自晚更新世以来活动性逐渐减弱,全新世平均活动速率为0.04~0.12mm/a。更多还原

【Abstract】 Based on the terrain tracking,the shallowearthquake,the drilling composition section exploration and the trench excavation etc.,we ascertained the distribution of Xianyang Segment( Yangjia Village-Yaodian) of Weihe Fault and its latest active period. The result shows that the Xianyang Segment of Weihe Fault passes through the scarp on the leading edge of Weihe terrace in the north of Xianyang City. Considering that there is a left order oblique fissure zone with the wide of about 1 km around Jinjiazhuang and Dong’er Village on the fault,the fault can be divided into two sections: the segments of Yangjia Village-Jinjiazhuang in the east and Dong’er Village-Yaodian in the west.The Xianyang Segment of Weihe Fault is a synsedimentary normal fault,and the overall trend and the tendency of it is NE and S respectively,and the dip angle of it is 65° ~ 75°. The exploratory trench in Chenjia Village displayed that the bottom boundary of the Holocene Heilu soil was dislocated about 15 cm by the fault. The14 C dating result of the bottom boundary was 2 255 BP and the result of age dating on Optically Stimulated Luminescence( OSL) of the top boundary was( 3. 7 ± 0. 41) ka,which indicated that the fault was active in the Holocene. The activities of Xianyang segment of Weihe Fault weakened gradually since the late Pleistocene,and its average active rate was 0. 04 ~ 0. 12 mm / a in the Holocene.更多还原