渭河断裂咸阳段活动性研究  

Research on Activities of Xianyang Segment of Weihe Fault

作　　者：田勤虎[1] 段蕊[1] 李晓妮[1] 卞菊梅[1] 魏青珂[1] 

机构地区：[1]陕西省地震局,陕西西安710068

出　　处：《地震研究》2015年第2期250-256,333,共7页Journal of Seismological Research

基　　金：中国地震局地质研究所基本科研业务费专项(IGCEA1220);陕西省自然科学基础研究计划(2011JM5012);中国地震局地震科技星火计划项目(XH13023Y);陕西省防震减灾"十一五"重点项目"咸阳市活断层探测与地震危险性评价"(SCZC2008)联合资助

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。Based on the terrain tracking, the shallow earthquake, 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 krn 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. The 14C 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 Holoeene. 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.

关 键 词：渭河断裂 浅层地震 钻孔联合剖面 探槽 全新世活动断裂 

分 类 号：P315.2[天文地球—地震学]