地震研究

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0.04～0.12 mm/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 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. 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 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.

引言
1 研究区断裂展布
2 断裂活动性研究
3 结论与讨论

图1 渭河断裂勘探及其展布图<br/>Fig.1 Exploration of the Weihe Fault and its distribution

图1 渭河断裂勘探及其展布图
Fig.1 Exploration of the Weihe Fault and its distribution

图2 咸平路附近渭河断裂勘探图<br/>Fig.2 Exploration of the Weihe Fault near Xianping road

图2 咸平路附近渭河断裂勘探图
Fig.2 Exploration of the Weihe Fault near Xianping road

图3 W2测线地震反射叠加时间剖面<br/>Fig.3 Stacking time section of seismic reflection along W2 measuring line

图3 W2测线地震反射叠加时间剖面
Fig.3 Stacking time section of seismic reflection along W2 measuring line

图4 W2X测线地震反射叠加剖面图(道间距2 m)<br/>Fig.4 Stackeing time section of seismic reflection in W2X measuring line(group interval is 2 m)

图4 W2X测线地震反射叠加剖面图(道间距2 m)
Fig.4 Stackeing time section of seismic reflection in W2X measuring line(group interval is 2 m)

图5 程家村钻孔联合剖面图<br/>Fig.5 Drilling composite section at Chengjia Village

图5 程家村钻孔联合剖面图
Fig.5 Drilling composite section at Chengjia Village

图6 程家村探槽东壁素描图<br/>Fig.6 Interpretation map of the east wall of the trench at Chengjia Village

图6 程家村探槽东壁素描图
Fig.6 Interpretation map of the east wall of the trench at Chengjia Village

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备注

引言

1 研究区断裂展布

2 断裂活动性研究

3 结论与讨论

期刊信息