山西交城断裂带多个大探槽全新世古地震活动对比研究  

COMPARISON STUDY ON HOLOCENE PALEOSEISMIC ACTIVITIES AMONG MULTI-TRENCHES ALONG THE JIAOCHENG FAULT ZONE,SHANXI

作　　者：谢新生[1] 江娃利[1] 孙昌斌[1] 闫成国[1] 冯西英[1] 

机构地区：[1]中国地震局地壳应力研究所,北京100085

出　　处：《地震地质》2008年第2期412-430,共19页Seismology and Geology

基　　金：国家发展与改革委员会发改投资"城市活断层试验探测"项目(20041138)资助

摘　　要：介绍了沿交城断裂带5个地点开挖探槽揭示的古地震情况。这5个大探槽分别沿交城断裂带北、中、南段分布,其中北段和中段各有2个地点,南段1个地点,探槽之间相距11～35km。位于该断裂带北段和中段的4个探槽出露了断错全新世地层的断面,在这4个探槽中,位于断裂带北段的西张探槽和位于断裂带中段的新民探槽揭示的全新世3次古地震事件可进行对比,具有活动的同步性。由此显示交城断裂带的中段和北段在距今3060～3740a、接近5910a及8530～8560a期间,曾发生3次有地表破裂的古地震事件。位于断裂带北段的冶峪探槽,由于探槽位于台地内冲沟右旋扭曲处,断错的最新地层的年代距今10730a,其它断面断错晚更新世地层。位于断裂带中段的上固驿探槽地处洪积扇,断层带宽70m,断层走向N58°～74°E,断错的最新地层距今11570a,揭示了NEE向田庄断层晚更新世时期的活动。位于断裂带南段窑头探槽所在的原始地形受到人工改造影响,探槽剖面揭示全新统覆盖在显示距今3.0～3.5万年期间受到断裂活动影响的地层之上。交城断裂带5个地点的探槽开挖结果显示,该断裂带全新世时期的活动自南向北迁移。The paleoseismic situation revealed by the trenches excavated at five locations along the Jiaocheng Fault zone is introduced in this paper. These five big trenches locate at the northern,central and southern segments of the Jiaocheng Fault zone. Two exploratory trenches were dug at the northern and central segments of the Jiaocheng Fault zone each,and one trench on the southern segment. The distances among these five trenches are 11 - 35km. Four trench sections where dislocated Holocene strata are exposed lie in the northern and central segments of the fault. Among the four trenches, three Holocene paleoearthquakes are revealed by the Xizhang trench and the Xinmin trench,respectively in the northern and central segments of the fault. These three events are comparable and the activities are coeval. This shows that three paleoearthquake events with surface rupture occurred respectively in 3060 - 3740a BP,5910a BP and 8530 - 8560a BP in the central and northern segments of the fault. The Yeyu trench lies in the northern segment of the fault. Because it is located at the dextral distortion of a gully on the terrace, the age of the youngest stratum dislocated is about 10730a BP, and the late Pleistocene stratum is dislocated by other fault planes. The Shangguyi trench lies in the central segment of the fault on the alluvial-diluvial fan, where the width of the fault zone is 70m and the strike of the fault is N58° -74°E,the age of the youngest stratum dislocated is about 11570a BP. The trench reveals the late Pleistocene activity of the NNE trending Tianzhuang Fault. The Yaotou trench lies in the southern segment of the fault at the place where the primal terrain was effected by human reconstruction, the profile of the trench reveals that Holocene stratum overlies the stratum influenced by the fault activity during about 30 - 35ka BP. The trenches excavated at five locations along the Jiaocheng Fault zone show that the activities of the fault zone migrated from south to north during Holocene.

关 键 词：古地震 全新世 探槽 交城断裂带 山西 

分 类 号：P315.2[天文地球—地震学]