SEISMOLOGY AND GEOLOGY ›› 2013, Vol. 35 ›› Issue (4): 754-764.DOI: 10.3969/j.issn.0253-4967.2013.04.006

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LIU Yu-gang1, CHEN Tao2, MIN Wei1, ZHOU Ben-gang1   

  1. 1 Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2 Earthquake Administration of Zhejiang Province, Hangzhou 310013, China
  • Received:2013-09-21 Revised:2013-09-21 Online:2013-12-30 Published:2014-01-03


刘玉刚1, 陈涛2, 闵伟1, 周本刚1   

  1. 1 中国地震局地质研究所, 活动构造与火山重点实验室, 北京 100029;
    2 浙江省地震局, 杭州 310013
  • 基金资助:

Abstract: Many NW-trending faults are developed in West Shandong. Cangshan-Nishan Fault,about 130km long,striking 310°~340°,dipping to SW and NE with dip angle 70°~80°,is the largest one among these faults. According to geomorphological characteristics and relationship between fault and Quaternary deposits,Cangshan-Nishan Fault can be divided into three segments: the western segment(Fangshan-Tianhuang segment),about 30km long,controlling the western margin of Qufu Basin; the middle segment in the bedrock area(Tianhuang-Ganlin segment),about 80km long,forming a valley and controlling evolution of Baiyan River; and the eastern segment(Ganlin-Cangshan segment),buried in the Quaternary basin,about 20km long.
The western segment(Fangshan-Tianhuang segment)appears as a linear scarp in the satellite images. Field investigation shows that the linear scarp is mainly composed of rock with 2~5m high in topography. On the northeast side of the scarp is mountains composed of Archaeozoic Taishan group gneiss,and on the south-west side is late Pleistocene alluvial fan. A lot of profiles reveal that the late-Pleistocene deposits(the thermoluminescence dating results)are dislocated by the fault. The fault cross sections near the Qufu city show it is a normal fault with high scarps. The highest scarp is 4.7m high and the normal vertical slip rate is 0.07mm/a. However,the fault cross sections near the Tianhuang Town show it is a reverse fault with high dip angle. The highest scarp is about 1.5m high, lower than that near the Qufu city. All these information indicate that the fault,from west to east,is changed gradually from normal feature to reverse feature,and the height of fault scarp is decreased gradually from west to east.
Based on reported results in this area,Cangshan-Nishan Fault is a left-lateral strike-slip hinge fault. The results presented in this paper suggest that the western segment is dominated by normal dip-slip with left-lateral strike-slip component,the middle segment is dominated by left-lateral strike-slip with reverse dip-slip component. As the axes of hinge fault,the middle segment is the most active segment of Cangshan-Nishan Fault. Besides Cangshan-Nishan Fault,a series of NW-trending faults are developed in West Shandong with weak activity since late-Pleistocene. Many moderate-strong earthquakes are related to these NW-trending faults. We thus think these NW-trending faults have capability of generating moderate-sized quakes.

Key words: Cangshan-Nishan Fault, late-Pleistocene, geomorphic scarps, normal fault

摘要: 苍山-尼山断裂是鲁西地区多条NW向断裂中规模最大的一条,全长约130km。根据断裂沿线的地形地貌特征以及断裂与第四系的关系,可将其分为西、中和东3段。西段控制曲阜和田黄盆地的北界,全长约30km,卫星影像上线性特征清晰,地貌上都为高2~5m的基岩陡坎,陡坎NE侧为泰山群片麻岩,SW侧为第四纪洪积扇。沿断层陡坎多个地点发现断错测年结果为晚更新世地层的断层剖面,曲阜附近断层剖面显示为正断层,断层陡坎较高,最高4.7m,垂直正断滑动速率约为0.07mm/a。田黄附近断层剖面显示为高角度逆断层,断层陡坎高度低于曲阜附近,最高1.5m。因此,从西向东,断层性质由正断逐渐转为逆断,断层陡坎高度也由西向东逐渐降低。结合前人对苍山-尼山断裂的研究成果,表明该断裂是一条左旋走滑枢纽断裂,西段以正走滑为主,中段以走滑为主,为枢纽轴部,活动性最强。鲁西地区除苍山-尼山断裂外还发育多条NW向断裂,晚更新世以来都曾有过活动,但活动性都较弱,该地区历史上曾发生过多次5级左右的中强地震,断裂与历史地震活动的特点说明鲁西地区NW向晚更新世活动断裂为中强地震的发震构造。

关键词: 苍山-尼山断裂, 晚更新世, 地貌陡坎, 正走滑断裂

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