祁高_河南洛阳偃师断裂的空间展布与活动性分析.DOC

河南洛阳偃师断裂的空间展布与活动性分析 摘 要 偃师断裂为洛阳盆地内主要的第四纪断裂之一，东段出露于丘陵山区，西段隐伏于第四纪沉积物中，其展布特征和地震危险性尚不清楚，给周边城市的建设和发展带来隐患。本文通过对遥感影像、野外地质地貌调查和浅层地震勘探资料的综合分析，研究了偃师断裂的展布特征；并在此基础上，综合前人研究成果和历史地震资料分析了偃师断裂的活动性，并讨论了历史地震与该断裂的关系。研究结果表明：偃师断裂为整体走向近EW向，S倾的正断层，全长约55km。断裂东起偃师市朝廷沟，沿邙岭南缘向西经汤泉沟、偃师城北、平乐镇和凤台村南；凤台村以西则完全隐伏于第四纪沉积物中，至金水河一带与石陵—白鹤断裂相交。偃师断裂必威体育精装版活动时代为中更新世，并且很可能为公元前1767年6级地震及其它2次破坏性地震的发震断裂。 关键词：隐伏断层；浅层地震勘探；遥感；断层活动性；洛阳盆地 Spatial distribution and activity of yanshi fault in luoyang city, henan province Abstract: Yanshi fault is a major Quaternary fault in Luoyang basin, the eastern segment of the fault is exposed in the hilly, and the western of the fault is buried in Quaternary sediments. Its spatial distribution and activity are not clear, so there is a hidden danger to the development of the surrounding city. Based on the remote sensing image interpretation, shallow seismic exploration and geological survey, the spatial distribution and activity of the Yanshi fault are discussed in the paper. The relation between the historical earthquakes and the fault is also discussed. The results show that the near EW-trending Yanshi fault extends to Chaotinggou village in the east direction, and the fault at its west end is cut by the Shilling-Baihe fault. It is a South dipping normal fault with a total length of about 55km. The fault distributes along the south of Mangling, and passes through Tangquan village, north Yanshi city, Pingle village and south Fengtai village. The latest active time of Yanshi fault is in the Middle Pleistocene, and it might be the seismogenic fault of the M6.0 Yanshi earthquake of 1767 B.C. and other two destructive earthquakes. Key words: hidden fault; shallow seismic exploration; remote sensing; fault activity; Luoyang basin 1 引言 本文的研究区位处于洛阳盆地。该盆地北依邙山，南抵嵩山，西有小秦岭，中东部为伊洛河冲积平原，整体由西向东倾斜呈三面环山向东敞开的箕形地貌。盆地内横跨有多条第四纪隐伏断裂，但这些断裂的研究程度均不高。随着洛阳市及其周边城市的不断建设与发展，地震危险性评价工作显得十分的紧迫，查明活动构造的展布情况和活动特征，对于防御和减轻地震灾害有着非常重要的意义。偃师断裂位于邙山南缘，是洛阳盆地的北界断裂，断裂全长约55km，其确切的空间展布和必威体育精装版活动时间有待研究。 在城市活断层探测工作中，地表通常被第四纪松散沉积物所覆盖，浅层反射