| 走滑断裂古地震探槽选址范例 |
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| 引用本文： | 袁兆德,刘静,李占飞,邵延秀,李志刚,王鹏,王伟,姚文倩.走滑断裂古地震探槽选址范例[J].地质通报,2016,35(11):1807-1828. |
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| 作者姓名： | 袁兆德 刘静 李占飞 邵延秀 李志刚 王鹏 王伟 姚文倩 |
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| 作者单位： | 1. 中国地震局地质研究所, 北京 100029;2. 中国地震灾害防御中心, 北京 100029;3. 中国地震局兰州地震研究所, 甘肃 兰州 730000 |
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| 基金项目： | 中国地震局行业专项（编号：201208006）、地震动力学国家重点实验室自主课题（编号：LED2014A02）和中国地震灾害防御中心主任基金（编号：201602） |
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| 摘 要： | 探槽选址直接决定了古地震研究的质量,且理想探槽位置具有稀缺性。在收集82篇国内外走滑断裂古地震研究论文的基础上,分析了长序列古地震探槽选址和同震位移探槽选址的构造地貌共性特征。长序列古地震探槽一般布设在断塞塘、拉分盆地、小型湖盆、闸门脊汇水一侧及比较平缓的冲洪积扇或大型冲洪积扇末端等地貌位置。这些地貌位置的共同特征是位于连续的、较高沉积速率的沉积环境,且通常富集14C测年物质。在探槽选址的过程中,不仅要对现今沉积环境,也要对其古地理环境进行评价。然而以发掘古地震同震位移为目的的探槽选址则不同,成功的研究点往往较频繁发生侵蚀和下切事件,其中冲沟是最常见的地貌标志。探槽布设以垂直和平行探槽为主,采取逐次掘进或相间平行排列的方式开挖。由于理想探槽位置的稀缺性,所以在这些优质的探槽点一定要开展长期详细地深入研究,最大限度获得古地震事件的长序列,同时也要注意新技术和新方法的应用。
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| 关 键 词： | 走滑断裂 古地震 探槽选址 高沉积速率 埋藏冲沟 同震位移 |
| 收稿时间： | 2015/12/9 0:00:00 |
| 修稿时间： | 2016/5/31 0:00:00 |
Tecto-geomorphic analysis of paleoseismic trenching sites on active strike-slip faults |
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| YUAN Zhaode,LIU Jing,LI Zhanfei,SHAO Yanxiu,LI Zhigang,Wang Peng,WANG Wei and YAO Wenqian.Tecto-geomorphic analysis of paleoseismic trenching sites on active strike-slip faults[J].Geologcal Bulletin OF China,2016,35(11):1807-1828. |
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| Authors: | YUAN Zhaode LIU Jing LI Zhanfei SHAO Yanxiu LI Zhigang Wang Peng WANG Wei and YAO Wenqian |
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| Institution: | 1. Institute of Geology, China Earthquake Administration, Beijing 100029, China;2. China Earthquake Prevention Center, Beijing 100029, China;3. Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 73000, Gansu, China |
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| Abstract: | Ideal trenching sites, which directly determine the quality of the paleoseismic research, are very rare. In this paper, based on 82 research papers of paleoseismic investigations published both in Chinese and English, the authors analyzed the common geomorphological characteristics of trenching sites that recorded long series of paleoearthquakes and coseismic slips. The sites with long paeloearthquake records are usually located at the sag pond, pull-apart basin, small closed basin, or upstream of a shutter ridge, a gentle fan or the toe of a large-drainage fan, which have common depositional environment with few or no depositional hiatuses, high rates of sedimentation, and abundant carbon dating materials. We should not only analyze the modern depositional environment but also its paleoenvironment during the choice of trenching sites. On the other hand, trenching sites for the purpose of recovering coseismic slips are often located at places where frequent incision events are recorded, such as channels, which provide offset piercing markers. In these studies, trenches are opened in an array with orientations both parallel and perpendicular to fault strike. Due to the fact that good trenching sites are rare, decade-long persistent efforts are usually invested at these sites for detailed studies, to uncover as many as possible the events back in time. |
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| Keywords: | strike-slip faults paleoearthquake trenching site high sedimentation rate burial channel coseismic slip |
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