significance of high-resolution loess stratification based on grain size and magnetic susceptibility analysis to paleo-earthquake study: a case study of dongyugou loess section, at hongtong, shanxi province

doi:10.3969/j.issn.0253-4967.2015.04.013

Abstract

Abstract:

As an important technology to paleoseismologic research, trenching has been used to identify paleo-earthquakes recorded in strata, combined with dating technology. However, there have been some bigger uncertainties and limitations. For instance, subtle strata in loess sediment cannot be interpreted only by naked-eye, which seriously affects identifying paleo-earthquake horizon and time. Therefore, how to improve the accuracy and reduce the uncertainty of paleo-earthquake identification is the important problem we are currently facing. Dongyugou loess section, located in the northeastern corner of Linfen Basin, Shanxi Province, cuts across the Huoshan piedmont fault. The section exposes not only the well-developed loess sequence, but also several obvious faulting events. Thus, this loess section is a better site to make a high resolution study to improve the accuracy and reduce the uncertainty of paleo-earthquake identification. Based on the high-resolution grain size and magnetic susceptibility analysis, and associated with visual interpretation by naked-eye, we made a high-resolution stratification of Dongyugou loess section, including high-resolution thickness of each stratum and its upper and bottom boundaries. Based on the high-resolution stratification and their comparison between two fault walls, we identified three earthquake events, which occurred after formation of u5-7, u4 and u2, corresponding to their stratification depth of 7.1m, 4.7m and 2.9m in hanging wall. Based on results of OSL dating and average sedimentation rate of hanging wall, we estimated that the three events occurred around 45.8ka(between (48.1±1.5)～(43.2±2.5)ka), 32.8ka(between (35.0±2.4)～(30.6±1.3)ka) and 23.3ka(between (26.4±0.8)～(20.9±0.7)ka). According to the thickness difference of three loess-paleosol sedimentary cycles between two fault walls, we calculated the coseismic vertical displacements of the three events as 0.5m, 0.4 and 1.3m, respectively. Compared with other segments of the Huoshan piedmont fault zone, we found the southernmost segment is the weakest, with longer recurrence interval of about 11ka and lower vertical slip rate of 0.048mm/a. The high-accuracy grain size and magnetic susceptibility analysis offers an effective method for reducing the uncertainties of the paleo-earthquake research in loess area.

Key words: paleoseismology, grain-size and magnetic susceptibility analysis, visual interpretation by naked-eye, Huoshan piedmont fault, Shanxi graben systems

摘要：

探槽技术虽然已经发展成为古地震研究的重要手段, 结合定年技术可以识别出古地震事件与地震重复间隔, 但是仍然存在较大的不确定性和局限性。例如, 目视解译难以区分黄土沉积内部的细层理, 严重影响了古地震事件发生位置或时间的判定。如何提高古地震研究的精度和准确性, 降低古地震事件判定的不确定性, 是目前面临的一个迫切问题。山西洞峪沟剖面位于山西临汾盆地东北角, 横跨霍山山前断裂带, 不仅揭示了较好的黄土沉积序列, 还揭露了明显的地层错断事件。因此, 该剖面是一个开展高精度探槽古地震研究, 降低判定古地震事件不确定性的理想场所。根据高精度的粒度与磁化率变化曲线, 结合目视分层解译结果, 对洞峪沟黄土剖面进行了精细分层, 界定了各层的厚度和边界。依据细分层和断层两盘地层的对应关系, 将u6层沉积以来的3次断错事件的发生位置和时间作了再限定, 它们分别发生在u5-7、u4以及u2的顶部, 对应断层上盘埋深7.1m、4.7m与2.9m。根据释光测年结果以及断层上盘地层的平均沉积速率, 推测3次断错事件发生的时间分别在 (48.1±1.5)～(43.2±2.5)ka BP接近45.8ka BP、(35.0±2.4)～(30.6±1.3)ka BP接近32.8kaBP、(26.4±0.8)～(20.9±0.7)ka BP接近23.3ka BP。根据3次黄土-古土壤沉积旋回的厚度差, 判定3次地震的同震垂直位移分别为0.5m、0.4m和1.3m, 累计位移2.2m。依据高精度粒度与磁化率变化曲线的地层分层方法, 为有效降低黄土地区古地震研究的不确定性提供了一种很好的参考。

关键词: 古地震研究, 粒度与磁化率分析, 目视分层, 霍山山前断裂带, 山西地堑系

CLC Number:

P315.2

WEI Lei-hua, HE Hong-lin, JIANG Han-chao, XU Yue-ren, WEI Zhan-yu, GAO Wei, ZOU Jun-jie. significance of high-resolution loess stratification based on grain size and magnetic susceptibility analysis to paleo-earthquake study: a case study of dongyugou loess section, at hongtong, shanxi province[J]. SEISMOLOGY AND GEOLOGY, 2015, 37(4): 1096-1114.

卫蕾华, 何宏林, 蒋汉朝, 徐岳仁, 魏占玉, 高伟, 邹俊杰. 黄土地区粒度与磁化率分层对古地震研究的意义——以山西洞峪沟黄土剖面为例[J]. 地震地质, 2015, 37(4): 1096-1114.

References

程绍平, 杨桂枝. 1991. 活断层研究中的槽探技术［J］. 世界地震译丛, 13(3): 1—10.
CHENG Shao-ping, YANG Gui-zhi. 1991. Trenching technology application to active fault research ［J］. Translated World Seismology, 13(3): 1—10(in Chinese).
邓起东, 汪一鹏, 廖玉华, 等. 1984. 断层崖崩积楔及贺兰山山前断裂全新世活动历史［J］. 科学通报, 29(9): 557—560.
DENG Qi-dong, WANG Yi-peng, LIAO Yu-hua, et al. 1984. Colluvial wedges of fault scarp and history of faulting on the Helan Shan piedmont fault ［J］. Chinese Science Bulletin, 29(9): 557—560(in Chinese).
胡小猛, 王杜涛, 陈美君, 等. 2014. 山西临汾盆地末次冰期时段湖相沉积中的H、 D/O事件记录［J］. 第四纪研究, 34: 354—363.
HU Xiao-meng, WANG Du-tao, CHEN Mei-jun, et al. 2014. The study of the records of H and D/O paleoclimatic events during the last glacial period from the lacustrine sediment in Linfen Basin, Shanxi Graben ［J］. Quaternary Sciences, 34: 354—363(in Chinese).
刘东生. 1966. 黄土的物质成分和结构［M］. 北京: 科学出版社.
LIU Dong-sheng. 1966. The Material Composition and Structure of Loess ［M］. Science Press, Beijing(in Chinese).
刘东生. 1985. 黄土与环境［M］. 北京: 科学出版社.
LIU Dong-sheng. 1985. Loess and Environment ［M］. Science Press, Beijing(in Chinese).
鹿化煜, 安芷生. 1997. 前处理方法对黄土沉积物粒度测量影响的实验研究［J］. 科学通报, 42(23): 2535—2538.
LU Hua-yu, AN Zhi-sheng. 1997. Experimental study on the influence of different pretreatment procedures on the particle-size measurement of loess sediments ［J］. Chinese Science Bulletin, 42(23): 2535—2538(in Chinese).
冉勇康. 1997. 我国几个典型地点的古地震细研究和大地震重复行为探讨［D］:［学位论文］. 北京: 国家地震局地质研究所.
RAN Yong-kang. 1997. Detailed research of paleoearthquakes at several typical regions in China and exploration of recurrence behavior of large earthquakes ［D］: Ph D Thesis. Institute of Geology, State Seismological Bureau, Beijing(in Chinese).
冉勇康, 邓起东. 1999. 古地震学研究的历史、现状和发展趋势［J］. 科学通报, 44(1): 12—20.
RAN Yong-kang, DENG Qi-dong. 1999. History, status and development of paleoseismology ［J］. Chinese Science Bulletin, 44(1): 12—20(in Chinese).
冉勇康, 李志义, 尤惠川, 等. 1988. 河西走廊黑河口断层上的古地震及年代学研究［J］. 地震地质, 10(4): 118—126.
RAN Yong-kang, LI Zhi-yi, YOU Hui-chuan, et al. 1988. The study and dating of paleoearthquake along Heihekou Fault in Hexi Corridor ［J］. Seismology and Geology, 10(4): 118—126(in Chinese).
田明中, 程捷. 2009. 第四纪地质学与地貌学［M］. 北京: 地质出版社.
TIAN Ming-zhong, CHENG Jie. 2009. Quaternary Geology and Geomorphology ［M］. Geological Publishing House, Beijing(in Chinese).
王克鲁, 盛学斌, 严富华, 等. 1996. 山西临汾盆地黄土及其形成古环境［J］. 地震地质, 18(4): 339—348.
WANG Ke-lu, SHENG Xue-bin, YAN Fu-hua, et al. 1996. The loess and the paleo-environment for its formation in the Linfen Basin of Shanxi Province ［J］. Seismology and Geology, 18(4): 339—348(in Chinese).
王旭龙, 卢演俦, 李晓妮. 2005. 细颗粒石英光释光测年: 简单多片再生法［J］. 地震地质, 27(4): 615—623.
WANG Xu-long, LU Yan-chou, LI Xiao-ni. 2005. Luminescence dating of fine-grained quartz in Chinese loess-Simplified multiple aliquot regenerative-dose(MAR)protocol ［J］. Seismology and Geology, 27(4): 615—623(in Chinese).
肖晨曦, 李志忠. 2006. 粒度分析及其在沉积学中应用研究［J］. 新疆师范大学学报(自然科学版), 25(3): 118—123.
XIAO Chen-xi, LI Zhi-zhong. 2006. The research summary of grain size analysis and its application in the sedimentation ［J］. Journal of Xinjiang Normal University(Natural Sciences Edition), 25(3): 118—123(in Chinese).
许洪泰. 2010. 探槽技术在古地震研究中的应用［J］. 华北地震科学, 28(3): 21—23.
XU Hong-tai. 2010. One way to expose paleoseismology trench ［J］. North China Earthquake Sciences, 28(3): 21—23(in Chinese).
徐锡伟, 邓起东, 韩竹君. 1993. 霍山山前断裂晚第四纪活动和古地震研究［A］. 见: 马宗晋主编. 山西临汾地震研究与系统减灾. 北京: 地震出版社. 136—148.
XU Xi-wei, DENG Qi-dong, HAN Zhu-jun. 1993. The late Quaternary activity of the piedmont fault of Mt. Huoshan and paleoearthquake study ［A］. In: MA Zong-jin(ed). Earthquake Research and Systematical Disaster Reduction in Linfen, Shanxi. Seismological Press, Beijing. 136—148(in Chinese).
徐锡伟, 计凤桔, 于贵华, 等. 2000. 用钻孔地层剖面记录恢复古地震序列: 河北夏垫断裂古地震研究［J］. 地震地质, 22(1): 9—19.
XU Xi-wei, JI Feng-ju, YU Gui-hua, et al. 2000. Reconstruction of paleoearthquake sequence using stratigraphic records from drill logs: A study at the Xiadian Fault, Beijing ［J］. Seismology and Geology, 22(1): 9—19(in Chinese).
徐岳仁. 2013. 山西霍山山前断裂带晚第四纪活动特征研究［D］:［学位论文］. 北京: 中国地震局地质研究所.
XU Yue-ren. 2013. A study on the late Quaternary faulting of the Huoshan piedmont fault zone in the central Shanxi faulted basin belt ［D］. Ph D thesis. Institute of Geology, China Earthquake Administration, Beijing(in Chinese).
张璞, 陈建强, 田明中, 等. 2005. 沉积物粒度分析在厦门市第四纪环境研究和地层划分对比中的应用［J］. 地球科学与环境学报, 27(1): 88—94.
ZHANG Pu, CHEN Jian-qiang, TIAN Ming-zhong, et al. 2005. Application of sediments grain-size analysis in Quaternary environmental research and its stratum compartmentalization and contrast function in Xiamen Island, Fujian Province ［J］. Journal of Earth Sciences and Environment, 27(1): 88—94(in Chinese).
张世民, 王丹丹, 刘旭东, 等. 2007. 北京南口-孙河断裂带北段晚第四纪活动的层序地层学研究［J］. 地震地质, 29(4): 729—743.
ZHANG Shi-min, WANG Dan-dan, LIU Xu-dong, et al. 2007. Sequence stratigraphy study of late Quaternary activities of Nankou-Sunhe Fault in its northern segment, Beijing ［J］. Seismology and Geology, 29(4): 729—743(in Chinese).
张宗祜, 张之一, 王芸生. 1989. 中国黄土［M］. 北京: 地震出版社.
ZHANG Zong-hu, ZHANG Zhi-yi, WANG Yun-sheng. 1989. Chinese Loess ［M］. Geological Publishing House, Beijing(in Chinese).
朱海之. 1979. 宁夏中宁发现古地震剖面［J］. 地震地质, 1(4): 26.
ZHU Hai-zhi. 1979. An ancient earthquake profile in Zhongning County, Ningxia Hui Autonomous Region ［J］. Seismology and Geology, 1(4): 26(in Chinese).
朱海之, 陈建英. 1982. 宁夏中卫古地震的若干特点［A］. 见: 中国地震学会地震地质专业委员会编. 中国活动断裂. 北京: 地震出版社. 282—290.
ZHU Hai-zhi, CHEN Jian-ying. 1982. Some characteristics of paleo-earthquakes in Zhongning County, Ningxia Hui Autonomous Region ［A］. In: Committee on Seismogeology, the Seismological Society of China(ed). The Active Faults in China. Seismological Press, Beijing. 282—290(in Chinese).
Aitken M J. 1998. An Introduction to Optical Dating ［M］. Oxford University Press, Oxford. 39—50.
Clark M M, Grantz A, Rubin M. 1972. Holocene activity of the Coyote Creek Fault as recorded in sediments of Lake Cahuilla ［J］. U S Geol Surv Prof Paper, 787: 112—130.
Sieh K E. 1978. Pre-historic large earthquake produced by slip on the San Andreas Fault at Pallett Creek, California ［J］. J Geophy Res, 83: 3907—3939.
Zheng H B, Huang X T, Ji J L, et al. 2007. Ultra-high rates of loess sedimentation at Zhengzhou since Stage 7: Implication for the Yellow River erosion of the Sanmen Gorge ［J］. Geomorphology, 85: 131—142.
Zhou L P, Shackleton N J. 2001. Photon-stimulation luminescence of quartz from loess and effects of sensitivity change on palaeodose determination ［J］. Quaternary Science Reviews, 20: 853—857.
Lu Y C, Wang X L, Wintle A G. 2007. A new OSL chronology for dust accumulation in the last 130, 000 yr for the Chinese Loess Plateau ［J］. Quaternary Research, 67: 152—160.

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