| 银川盆地东缘黄河断裂第四纪活动与分段性研究 |
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| 引用本文：包国栋,陈虹,胡健民,朱桂繁.2019.银川盆地东缘黄河断裂第四纪活动与分段性研究[J].地球学报,40(4):614-628. |
| DOI：10.3975/cagsb.2019.010501 |
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| 基金项目:中国地质科学院基本科研业务费专项经费“贺兰山东麓山前断裂活动性调查研究与监测”(编号: YYWF201616);中国地质调查局地质调查项目“特殊地质地貌区填图试点”(编号: DD20160060) |
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| 中文摘要:银川盆地位于南北地震带的北段, 是一个典型的新生代断陷盆地, 自西向东发育贺兰山东麓山前断裂、芦花台断裂、银川隐伏断裂和黄河断裂等四条主要活动断裂。该盆地中记载的历史最大地震是 1739年平罗8级地震, 其发震断裂一直存在争议, 最近研究认为可能是黄河断裂, 但是缺乏直接的古地震证据。本文通过对黄河断裂的地貌特征、几何分布、构造变形序列和地震活动等方面的研究, 发现黄河断裂可以划分为红崖子段、陶乐段、滨河段和灵武段。断裂总体经历了早期由东向西逆冲变形向晚期西倾正断层的转换, 构造应力场由NW–SE向挤压转变为EW向伸展, 转换时间为晚更新世末。通过断裂不同位置活动性分析发现, 黄河断裂在晚更新世末—全新世期间至少经历了5次古地震事件, 其地震活动间隔约为 3 000 a。其中滨河段的最新活动是在4 000 a以前, 而陶乐段的最新活动可能在(330±30) a BP之后, 对研究1739年平罗8级地震的发震断裂具有重要的意义。 |
| 中文关键词:银川盆地 黄河断裂 第四纪 活动性 古地震序列 |
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| Quaternary Activity and Segmentation of the Yellow River Fault of the Eastern Margin of Yinchuan Graben |
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| Abstract:The Yinchuan Graben is located in the northern segment of the South-North Seismic Belt. It is a typical Cenozoic fault basin. It develops four major active faults: the Helan piedmont fault, the Luhuatai fault, the Yinchuan buried fault and the Yellow River fault from the west to the east. The largest earthquake recorded in the basin is the Pingluo M8.0 earthquake of 1739, and its seismogenic fault has been controversial. Recent studies suggested that the seismogenic fault may be the Yellow River fault, but there is no direct paleoseismic evidence. Based on the study of the geomorphological characteristics, geometric distribution, tectonic deformation sequence and seismic activity of the Yellow River fault, the authors hold that the Yellow River fault could be divided into Hongyazi section, Taole section, Binhe section and Lingwu section. The faults underwent an transformation from the early thrust deformation from east to west to the late westward dipping normal faults. The tectonic stress field changed from NW–SE compression to nearly EW extension, and the transformation time was the end of late Pleistocene. According to the activity analysis of different locations of the fault, the Yellow River fault experienced at least 5 paleoseismic events during the Late Pleistocene–Holocene period, and the interval of seismicity was about 3 000 years. The latest activity time of the Binhe section was 4 000 years ago, and the latest activity of the Taole section occurred later than (330±30) a BP, it is of great significance to study the seismogenic faults of the Pingluo M8.0 earthquake of 1739. |
| keywords:Yinchuan Graben Yellow River fault Quaternary activity paleoseismic sequence |
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