论文部分内容阅读
齐心庄探槽位于 1679年三河 -平谷 8级地震夏垫地表地震破裂带东段。探槽内出露的断错地层、崩积楔、堰塞塘堆积、张裂楔及微细地层层理的揉皱现象 ,显示夏垫断裂全新世以来曾发生 4次强震事件。这 4次强震分别发生在距今 ( 10 85～ 9 71)ka、( 7 39～ 6 68)ka、( 5 4 16～ 2 2 33)ka及 1679年 (即三河 -平谷 8级地震 )。这 4次强震的时间间隔分别为 ( 3 2 4 5± 0 336)ka、( 3 2 11±0 815)ka及 ( 3 553± 0 796)ka ,平均强震间隔为 ( 3 336± 0 396)ka。 4次强震的平均同震垂直位移为 ( 1 4± 0 5)m。在齐心庄实施的探槽工程 ,除邻近断面开挖的探槽外 ,还在探槽南北 4 0 0m范围内开挖了 4个探坑 ,对认识断层下降盘地层的展布形态及确定断面堰塞塘的分布提供了帮助。在这些野外工作基础上 ,对齐心庄探槽研究结果与前人沿夏垫断裂其它地点的探槽及钻孔资料进行了对比 ,在古地震事件认识上大部分是一致的。
Qixinzhuang exploration trough located in the 1679 Sanhe - Pinggu 8 earthquake summer cushion surface earthquake rupture zone eastern section. Faults exposed in the trench, stratigraphic wedges, weir ponds, cracked wedges, and fine stratification of crumpled bedding reveal that there have been 4 strong earthquakes since the Xia mat fault. These 4 strong earthquakes occurred respectively from 10 85 to 9 71 ka, from 7 39 to 6 68 ka, from 5 4 16 to 2 2 33 ka and from 1679 (ie, the Miehe-Pinggu M8 earthquake) . The intervals of these 4 strong earthquakes are (3 2 4 5 ± 0 336) ka, (3 2 11 ± 0 815) ka and (3 553 ± 0 796) ka, respectively. The average strong earthquakes interval is (3 336 ± 0) 396) ka. The average coseismic vertical displacement of the 4 strong earthquakes was (1 4 ± 0 5) m. In Qixinzhuang trenching project, besides the trenches excavated near the section, four exploration pits were also excavated within 400 meters from north to south of the trenches. It is of great significance to understand the distribution pattern of the descending layer of the fault and confirm the section Weir pond distribution has provided help. Based on these field work, the results of the alignment of Xinzhuang exploration trenches are compared with that of the exploration trenches and boreholes along other locations of the summer mat fault, and most of them are consistent in the understanding of paleoearthquakes.