南海东部俯冲洋脊区段地震静态库伦应力分析

发布时间：2018-01-03 01:16

本文关键词：南海东部俯冲洋脊区段地震静态库伦应力分析　出处：《海洋地质与第四纪地质》2016年05期 　论文类型：期刊论文

【摘要】：根据对马尼拉海沟及其邻区地震分布和震源机制解所反映的最大主压应力轴分布特征的分析,并结合古洋脊俯冲区段地震产生的静态库伦应力分析,发现在马尼拉海沟区域地震分布具有明显的分带特性,北部以NW向挤压应力为主,俯冲洋脊区段以近EW向的挤压应力为主;1999年7.2级地震使得2000年6.2级地震和2011年6.0级地震震中位置的静态库伦应力分别增加了约0.5和0.3bar;2011年6.0级正断型地震和5.0级余震的静态库伦应力变化能较好地反映与余震分布的对应关系,大部分余震位于库伦应力变化值大于0.1bar的触发阈值区域;计算古洋脊俯冲区段强震产生的静态库伦应力变化,结果显示海沟西侧小于10km的深度范围内库伦应力增加值达到0.3~0.5bar,呈NE向展布,吕宋岛弧一侧20km深度范围内均表现为应力增加,应力增加区域与地震的分布较为吻合。
[Abstract]:Based on the analysis of the distribution of the maximum principal compressive stress axis reflected by the seismic distribution and focal mechanism solutions in the Manila trench and its adjacent areas, and combined with the static Coulomb stress analysis of earthquakes in the paleo-oceanic ridge subduction zone. It is found that the distribution of earthquakes in the Manila trench is obviously zonation with NW compressive stress in the north and near EW in the subduction ridge. The M = 7.2 earthquake of 1999 increased the static Coulomb stress of the epicenter of the M _ S6.2 earthquake of 2000 and the earthquake of M _ S 6.0 on 2011 by about 0.5 and 0.3 barrespectively. The static Coulomb stress variation of M = 6.0 positive fault type earthquake and M = 5.0 aftershock on 2011 can well reflect the corresponding relationship with aftershock distribution. Most aftershocks are located in the trigger threshold region where the Coulomb stress variation value is greater than 0.1 bar. The static Coulomb stress changes caused by strong earthquakes in the paleo-oceanic ridge subduction zone are calculated. The results show that the Coulomb stress increase value reaches 0.3 ~ 0.5barin in the depth of less than 10 km west of the trench, which is distributed in NE direction. The stress increases in the depth range of 20 km on the arc side of Luzon Island, and the region of the stress increase is in good agreement with the distribution of the earthquake.
【作者单位】：中国科学院边缘海地质重点实验室中国科学院南海海洋研究所;中国科学院大学;
【基金】：国家自然科学基金项目(41376063,41176054)
【分类号】：P736.1;P738.4
【正文快照】： 南海作为我国最大的边缘海,从全球板块构造格局的角度分析,其地处西太平洋的会聚地带,东部为太平洋板块、西部为欧亚板块、南部为印度—澳大利亚板块。从区域构造方面分析,北边为南海北部张裂边缘构造带,南边为已经停止活动的南沙海槽碰撞构造带,西边为南北向越南陆坡大型平移

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