| 张渤带陆地段现代构造应力场的非均匀特征 |
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| 引用本文： | 张红艳,谢富仁,崔效锋,李瑞莎.张渤带陆地段现代构造应力场的非均匀特征[J].中国地震,2009,25(3). |
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| 作者姓名： | 张红艳 谢富仁 崔效锋 李瑞莎 |
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| 作者单位： | 中国地震局地壳应力研究所,北京市海淀区安宁庄路1号,100085 |
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| 基金项目： | 中央级公益性科研院所基本科研业务专项 |
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| 摘 要： | 依据活动构造展布及震中分布等情况,将张渤带(张家口-渤海断裂带)陆地段及邻近地区划分为6个应力区,利用格点尝试法计算了1967～2006年间这6个分区内的529个震源机制解.结果显示,6个分区的应力结构较为一致,均为走滑型应力结构;但在应力方向上有明显不同,其应力主轴方向有由西北端的NEE向至东南端的近EW向呈顺时针旋转的趋势.此外,以1976年唐山地震与1998年张北地震为时间界限,计算了张渤带陆地段3个构造交汇段(即张北-怀来段、南口-三河段、天津-塘沽段,简称西段、中段、东段)上的地震震源机制解及各构造段在不同时段的平均主应力轴分布,得到了应力场随时间的变化特征.其中,西段与中段的构造应力场变化复杂,其应力主轴方向在唐山地震后经调整已基本回复至唐山地震前的状态;而东段的平均应力主轴呈顺时针旋转,目前仍为近EW向.张渤带陆地段现代构造应力场的时空非均匀变化特征可能与周边块体的相互作用及两次中强地震(唐山地震与张北地震)有关.
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| 关 键 词： | 张渤带 震源机制解 构造应力场 非均匀性 |
Research on Heterogeneity of the Present Tectonic Stress Field at the Overland Part of the Zhangjiakou-Bohai Fault Zone |
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| Zhang Hongyan,Xie Furen,Cui Xiaofeng,Li Ruisha.Research on Heterogeneity of the Present Tectonic Stress Field at the Overland Part of the Zhangjiakou-Bohai Fault Zone[J].Earthquake Research in China,2009,25(3). |
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| Authors: | Zhang Hongyan Xie Furen Cui Xiaofeng Li Ruisha |
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| Abstract: | According to the distribution of active tectonic and earthquake epicenters, the Zhangjiakou-Bohai Fault Zone and its adjacent areas are divided into six stress districts. We use the Grid Test Method to calculate more than 500 earthquake focal mechanism solutions of these 6 districts in the period of 1977 ~ 2006. The calculated result indicates that the stress regimes of these 6 stress districts are identical and they are all of strike slip. However, there are some changes in the orientations of tectonic stress fields. On the whole, the orientation of principal stress axes is in NEE-nearly EW direction from northwest to southeast; it shows a trend of clockwise rotation. In addition, taking the Tangshan earthquake and the Zhangbei earthquake as time bound, we calculate the focal mechanism solutions of 3 tectonic merging parts (they are west part, middle part and east part respectively) in the Zhangjiakou-Bohai Fault Zone in 3 different time-intervals, and we get the time-varying characteristics of the orientation of the present tectonic stress field. The state of tectonic stress field is complex in west and middle part, the orientation of principal stress axes in both parts seems to return to the state before the Tangshan earthquake by adjusting for several years; but the orientation of principal stress axis in the east part is still in nearly EW direction at present; it does not return to the state before the Tangshan earthquake and it shows a clockwise rotation. The temporal and spatial heterogeneity of the present tectonic stress field at the overland part of the Zhangjiakou-Bohai Fault Zone may have a relation to the interaction of peripheral blocks and two moderately strong earthquakes. |
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| Keywords: | Zhangjiakou-Bohai Fault Zone Focal mechanism solution Tectonic stress field Heterogeneity |
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