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| 1996年川滇地区发生的一次应力转向事件 | |
| 引用本文： | 王凯英,马瑾,顾国华,刁桂苓.1996年川滇地区发生的一次应力转向事件[J].地学前缘,2003,10(Z1):233-239. |
| 作者姓名： | 王凯英 马瑾 顾国华 刁桂苓 |
| 作者单位： | 1. 中国地震局,地质研究所,地震动力学实验室,北京,100029 2. 中国地震局,分析预报中心,北京,100036 3. 河北省地震局,河北,石家庄,050021 |
| 基金项目： | 国家自然科学基金，国家重点基础研究发展计划(973计划)，40072067，G199804070401，， |
| 摘 要： | 1994— 2 0 0 0年间川滇地区小震震源机制解的分析结果显示 ,川滇地区的应力场存在以丽江—小金河断裂为界的分区特征 :丽江—小金河断裂以北地区 (北区 )存在双重力源应力场 ,而南部地区(南区 )应力方向单一 ;并发现北区在 1996年前后发生过一次应力场转向事件 ,转变前后的应力主轴方位分别对应双重力源的两个方向 ,反映了双重力源在北区随时间的相互作用。南区应力场较为平稳 ,在此期间几乎无变化。GPS测量结果显示 ,1998— 2 0 0 0年丽江—小金河断裂带的活动方式与新构造运动时期的累积位移相反 ,也表明了川滇北部地区应力场发生了转变。 |
| 关 键 词： | 震源机制 GPS 应力方向 活动断裂 |
| 文章编号： | 1005-2321(2003)S0-0233-07 |
| 修稿时间： | 2003年4月27日 |
ROTATION OF STRESS AXIS IN SICHUAN-YUNNAN REGION IN 1996 |
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| WANG Kai-ying ,MA Jin ,GU Guo-hua ,DIAO Gui-ling.ROTATION OF STRESS AXIS IN SICHUAN-YUNNAN REGION IN 1996[J].Earth Science Frontiers,2003,10(Z1):233-239. | |
| Authors: | WANG Kai-ying MA Jin GU Guo-hua DIAO Gui-ling |
| Institution: | WANG Kai-ying 1,MA Jin 1,GU Guo-hua 2,DIAO Gui-ling 3 |
| Abstract: | The area studied is the western region of Sichuan and Yunnan provinces, which may be divided into sub-regions based on the distribution of strong earthquakes, active tectonics and geologic data. Temporal-spatial characteristics of stress orientation in the area are studied in this paper. More than 1 000 focal mechanism solutions with magnitude less than 5 from 1994 to 2000 and GPS data from 1997 to 2000 are analyzed. The spatial distribution of average P axis orientations and their temporal variation in these sub-regions indicate that the stress fields of sub-regions divided by the Lijiang-Xiaojinhe fault are different. The stress field in the northern part is characterized by two dominant and coexisting directions (northeastward and northwestward); meanwhile, the stress field in the southern part is relatively simple, and directions of P axis of its two sub-regions are nearly SN-directed. Analysis of the data with time shows that the orientation of P axis in the northern part rotated from northwest to northeast around 1996. In contrary, in the two sub-regions to the south of the Lijiang-Xiaojinhe fault there was almost no difference of P axis directions in the same periods. It means that an event with rotation of stress-orientation occurred in the three subregions to the north of the Lijiang-Xiaojinhe fault in 1996. GPS data in the area and geodetic leveling data across the Xianshuihe fault and short baselines across the Zemuhe fault, more or less, provide circumstantial evidence for this rotation of stress orientation. Dynamic condition in the area studied for this rotation is discussed. |
| Keywords: | focal mechanism GPS stress orientation active fault |
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