| 汶川MS8.0地震前后龙门山及其 邻区构造应力场时空分布特征 |
| |
| 引用本文： | 虎雄林,王强,解朝娣.汶川MS8.0地震前后龙门山及其 邻区构造应力场时空分布特征[J].地震学报,2015,37(5):747-761. |
| |
| 作者姓名： | 虎雄林 王强 解朝娣 |
| |
| 作者单位： | 1.中国昆明 650224 云南省地震局 |
| |
| 基金项目： | 国家自然科学基金41004021国家自然科学基金41090292国家自然科学基金41104036 |
| |
| 摘 要： | 基于2000年7月—2009年6 月龙门山及其邻区的震源机制解资料， 采用Gephart & Forsyth方法， 反演得到了汶川地震前后该地区构造应力主方向的空间分布. 结果显示: 沿鲜水河断裂带及其北部地区， 构造应力场变化显著， 区域构造应力的最大主应力方位由NNW变为NW， 断层错动类型由正断型兼走滑型变为走滑型； 沿龙门山断裂带的构造应力最大主应力方向仍然为近EW和NE向， 但其EW向范围在向NE方向扩张， 其南部汶川地震震中附近异常带范围在收缩. 另一方面， 对上述时间段龙门山及其邻区不同时段构造应力场的反演结果表明， 其构造应力场的特征参数(包括R值、 应力洛德参数μ′以及3个主应力的方位角和仰角等)均从第13时窗开始出现显著变化， 这表明第13时窗(2006年12月—2007年1月)是一个构造应力显著变化的特征窗口. 在该时窗内， 地震能量积累达到一个临界状态， 是汶川MS8.0地震发生的时间节点.
|
| 关 键 词： | 汶川地震 龙门山 构造应力场 |
| 收稿时间： | 2015-01-17 |
Spatio-temporaI distribution of tectonic stress fieId in Longmenshan and its adjacent regions before and after Wenchuan MS8.0 earthquake |
| |
| Affiliation: | 1.Earthquake Administration of Yunnan Province， Kunming 650224， China2.Department of Geophysics， Yunnan University， Kunming 650091， China |
| |
| Abstract: | Based on the focal mechanism solutions for Longmenshan and its adjacent regions from July 2000 to June 2009, the spatial distribution of the main direction of tectonic stress fields are retrieved in the regions before and after the Wenchuan MS8.0 earthquake by using the Gephart & Forsyth method. The results show that the tectonic stress fields change significantly along Xianshuihe fault zone and the region to the north, and that the maximum principal stress direction of the regional tectonic stress shifts from NNW to NW, while the faulting changes from combined normal fault and strike-slip to strike-slip only. Significant changes can also be observed in the tectonic stress field along the Longmenshan fault zone. Although the maximum principal stress direction still approximates to the east-west and north-east, its scope is expanding towards the east-north, and the abnormal belt near the epicenter of Wenchuan earthquake shrinks. On the other hand, the retrieval results of the tectonic stress fields in Longmenshan and its adjacent regions during different periods from July 2000 to June 2009 show that the characteristic parameters of tectonic stress fields, including the R value, Lode parameter μ′, azimuths and elevation angles of three principal stresses, begin to change significantly since the thirteenth window, suggesting that the thirteenth window (December 2006 to January 2007) is a characteristic window with significant changes in the tectonic stress. In the thirteenth window, the seismic energy is accumulated to a critical state, signaling the time node for the occurrence of Wenchuan MS8.0 earthquake. |
| |
| Keywords: | |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
| 点击此处可从《地震学报》浏览原始摘要信息 |
|
点击此处可从《地震学报》下载全文 |
|
