昆仑M_S8.1地震前青藏块体北、东缘水平运动变形的关联特征
|
摘要
青藏块体东北缘和川滇GPS监测区 1991(1993)、1999和 2 0 0 1年高精度GPS观测资料揭示 :2 0 0 1年 11月 14日昆仑MS8 1地震前 ,青藏块体北、东缘构造区域水平运动变形场动态演变具有一定的关联性特征。即 :在继承性运动总体背景下 ,临近大震发生时两区域运动强度同步减弱且变形状态发生变化。结合地质构造分析研究认为 ,昆仑MS8 1地震前 ,青藏块体边界运动变形的关联性变化与大震孕育后期大范围应力应变快速积累所形成的扰动应力场有关 ;随着块体内部大震的发生、应变能的大量释放和构造应力场的调整 ,可能会促使块体边界地带具有较高应变积累的相关构造部位 (尤其是未被历史强震破裂贯通的地带 )的应力应变的进一步积累或破裂释放。
It is revealed by GPS observation data of the northeastern margin of the Qinghai-Xizang block and the Sichuan-Yunnan area in 1991(1993),1999 and 2001 that: Before the Kunlun M S8.1 earthquake on Nov. 14 of 2001, the dynamic horizontal movement and deformation of the northern and eastern margin of Qinghai-Xizang block had connected features to some degree. That is, the deformation intensity of these two tectonic areas weakened just before the earthquake. Combined with analysis of geological tectonics, it concluded that, the connected variation of regional deformation of block boundary before the M S 8.1 earthquake inside the Qinghai-Xizang block, related to disturbance stress field caused by large-range accelerated accumulation of stress-strain when the huge earthquake was developed inside the block; with the release of strain energy of huge earthquake and adjustment of tectonic stress field inside the block, relevant tectonic position of high strain accumulation along block boundary (especially the belt which hasn't ever been linked up by fractures of historical strong earthquakes) may be stimulated accumulation of stress-strain or rupture.
It is revealed by GPS observation data of the northeastern margin of the Qinghai-Xizang block and the Sichuan-Yunnan area in 1991(1993),1999 and 2001 that: Before the Kunlun M S8.1 earthquake on Nov. 14 of 2001, the dynamic horizontal movement and deformation of the northern and eastern margin of Qinghai-Xizang block had connected features to some degree. That is, the deformation intensity of these two tectonic areas weakened just before the earthquake. Combined with analysis of geological tectonics, it concluded that, the connected variation of regional deformation of block boundary before the M S 8.1 earthquake inside the Qinghai-Xizang block, related to disturbance stress field caused by large-range accelerated accumulation of stress-strain when the huge earthquake was developed inside the block; with the release of strain energy of huge earthquake and adjustment of tectonic stress field inside the block, relevant tectonic position of high strain accumulation along block boundary (especially the belt which hasn't ever been linked up by fractures of historical strong earthquakes) may be stimulated accumulation of stress-strain or rupture.
引文
丁国瑜、卢演俦,1991,中国岩石圈动力学概论,北京:地震出版社。
范 燕、车兆宏,2003,昆仑山口西81级地震前青藏块体边界断层异常活动,地震,23(2),121～126。
虢顺民、江在森、张崇立,2000,青藏高原东北缘晚第四纪块体划分与运动态势研究,地震地质,22(3),219～230。
江在森、马宗晋、张希等,2001,青藏块体东北缘水平应变场与构造变形分析,地震地质,23(3),337～345。
江在森、张 希、祝意青等,2003,昆仑山口西MS81地震前区域构造变形背景,中国科学(D辑),33(增刊)。
王绍晋、秦嘉政、关蕾等,2003,云南强震活动的多层次动力源分析,地震研究,26(2),142～150。
张 希、江在森,2001,考虑区域构造特征的最小二乘配置方法初步研究,中国地震,17(4),403～407。
范 燕、车兆宏,2003,昆仑山口西81级地震前青藏块体边界断层异常活动,地震,23(2),121～126。
虢顺民、江在森、张崇立,2000,青藏高原东北缘晚第四纪块体划分与运动态势研究,地震地质,22(3),219～230。
江在森、马宗晋、张希等,2001,青藏块体东北缘水平应变场与构造变形分析,地震地质,23(3),337～345。
江在森、张 希、祝意青等,2003,昆仑山口西MS81地震前区域构造变形背景,中国科学(D辑),33(增刊)。
王绍晋、秦嘉政、关蕾等,2003,云南强震活动的多层次动力源分析,地震研究,26(2),142～150。
张 希、江在森,2001,考虑区域构造特征的最小二乘配置方法初步研究,中国地震,17(4),403～407。
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心