中国西部断层形变趋势异常特征与地震活动关系研究
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摘要
运用地壳形变趋势累积率DC 值对中国西部跨断层形变的空间分布特点进行了研究 ,建立了断层活动引起的形变累积的区域图像并对其孕震意义进行了讨论。综合分析了断层形变的时域演化类型及 1995～ 1996年前后断层形变出现大范围异常的变化特点 ,明确提出 :1995～ 1996年是 90年代以来中国西部断层网络活动的转折点 ,它与中国西部地震活动主体区的转换 ,亦即青藏块体及周边构造应力场的强、弱阶段交替与作用区间的变化密切相关 ,对1996年中国西部地震活动整体格局的改变具有中短期预兆意义。在此基础上 ,对其力学机制及块体运动背景进行了初步探讨。认为 1988～ 1996年北东向 6级地震条带和 1997～ 1999年北西向 5级地震条带的形成 ,从力学原理上证明中国西部目前处于南北向应力相对减弱 ,东西向应力相对增强并起主导作用的状态。
The space distribution features of across\|fault deformation in West China have been studied by deformation trend accumulation rate D\-c .The region patterns of D\-c are set up and its seismogenic relation has been discusssed.The time\|domain evolution types and abnormal characteristic of fault deformation in large areas during 1995～1996.The main point is obviously put forward:The period of 1995～1996 is the turning point of fault activity in West China since 1990.It is closely corresponded with conversion of main seismicity areas,and the stage alternation of teconic stress field strength and its action regions in and around Qinghai\|Xizang block.This anomaly predicted the pattern changes of seismicity in West China in 1996.The mechanism and block movement background have been primarily discussed.
The space distribution features of across\|fault deformation in West China have been studied by deformation trend accumulation rate D\-c .The region patterns of D\-c are set up and its seismogenic relation has been discusssed.The time\|domain evolution types and abnormal characteristic of fault deformation in large areas during 1995～1996.The main point is obviously put forward:The period of 1995～1996 is the turning point of fault activity in West China since 1990.It is closely corresponded with conversion of main seismicity areas,and the stage alternation of teconic stress field strength and its action regions in and around Qinghai\|Xizang block.This anomaly predicted the pattern changes of seismicity in West China in 1996.The mechanism and block movement background have been primarily discussed.
引文
陈 兵、赵振才、祝意青 ,1998,祁连山 -海原断裂带断层形变异常特征量研究 ,内陆地震 ,12 (3) ,2 2 2～ 2 2 7。
陈 兵、江在森、胡 斌 ,1998,断层形变数字特征与演化研究———形变趋势累积率DC,中国地震学会第七次学术大会论文摘要集 ,北京 :地震出版社 ,10 1。
赵振才、陈 兵 ,1996 ,青藏块体北缘跨断层测量资料宏观分析 ,中国地震 ,12 (4) ,35 8～ 36 5。
曾秋生 ,1990 ,中国地壳应力状态 ,北京 :地震出版社 ,6 2～ 6 4。
陈 兵、江在森、胡 斌 ,1998,断层形变数字特征与演化研究———形变趋势累积率DC,中国地震学会第七次学术大会论文摘要集 ,北京 :地震出版社 ,10 1。
赵振才、陈 兵 ,1996 ,青藏块体北缘跨断层测量资料宏观分析 ,中国地震 ,12 (4) ,35 8～ 36 5。
曾秋生 ,1990 ,中国地壳应力状态 ,北京 :地震出版社 ,6 2～ 6 4。
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