摘要
通过对华北北部11次Ms≥5.0地震前2年至震后1年震源区(△≤150km)附近中小地震主压应力轴相对背景场的变化研究结果表明,Ms≥5.0地震前9～1个月左右,震源区附近中小地震主压应力轴往往出现45°～90°左右的转向变化,或主压应力轴出现仰角增大,且增大幅度大于45°的异常变化,这种变化一般在震后几个月至1年左右结束。
The variation of the major pressure stress axis of medium-small earthquakes in 2 years before 11 earthquakes with Ms ≥5.0 and 1 year after 11 earthquakes with Ms≥5.0 nearby the focal region in the north area of North China compared with the background stress field was analyzed in this paper.The result showed that the major pressure stress axis appeared the deflection of 40°-90°, or the dip angle increased over 45°. This variation ended in 1 year after the main event.
出处
《东北地震研究》
2008年第1期8-13,共6页
Seismological Research of Northeast China
关键词
华北北部
中小地震
主压应力轴
P轴转向
标志地震
the north area of North China
medium-small earthquake
major pressure stress axis
deflection of P axis
mark event
