汶川大地震宏观震中问题的讨论

Discussion on Macro-epicenter of Wenchuan Earthquake

采用大地震诱发崩塌滑坡特点与地面破坏程度相结合,以及极震区几何中心方法,定性判定了汶川大地震的宏观震中位置。判定结果是汶川大地震应该有2个宏观震中,一是映秀镇牛圈沟为映秀极震区宏观震中,坐标位置:31.045 6°N,103.455 6°E;二是北川老县城为北川极震区宏观震中,坐标位置:31.863 7°N,104.361 0°E。两种判定方法相比,前者更符合山区特殊地质地貌环境下的地震破坏规律。

The macro-epicenter of Wenchuan earthquake is qualitatively determined by the method of combining the characteristics of earthquake-induced landslides and collapses with ground destructiveness,and the geometric center of the extreme seismic zone.Results show that Wenchuan earthquake should have two macro-epicenters.One is Niujuan canyon in Yingxiu extreme seismic region with coordinates as 31.045 6°N,103.455 6°E,and the other is Beichuan county in Beichuan extreme seismic zone with coordinates as 31.863 7°N,104.361 0°E.Two judging methods are compared,and the former is proved to be more in line with the law of earthquake destruction in the mountainous areas with special geological and geomorphological environment.