福建地区地震活动特征及区域应力场研究
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摘要
本文通过对福建地区地质构造背景和地震活动性背景的分析,结合2007~2009年福建地区ML4.0级以上地震的活动概况,综合认为福建地区地震活动显著增强,这可能也预示着东南沿海整体地震活动水平的抬升。从7个ML4.0级以上地震的单个震源机制解结果分析认为,古田水口水库地区的地震表现为倾滑的正断层性质,其余地震的走滑性质更为明显;且各个地震的主压应力轴方向也存在一定的差异。利用多个地震的分区综合节面解结果分析认为,近期福建地区中等强度地震活动显示出的区域应力场方向以北西向为主,在不同区域主压应力的方向有所差异:福建中北部近海地区为北西向,中北部内陆地区为北北西-南南东向;福建南部及其近海地区为近东西向。主要受到菲律宾板块向西推挤作用的影响。
Through the background analysis of geological tectonic and seismicity in Fujian area,combining with the seismicity(ML≥4.0) in Fujian area during 2007~2009,the seismicity enhanced remarkably,it also shows that the level of seismicity will be promoted in southeastern coastal areas.Analysis the result obtained from focal mechanism solution of seven earthquakes(ML≥4.0),in Gutian reservoir area is dipslip normal fault,while others are strike-slip faults.The direction of 7 compressive principal stress axes are different.The results of composite plane solution in divided zones obtained from moderate intensity seismicity in Fujian area shows that the direction of regional stress field is NW,while,the direction is different in different areas,such as,in central and north of Fujian coastal region the direction is NW,in central and north of Fujian inland area the direction is NNW and in south of Fujian coastal region the direction is EW,which may caused by the shove of Philippine plate from east to west.
Through the background analysis of geological tectonic and seismicity in Fujian area,combining with the seismicity(ML≥4.0) in Fujian area during 2007~2009,the seismicity enhanced remarkably,it also shows that the level of seismicity will be promoted in southeastern coastal areas.Analysis the result obtained from focal mechanism solution of seven earthquakes(ML≥4.0),in Gutian reservoir area is dipslip normal fault,while others are strike-slip faults.The direction of 7 compressive principal stress axes are different.The results of composite plane solution in divided zones obtained from moderate intensity seismicity in Fujian area shows that the direction of regional stress field is NW,while,the direction is different in different areas,such as,in central and north of Fujian coastal region the direction is NW,in central and north of Fujian inland area the direction is NNW and in south of Fujian coastal region the direction is EW,which may caused by the shove of Philippine plate from east to west.
引文
[1]林思诚,史藨华等.2000.福建省志[M].北京:中国社会科学出版社.1,11～29.
[2]周峥嵘,杨马陵等.2005.1970年以来东南沿海地震活动参数的定量时空差异性分析[J].华南地震,1,8～16.
[3]杨懋源,吕培苓等.1989.地震震源机制解《中国岩石圈动力学地图集》[M].北京:中国地图出版社.
[4]许忠淮,汪素云等.1989.由大量的地震资料推断的我国大陆构造应力场[J].地球物理学报,6,636～647.
[5]Snoke J A,Munsey J W,Teague A G,et al,1984,A program for focal mechanism determination by combined use of polarity and SV-P amplitude ratio data.J.Earthquake Notes,55(3),15.
[6]Snoke J A,1989,Earthquake mechanism[A].James D E,Encyclopedia of Geophysics[C].New York,Van Nostrand Reinhold Company,239～245.
[2]周峥嵘,杨马陵等.2005.1970年以来东南沿海地震活动参数的定量时空差异性分析[J].华南地震,1,8～16.
[3]杨懋源,吕培苓等.1989.地震震源机制解《中国岩石圈动力学地图集》[M].北京:中国地图出版社.
[4]许忠淮,汪素云等.1989.由大量的地震资料推断的我国大陆构造应力场[J].地球物理学报,6,636～647.
[5]Snoke J A,Munsey J W,Teague A G,et al,1984,A program for focal mechanism determination by combined use of polarity and SV-P amplitude ratio data.J.Earthquake Notes,55(3),15.
[6]Snoke J A,1989,Earthquake mechanism[A].James D E,Encyclopedia of Geophysics[C].New York,Van Nostrand Reinhold Company,239～245.
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