1996年包头6.4级地震的地壳应变特征
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摘要
根据GPS观测资料求出的水平地应变和由跨断层垂直形变计算出的速率强度累积率,研究了包头-大同地区1992～1995年、1995～1996年和1996～1999年的各时期的应变特征,并对包头6.4级(1996年5月3)地震前后的地应变进行对比,认为以压应变为主导的高值区可能是未来强震孕育的地区.面应变、主压应变、剪应变和趋势累积率同时较高的地区,强震危险性较大.一般低应变区和张应变为主导的地区,孕育强震的可能性小,属于比较稳定的地区.1992～1999年包头-大同地区的GPS水平应变的演变,反映了1996～1998年地震幕的孕育发展及结束的全过程.以压应变为主的高应变区和应变梯度带可作为未来强震危险区的判定标志之一.
Based on the horizontal crustal strain derived from GPS data and the rate accumulation intensity calculated from across-fault vertical deformation, the strain characteristics in the periods of 1992~1995, 1995~1996 and 1996~1999 in Baotou-Datong area is studied in the paper. From the comparison between the crustal strains before and after the M=6.4 Baotou earthquake occurred on May 3, 1996, it is considered that the high-magnitude area with predominant compressive strain might be the seismogenic zone for a coming strong earthquake. The area with the simultaneous higher surface strain, principal compressive strain, shear strain and tendency accumulation might be the place with higher risk of strong earthquakes. Generally, the area with low strain and predominant tensile strain might have a small possibility for strong earthquake development, which belongs to a stable area. The evolution of horizontal strain obtained from GPS measurements carried out in Baotou-Datong area in the period of 1992～1999 reflects the total developing and ending processes of the seismic episode from 1996 to 1998. The area with high and predominant compressive strain and the strain gradient zone can be considered as one of the indicators for determining the strong earthquake risk area in the future.
Based on the horizontal crustal strain derived from GPS data and the rate accumulation intensity calculated from across-fault vertical deformation, the strain characteristics in the periods of 1992~1995, 1995~1996 and 1996~1999 in Baotou-Datong area is studied in the paper. From the comparison between the crustal strains before and after the M=6.4 Baotou earthquake occurred on May 3, 1996, it is considered that the high-magnitude area with predominant compressive strain might be the seismogenic zone for a coming strong earthquake. The area with the simultaneous higher surface strain, principal compressive strain, shear strain and tendency accumulation might be the place with higher risk of strong earthquakes. Generally, the area with low strain and predominant tensile strain might have a small possibility for strong earthquake development, which belongs to a stable area. The evolution of horizontal strain obtained from GPS measurements carried out in Baotou-Datong area in the period of 1992～1999 reflects the total developing and ending processes of the seismic episode from 1996 to 1998. The area with high and predominant compressive strain and the strain gradient zone can be considered as one of the indicators for determining the strong earthquake risk area in the future.
引文
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李延兴,胡新康,赵承坤,等.1998.GPS跟踪站观测的初步结果所揭示的板内及板缘地壳水平运动[J].地壳形变与地震,18(2):28～34
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GuoLiangqian.2000.Preliminary study on the horizontal crustal deformation in chinese continent[J].EarthquakeResearch inChina,14(4):312～322
LiYanxing,HuangCheng,HuxinXinkang,et al.2001.Model of rigid and elastic-plastic motion in intraplate blocks and strain status of principal blocks inChinese mainland[J].ActaSeismologicaSinica,14(6):603～610
黄立人,马青,朱文耀,等.1996.高精度GPS测量得到的中国西南地区构造块体运动模型的初步结果[A].见:李延兴主编.GPS技术研究新进展[C].天津:天津科学技术出版社,232～229
李延兴,胡新康,赵承坤,等.1998.GPS跟踪站观测的初步结果所揭示的板内及板缘地壳水平运动[J].地壳形变与地震,18(2):28～34
陆远忠,吴云,王伟,等.2001.地震中短期预报的动态图象方法[M].北京:地震出版社,26～28
俞鸿年,芦华复.1986.构造地质学原理[M].北京:地质出版社,96～99
BillingsM P著.1956;张炳熹译.1973.构造地质学[M].北京:地质出版社,29～31
GuoLiangqian.2000.Preliminary study on the horizontal crustal deformation in chinese continent[J].EarthquakeResearch inChina,14(4):312～322
LiYanxing,HuangCheng,HuxinXinkang,et al.2001.Model of rigid and elastic-plastic motion in intraplate blocks and strain status of principal blocks inChinese mainland[J].ActaSeismologicaSinica,14(6):603～610
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