张北6.2级地震的连续形变前兆异常时空特征
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摘要
采用首都圈连续形变观测网内倾斜及应变的观测资料 ,对张北地震的前兆异常及其特征进行了分析研究 ,得到如下结果 :震前 1年半到两年 (即 1 996年 )在这一地区存在较大区域的连续形变异常 ;在这种中长异常背景的基础上 ,倾斜、应变观测结果再次出现新一轮异常 ,并且新的异常在观测地点和时间上一致 ,异常点相对于中长期时的空间范围缩小 ,向震中区集中 (约2 0 0 km范围内 )。新一轮异常从其中最早的异常开始到地震发生在 1年以内 ,并且随发震时间的逼近 ,不同观测项目和不同观测方向的各种参量的异常表现更为一致和显著 ,其中以离震中最近的张家口的异常变化最为突出
The precursory anomalies and its characteristics of the Zhangbei earthquake are analyzed and researched using the observed data of the tilt and strain tides in the capital area. The results show that from one year and half to two years before the earthquake, there were widely anomalies of the deformalion in the area. On the basis of the background of the long-mid anomalies, a new round of anomalies were observed again. These new ones were coincident in place and starting time, and the abnormal points were reduced and concentrated into the epicenter (in a ramge of about 200 km). The duration of the new round of abnormalities was less than 1 year before the earthquake, the anomalies of various parameters in different observation items and different directions were more consistent and obvious when the earthquake approaching. The abnormal changes of observation at Zhangjakou which is nearest to the epicenter were the biggest.
The precursory anomalies and its characteristics of the Zhangbei earthquake are analyzed and researched using the observed data of the tilt and strain tides in the capital area. The results show that from one year and half to two years before the earthquake, there were widely anomalies of the deformalion in the area. On the basis of the background of the long-mid anomalies, a new round of anomalies were observed again. These new ones were coincident in place and starting time, and the abnormal points were reduced and concentrated into the epicenter (in a ramge of about 200 km). The duration of the new round of abnormalities was less than 1 year before the earthquake, the anomalies of various parameters in different observation items and different directions were more consistent and obvious when the earthquake approaching. The abnormal changes of observation at Zhangjakou which is nearest to the epicenter were the biggest.
引文
1 蒋骏 ,张雁滨 .潮汐剪切应变观测与孕震区剪切应变强度因子 .地壳形变与地震 ,1 993,1 3(增刊 2 ) ,2 3～30 .
2 蒋骏 ,张雁滨 .潮汐面应变的综合观测与地震扩容前兆 .地壳形变与地震 ,1 993,1 3(增刊 2 ) :31～ 36.
3 蒋骏 ,张雁滨 .潮汐线应变组合观测的物理力学实质及其调和分析 .地球物理学报 ,1 994,37(增刊 2 ) :2 0 4～ 2 1 2 .
4 张雁滨、蒋骏 ,等 .连续形变观测的综合分析及丽江地震前兆异常特征 .地壳形变与地震 ,1 997,1 7(增刊 ) :1 1 7～ 1 2 3.
5 张国民 ,张永仙 ,石耀霖 .震源过程的数值模拟和短临前兆特征的成因 .中国地震 ,1 995,1 1 (4) :32 7～ 340 .
6 吴翼麟 ,周克昌 .孕震区形变前兆的配套和有序 .地壳形变与地震 ,1 993,1 3(增刊 2 ) .
7 Beaumont C,Berger J. Modification oftheearth tide tiltand strain by dilatancy,Geophs. J.R.astr.Soc.1 997,39,1 1 1～ 1 2 1 .
8 Kirsch R,Zschou J. The Influence of a dilatantregion in theearth'scruston the earth tide and strains. JGeophys,1 986,59:1 57～ 1 63
2 蒋骏 ,张雁滨 .潮汐面应变的综合观测与地震扩容前兆 .地壳形变与地震 ,1 993,1 3(增刊 2 ) :31～ 36.
3 蒋骏 ,张雁滨 .潮汐线应变组合观测的物理力学实质及其调和分析 .地球物理学报 ,1 994,37(增刊 2 ) :2 0 4～ 2 1 2 .
4 张雁滨、蒋骏 ,等 .连续形变观测的综合分析及丽江地震前兆异常特征 .地壳形变与地震 ,1 997,1 7(增刊 ) :1 1 7～ 1 2 3.
5 张国民 ,张永仙 ,石耀霖 .震源过程的数值模拟和短临前兆特征的成因 .中国地震 ,1 995,1 1 (4) :32 7～ 340 .
6 吴翼麟 ,周克昌 .孕震区形变前兆的配套和有序 .地壳形变与地震 ,1 993,1 3(增刊 2 ) .
7 Beaumont C,Berger J. Modification oftheearth tide tiltand strain by dilatancy,Geophs. J.R.astr.Soc.1 997,39,1 1 1～ 1 2 1 .
8 Kirsch R,Zschou J. The Influence of a dilatantregion in theearth'scruston the earth tide and strains. JGeophys,1 986,59:1 57～ 1 63
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