1995年云南孟连西7.3级地震前震序列特征及其与主震的关系
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摘要
在分析 1995年云南孟连西 7 3级地震的前震序列时 ,发现跟踪最大前震6 2级的余震序列中 ,有一组较大震级的地震呈现出随时间的增长不断线性递增的特点 ,这种特点在云南其他震例中也曾多次出现过。利用修正的大森公式n(t) =k/ (t +c) p 拟合该序列 ,在获得的参数重新构造的频度 -线性化时间坐标中 ,这一组地震显示出与海城前震序列随时间变化震级出现非线性增强的共同特征。采用表征物质加速应变而失稳的方程d(∑M0 1/2 ) /dt=c/ (tm-t) n ,对孟连西前震序列多方面进行跟踪定量分析 ,预测主震的发生时间平均比实发时间仅推迟 2 6min ,震级相差 0 17级
In analysis of the foreshock sequence for the M 7 3 west Menglian earthquake in 1995 in Yunnan,it is found that a group of events with relatively large magnitude in the aftershock sequence following the maximum foreshock with M 6 2 has the feature that their magnitudes increased progressively and linearly with growth of time,which has been found many times in a lot of earthquake examples in Yunnan.In the coordinate of frequency-linearization rebuilt by the aftershock sequence according to the revised Ohmori Fusakichi's formula, n(t)=k/(t+c) p ,the group of event showed the feature in common that magnitudes of Haicheng foreshock sequence increased non-linearly with growth of time.Based on quantitative analysis of the west Menglian foreshock sequence by tracing the sequence from many aspects and using the equation d(∑ M 1/2 0)/d t=c/(t m- t ) n expressed lossing stability of mass due to acceleration and strain,it is obtained that predicted average occurrence time of the main shock is later only 26 minutes than practical occurrence time,and the difference magnitudes between predicted and practical is only 0 17.
In analysis of the foreshock sequence for the M 7 3 west Menglian earthquake in 1995 in Yunnan,it is found that a group of events with relatively large magnitude in the aftershock sequence following the maximum foreshock with M 6 2 has the feature that their magnitudes increased progressively and linearly with growth of time,which has been found many times in a lot of earthquake examples in Yunnan.In the coordinate of frequency-linearization rebuilt by the aftershock sequence according to the revised Ohmori Fusakichi's formula, n(t)=k/(t+c) p ,the group of event showed the feature in common that magnitudes of Haicheng foreshock sequence increased non-linearly with growth of time.Based on quantitative analysis of the west Menglian foreshock sequence by tracing the sequence from many aspects and using the equation d(∑ M 1/2 0)/d t=c/(t m- t ) n expressed lossing stability of mass due to acceleration and strain,it is obtained that predicted average occurrence time of the main shock is later only 26 minutes than practical occurrence time,and the difference magnitudes between predicted and practical is only 0 17.
引文
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2 吴开统 ,岳明生 ,武宦英 ,等 海城地震序列的特征 地球物理学报 ,1976 ,19(2 ) :95～ 10 9
3 许绍燮 ,王碧泉 ,章光月 ,等 海城地震前震系列与震群———兼论前震系列在地震预报中的一种功能 地震学报 ,1981,3 (1) :1～ 10
4 章光月 ,王碧泉 ,许绍燮 ,等 1975 . 2 .
4.海城地震 (M =7 3)的前震系列 地震学报 ,1983 ,5 (1) :1～ 14
5 左兆荣 ,吴建平 ,巫志玲 新丰江水库 6 1级地震前震序列分析 华南地震 ,1995 ,15 (1) :2 1～ 2 9
6 左兆荣 ,吴建平 ,巫志玲 196 6年邢台Ms7 2级地震的前震序列分析 华北地震科学 ,1995 ,13 (2 ) :7～ 15
7 左兆荣 ,吴建平 ,巫志玲 1975年辽宁海城Ms7 3级地震的前震序列分析 地震学报 ,1995 ,17(4 ) :493～ 498
8 SaitoM .Forecastingtimeofslopefailurebytertiarycreep ,Proc ,7th ,Internat,Conf,onSailMechanicsandFoundationEngineer ing . 196 9,2 :6 77～ 6 83
9 OgataY .EstimationoftheparametersinthemodifiedOmoriformulaforaftershockfrequencybythemaximumlikelihoodprocedure .J .Phys.Earth .,1983,31:115～ 12 4
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