攀枝花6.1级地震前南山地震台的形变异常分析
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摘要
2008年8月30日的攀枝花仁和—凉山州会理间6.1级地震前,距离最近的攀枝花南山定点形变台多套仪器监测到了明显的异常变化。本文对此次6.1级地震前的多套形变仪器记录异常作了总结研究,各套仪器监测在出现中期异常的同时,又存在短临异常。结果表明:南山地震台石英摆仪观测NS向分量存在趋势变化偏小异常的同时,又存在短期突变加速异常;长水管仪的异常变化表现为加速和转向变化;石英伸缩仪NS向分量的异常变化在震前两天出现,表现为原始记录曲线、整点值的畸变。结合历史震例总结显示:攀枝花南山台各套形变监测短临异常的开始或结束时间对台站周边未来地震的时间有一定指示意义,即异常开始后一至两个月内,在监测台站周边地区可能发生6级以上地震;各监测分量方向异常变化对台站周边未来地震可能的方位也有一定的指示意义;异常的变化幅度与未来地震震级关系不明显。
An M6.1 earthquake on 30 August 2008 occurred and its epicenter is between Renhe District and Huili County,Panzhihua City.Before this earthquake,the possible earthquake precursor anomalies were monitored by the deformation observation instrument installed in the Nanshan Seismic Station where is near the epicenter of this event.We analyze the observation data of these instruments installed in Nanshan Seismic Station and found that possible earthquake precursory anomalies are listed as following: 1 the instrument's zero drift rate got smaller than before and the fluctuation range got bigger in short period;2 The ground tilt change rates got bigger;the north-south direction strain values show a fluctuate beyond the normal limitation.According to the historical earthquake cases,same change character just as before of observation data means that an Ms6.0 earthquake might happen and it can be considered as an index for earthquake prediction within one or two months later in areas surround Seismic Station.
An M6.1 earthquake on 30 August 2008 occurred and its epicenter is between Renhe District and Huili County,Panzhihua City.Before this earthquake,the possible earthquake precursor anomalies were monitored by the deformation observation instrument installed in the Nanshan Seismic Station where is near the epicenter of this event.We analyze the observation data of these instruments installed in Nanshan Seismic Station and found that possible earthquake precursory anomalies are listed as following: 1 the instrument's zero drift rate got smaller than before and the fluctuation range got bigger in short period;2 The ground tilt change rates got bigger;the north-south direction strain values show a fluctuate beyond the normal limitation.According to the historical earthquake cases,same change character just as before of observation data means that an Ms6.0 earthquake might happen and it can be considered as an index for earthquake prediction within one or two months later in areas surround Seismic Station.
引文
[1]国家地震局预测预防司.地壳形变分析预报方法[M].北京:地震出版社,1998.
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[3]李兴坚,张立光,等.山丹—民乐6.1和5.8级地震短期异常特征[J].高原地震,2004,16(3):60-65.
[2]曹喜,张占斌,等.嘉峪关断层气氡对祁连山西段中强地震的异常特征分析[J].地震地磁观测与研究,2008,29(1):50-53.
[3]李兴坚,张立光,等.山丹—民乐6.1和5.8级地震短期异常特征[J].高原地震,2004,16(3):60-65.
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