探讨地震宏观破坏场分布的影响因素

提出震后根据仪器定位的微观震中和断层构造的关系快速确定可能的宏观震中位置,并依此使用烈度经验分布模型来进行震害快速评估。这将提高直接用微观震中位置进行震害快速评估方法的精度。通过对全国133个主要地震的微观震中与宏观震中偏离量进行统计可知。偏离量在35km范围内的占88％,其余基本都在75km范围内。这样就给出了判定宏观震中的重点区域和分析区域。详细分析南北地震带66个震例及其与断层空间分布特征的关系。以及震源机制解结果后发现,影响宏观震中偏离的因素除仪器定位本身的误差外,主要还有断层展布方向、活动规模、断层相互交接特征及震级大小等。通过对这些影响因素的分类处理分析,建立了震后室内快速判定可能的宏观震中位置的原则和步骤。以该方法为基础,通过建立包含有关因素的全国断层数据库,即可在实际的震害快速评估中得以应用。

Study on the Main Affected Factors of the Distribution of the Macro field of Earthquake

Some possible macroseismic epicentres can be given by the analysis about the relationship between the epicentre and faults.Based on those so|called macroseismic epicentres,we can use statistic distribution model of seismic intensity to estimate seismic hazard immediately after a shock.In comparison with the method by the epicentre directly,the estimating precision of this one can be increased.;According to the statistic result of the distances between macroseismic epicentres and the epicentres of 133 main earthquakes in China,the distances of 88 percent earthquakes are below 35km and those of the others are from 35km to 75km.We have chosen the circle of which the center is seismic epicentre and the radius is 35km as main analysis area,and chosen the circle of which radius in 75km as general analysis area.By study of 66 seismic examples in north|south seismic zone in China,we have known that the main effective factors on the distance between macroseismic epicentre and the epicentre are fault size,fault distribution,fault jointure type and magnitude.A practical method to identify the most possible location of macroseismic epicentre has been given in this paper.