强余震的灾害评估

极震区的烈度分布是由主震和大余震产生的。最重的地震灾区为余震区，其范围可由震级与地震区烈度的统计关系求得。在震级与震中烈度关系中，初期余震的烈度略高于主震，晚期强余震的烈度比主震的低。不同烈度对建筑物的损害程度可通过烈度与损失率曲线进行评估。强余震和后续强震的人口伤亡比主震轻。

Disaster Estimation of Strong Aftershocks

The intensity distribution in the meizoseismal region could be produced by the mainshock and great aftershocks. The aftershock region is the gravest stricken one, whose range can be deduced by statistical relatiors between seismic area and magnitude. Theintensity of the initialstage aftershocks are higher than that of mainshock and intensity of later strong aftershoks are lower than that of mainchock. The damage level of the buildings for different intensity can be evaluated according to the statistical relations curve between intensity and damage rate. The casualties from strong aftershocks and successive earthquakes are lower than that from mainshock.