余震信息在岷县漳县6.6级地震震后应急救援重灾区快速判定时作用探讨

Effects of Aftershocks on Quick Determination of Hard-hit Area for Emergency Rescue after the Minxian-Zhangxian M_S6.6 Earthquake

利用震后可以快速获取的余震信息,迅快速判定出地震重灾区的范围,为震后快速应急救援提供决策服务是十分重要的。本文利用甘肃岷县漳县6.6级地震后12小时余震分布,以1小时为单位,分时段绘制余震空间分布图,结合居民点的空间分布、发震断层走向和地形地貌条件,与实际考察得到的烈度图进行比较,初步得出以下认识:震后3小时左右余震分布集中的区域可能是破坏最严重的地区;沿余震展布方向需要考虑震区地形地貌和降雨等次生灾害因素所引起的破坏;由余震分布范围来确定重灾区时,长轴方向需要参考发震断层的走向进行调整;依据震区居民点分布密度调整重灾区位置;考虑各种致灾因素的影响,综合判定重灾区的范围。

Information used to evaluate disaster conditions shortly after an earthquake is very limit- ed. To develop fast earthquake emergency response and rescue techniques using aftershock infor- mation that can quickly be accessed, the location relationship between the spatial distribution of aftershock activity in different time periods and heavy disaster area of intensity distribution is ana- lyzed by actual investigation after an earthquake. Moreover, considering the influence factors of the seismogenic fault strike, residential area density, landform, and physiognomy in seismic are- a, the optimum time point of aftershocks statistics can reflect severe disaster areas. To quickly e- valuate the severity of disaster areas according to the distribution of aftershocks at the optimum time point with consideration of other influencing factors after earthquakes, improvements can be made in services provided for earthquake emergency rescue. It was determined that the most severe damages occur 3 h after aftershock distribution, and earthquake landform and rainfall disaster damage occur along the direction of aftershock distribu- tion. When a severe disaster area is determined by the aftershoek distribution range, adjustments of the long axis direction should be made in reference to the seismogenic fault strike; the direction of the long axis is generally consistent with seismogenie fault direction. Disaster severity is adjus-ted on the basis of settlement distribution. Therefore, comprehensive analysis of the influence of various factors causing the disaster is necessary for disaster mitigation.