21世纪地震灾害的一些新特点

灾害定量化是地球科学、工程科学和社会经济科学的交叉领域。人口城市化是全球的发展趋势，特别在第三世界人口城市化的趋势越来越显著。和农村发生突发灾害农民可以很容易地进行自救和互救不同，城市居民对供水、供电、煤气、暖气、通讯和交通等基础设施有很大的依赖性，现代城市在抗御自然灾害方面，比过去任何时候都显得更加脆弱。通过统计，我们发现在灾害损失 L和表征社会财富的GDP之间存在着经验关系：L＝ a＋ b×GDP＋ c×GDP 2其中 a，b，c为正的常数。关系式表明，自然灾害造成的灾害增长要比GDP的增长要快。

NEW FEATURE OF EARTHOUAKE DISASTER IN 21st CENTURY

Quantification of natural disaster is a new research area between the earth science, engineering science and the socio-economical science. The urbanization is an worldwide trend. This trend is especially pronounced in the countries of the Third World, where the number of cities over a million inhabitants has increases sixfold in the past 50 years. City people are more dependent on the infrastructure, i.e. the supply of water, electricity, gas, heating, telecommunications and transport connections than the more self-reliant rural population, which is more accustomed to helping one another in emergencies. Numerous natural catastrophes of recent years have shown quite emphatically how vulnerable the infrastructures of major cities are to minor breakdowns and how acute shortages in supply can develop within a short time. Our statistics showed that there is a empirical relation between the economic loss caused by natural hazards (in million US$) and the social wealth expressed by GDP(in million US$) is:Loss cause by natural hazards=a+b GDP+c GDP~(2) where a, b, and c are positive constants, it means that the losses increase faster than the increase of GDP.