A version of this approach could possibly be used in developing countries in order to ident ify gaps in the information and data required for making natural risk impact assessments. It is possible that many of the basic information needs of the regional and city planner can be satis- fied with the use of current knowledge about the physical characteristics of storms and earth- quakes in the area, without waiting for a number of years for more detailed and accurate infor- mation. A computerised simulation approach has been used to provide flood loss estimates for the fifty million single-family dwellings affected by this hazard in the United States. The results pf these simulations provided a basis for the development of a joint federal government and insurance industry national flood insurance programme which is now operational. 27 IX. RISK ANALYSIS AND PHYSICAL PLANNING Disasters have major direct and indirect socio-economic effects, in addition to the physical destruction that may occur. This is even more significant in developing countries where the lag between economic development and demographic growth is already considerable. As has been said above, disasters have both immediate and long-term implications and plans formulated for disaster-prone areas should cover both these contingencies. It should also be remembered that a disastrous occurence may initiate a chain of severe hazards in addition to the direct impact damage, Risk analysis and mapping should be carried out not only to meet the requirements of physical planning but also of sound economic and social development. Maps needed for such purposes should indicate risk implications of each type of natural phenomenon and attempt to identify and guide the formulation of appropriate action programmes, development controls, land-use zoning regulations and special building codes, etc. For the respective types of hazards these should ideally be at the micro-level. It is also necessary to provide a composite risk indi- 
**Analysis**
The text primarily discusses the approach to natural risk impact assessments, specifically focusing on identifying gaps in information and data required for these assessments. It also mentions the use of computerized simulations to estimate flood loss and the development of a national flood insurance program. Additionally, the text highlights the importance of risk analysis and mapping in disaster-prone areas to inform physical planning, economic development, and social development. Based on this, it seems that the text is more focused on the intersection of natural hazards and human activities rather than a specific sector.

**Category**
Natural resources and environment, Science and technology