Mapping Total Risk in Urban Areas

At the present level of scientific and engineering capability little can be done to prevent extreme natural events, but their effects can be alleviated through adequate planning. The first step in hazard mitigation planning is vulnerability analysis, usually presented in the form of hazard maps. Past efforts have been largely devoted to small-scale, single-hazard maps, whereas comprehensive urbanplanning requires large-scale, multi-hazard risk maps which show expected local variations in severity over small areas.In 1972, the Office of Emergency Preparedness submitted to the US Congress a comprehensive study of the types of major natural disasters experienced in the United States. This report analyzed the causes and effects of natural disasters and offered findings and potential solutions to prevent or minimize loss of life and damage to property. In their report, the Office of Emergency Preparedness discussed the need for risk maps, and commented on problems with the present standard of mapping and various authorities have pointed out weaknesses and deficiencies apparent in past examples of risk mapping designed for use in local planning. The methodology for risk mapping discussed here attempts to overcome some of these deficiencies.