with the occurrence of different geophysical events. For earthquakes, the effects of strong ground motion on low-rise, medium end high-rise buildings and the possibilities of fire following earthquake are estimated, For tropical cyclones, the wind and storm surge hazard impacts are simulated. Effects of associated phenomena caused by severe thunderstorm activity (e.g. along a squall line, tornadoes and hail) are also approximated. Specification of ,the geographical severity patterns (maximum wind speed, surge depth, ground motion) that can be expected as a result of the occurrence of a geophysical event can be attempted. To provide a means of approximating these patterns, mathematical generators have been developed. These computer-derived patterns are compared and verified with actual storm and earthquake pattenzs whenever possible. In general, they provide adequate approximations of observed conditions although each geophysical event has its own uniqueness. Nowever, there are internal consistencies and physical constraints on pattern size, shape and severity gradient among events with comparable physical characteristics. It is these pattern consistencies on which the mathematical generators are based. For tropical cyclones, the geographical severity patterns (maximum wind speed and storm surge depth) are based upon particular combinations of physf cal characteristics {storm intensity as measured by central bsrometric pressure, storm size, rate of storm movement, stage of development and so storm path). For earthquakes, the geographical pattern of effects is expressed in terms of modified Mercalli intensity. In the case of California this pattern is expressed in terms of spectral velocity or spectral acceleration by wave length category for various types of buildings based upon physical characteristics of an earthquake (Richter magnitude, depth, epicentre location, type and orientation of fault zone). These mathe- matically generated severity patterns, which are based upon currently available information in meteorology and seismology, provide a very rough first approximation of the geophysical event 
**Analysis**
The text appears to be focused on understanding and predicting the effects of natural disasters, such as earthquakes and tropical cyclones, on various aspects of society. It discusses the generation of mathematical patterns to approximate the severity of these events and their impact on different types of buildings and infrastructure. This suggests that the text is more concerned with understanding the physical and environmental aspects of these disasters rather than their economic, social, or cultural implications.

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