Notes on Natural Hazards

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When natural disasters strike, the amount of people injured/killed can be affected by the city’s structure or lack thereof Processes The physical, chemical, and biological ways in which events, such as the volcanic eruption, eathquakes, landslides and floods affect the Earth’s surface Internal processes: cause things like earthquakes and volcanic eruptions Processes we consider to be hazards result from natural forces such as the internal heating of Earth or from external energy from the sun Definitions Natural hazard A natural process and event that is a potential threat to human life and property. The process and events themselves are not a hazard but become so because of human use of the land Natural Disaster Is a hazardous event that occurs over a limited time span in a defined area. Criteria for natural disaster are: Ten or more people killed 100 or more people affected A state of emergency is declared International assistance is requested If any one of these applies, an event is considered a natural disaster Increasing trend of these Catastrophe Is a massive disaster that requires significant expenditure of money and a long time (often years) for recovery to take place The annual average loss of life has been about 80,000 Financial loss now exceeds $50 billion per year Not including social losses such as loss of employment, mental anguish and reduced productivity. Fundamental Concepts for understanding Natural Processes and Hazards Hazards are predictable from scientific evaluation Risk analysis is an important component in our understanding of the effects of hazardous processes Hazardous processes are amenable to risk analysis Estimates the probability that an event will occur and the consequences resulting from that event Defined: the product of the probability of that event occurring times the consequences should it occur
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