Study and Exposure to Natural's Disaster for World Cities

Disasters are a mixture of threats, threat factors and inadequate capability or risk-reduction measures. Disasters, particularly those that appear primarily to be caused by natural hazards, are not the greatest threat to mankind. A hazard becomes a disaster when it coincides with a vulnerable situation, when societies or communities cannot cope with its own resources and capacities. A hazard is a physical event, phenomenon or human activity that can cause loss of life or injury, damage to property, social and economic disruption or degradation to the environment. Hazards have various origins: natural (geological, hydro, meteorological, and biological) or human (environmental or technological) actions. Risk is the probability of adverse effects or predicted losses (deaths, accidents, properties, livelihoods, disrupted economic activity or damaged environment) arising from interactions between natural or man-made hazards and vulnerable populations. Climate change will create new hazards such as the melting of glaciers, sea level rise and extreme weather in proportions never seen before. A natural disaster is defined as a natural event that overwhelms local resources, and threatens the community's function and safety. Disasters are hard to plan and anticipate since they are innately different from common emergencies.