In a single year, about 17 earthquakes of the same magnitude as the haiti earthquake occur. Natural hazards result in the loss of 150 000 lives yearly; financial loss exceeds billion a year. All processes that lead to natural disasters are powered by energy; which is derived from three sources. Earth"s internal heat, which produces slow convection in the mantle (associated processes are earthquakes and volcanic eruptions) The sun, which warms the atmosphere and surface, produces winds and evaporates water (the evaporation of water drives the hydrologic cycle) Gravitational attraction; due to gravity, everything is slowly pulled downward (towards core of earth) Natural processes such as earthquakes, tsunamis and volcanic eruptions have been occurring since the creation of earth, but become hazards when they threaten human lives. Hazard: probability that a specific damaging event will happen within a particular period of time. Risk= f (hazard, exposure, vulnerability, coping capacity) Vulnerability: susceptibility of people and property to hazardous event.