A hazard is a potentially damaging physical event, phenomenon, or human activity that may cause loss of life or injury, property damage, social and economic disruption, or environmental degradation. Hazards can have natural or human-made origins or a combination of these. The risk posed by a hazard depends on how likely it is, and where, how often, and with what intensity it takes place. For example, a small earthquake in a desert region that occurs once in 100 years poses a very low risk for people. An urban flood that occurs to a height of 3 meters within 48 hours once every 5-10 years has a relatively high probability and requires mitigation measures.