Soil erosion, landslides , and flash floods can result after the vegetation cover has been burnt. Often, frequency is measured in terms of a hazard s recurrence interval. The interaction among nature, society, and technology at a variety of spatial scales creates a mosaic of risks that affect places and the people who live there. The term is normally used in reference to a specific place or region. Heavy rains and storm surges above normal tide levels are produced.
Hurricanes evolve from tropical depressions and tropical storms.
For other regionally specific terms see typhoon and cyclone . The Mercalli Scale measures intensity based on damage to structures from earthquakes and the perceptibility of the event by humans without instrumentation. Can be initiated by long rains or in combination with an earthquake . The Richter Scale measures the magnitude of earthquakes through the amount of energy released. Magnitude is an important characteristic for analyzing hazards since only occurrences exceeding some defined level of magnitude are considered extreme, disastrous, or even hazardous.