自然灾害Natural disaster.pptx

Natural disaster flood洪水 typhoon台风 tsunami海啸 tornado龙卷风 earthquake地震 drought干旱 hail冰雹 famine饥荒 sandstorm沙尘暴 debris flow泥石流 volcanic explosion火山爆发 cyclone飓风 snow storm暴风雪 according to natural disasters in the form of the surface of the spheres of the different space position, can be divided into： geological disasters earthquake disasters weather climate disasters biological disasters tsunami A tsunami, also known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater, landslides, and other disturbances above or below water all have the potential to generate a tsunami. The damage Tsunamis cause damage by two mechanisms: the smashing force of a wall of water travelling at high speed, and the destructive power of a large volume of water draining off the land and carrying a large amount of debris with it, even with waves that do not appear to be large. 2011 Tōhoku earthquake and tsunami, An aerial view of damage in the Sendai region with black smoke coming from the Nippon Oil Sendai oil refinery 2.drought A drought is a period of below-average precipitation in a given region, resulting in prolonged shortages in its water supply, whether atmospheric, surface water or ground water. A drought can last for months or years, or may be declared after as few as 15 days. types Meteorological drought is brought about when there is a prolonged time with less than average precipitation. Agricultural droughts are droughts that affect crop production or the ecology of the range. Hydrological drought is brought about when the water reserves avail aquifers, lakes and reservoirs fall below the statistical average. Drought affected area in Karnataka, India 2012 3.earthquake An earthquake (also known as a quake, tremor or temblor) is the perceptible shaking of the surface of the Earth, resulting from the sudden release of energ