自然災(zāi)害Naturaldisaste

1、1 Natural disaster 2 flood洪水 typhoon臺(tái)風(fēng) tsunami海嘯 tornado龍卷風(fēng) earthquake地震 drought干旱 hail冰雹 famine饑荒 sandstorm沙塵暴 debris flow泥石流 volcanic explosion火山 爆發(fā) cyclone颶風(fēng) snow storm暴風(fēng)雪 3 according to natural disasters in the form of the surface of the spheres of the different space position, can be divided in

2、to： geological disasters earthquake disasters weather climate disasters biological disasters 4 tsunami 5 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, volcan

3、ic eruptions and other underwater, landslides, and other disturbances above or below water all have the potential to generate a tsunami. 6 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 o

4、f water draining off the land and carrying a large amount of debris with it, even with waves that do not appear to be large. 7 2011 Thoku earthquake and tsunami, An aerial view of damage in the Sendai region with black smoke coming from the Nippon Oil Sendai oil refinery 8 2.drought A drought is a p

5、eriod 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. 9 types Meteorological drought is brought about when t

6、here 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. 10 11 Drou

7、ght affected area in Karnataka, India 2012 12 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 energy in the Earths crust that creates seismic waves. Earthquakes can be violent enough to

8、 toss people around and destroy whole cities. 13 Global earthquake epicenters 14 Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismica

9、lly only if there are no irregularities or asperities along the fault surface that increase the frictional resistance. 15 16 4.volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the

10、 surface. 17 Earths volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. 18 1. Large magma chamber 2. Bedrock 3. Conduit (pipe) 4. Base 5. Sill 6. Dike 7. Layers