地震知识介绍（Introduction to seismic knowledge）.doc

地震知识介绍（Introduction to seismic knowledge） 1 what we are looking at now is the current global plate tectonics and plate motion map. Earthquakes are mostly located in unstable parts of the earth, especially the boundary between plates, forming an active seismic belt. There are mainly three seismic belts in the world: First, the circum Pacific seismic belt Two is the Eurasian seismic belt The three is the mid ocean ridge seismic zone (which stretches three of the worlds oceans (i.e. the Atlantic, Pacific and India ocean ridge) and Arctic sea) As you can see, earthquakes are quite frequent. In China, earthquakes are mainly concentrated in the following areas. 2 China earthquake belt distribution: First, North China Earthquake area: Second. Qinghai Xizang Plateau earthquake area: Third. Xinjiang earthquake zone, Fourth 、 Taiwan earthquake area Fifth, Southern China earthquake zone southeast coastal seismic belt There is an important classification criterion between earthquakes, that is, the magnitude of an earthquake, calculated by the energy released during an earthquake The formula is M=LgA, that is, the energy difference between two adjacent classes is 31.6 times (sqrt (1000)). The approximate intensity scale established by China is as follows: Chinese seismic intensity scale Level 1: no sense - only the instrument can record; Level 2: micro sense - a particularly sensitive person who has a sense of complete stillness; 3 level: less sense - a few people in the room in the sense of stillness, hanging slightly swinging; 4 levels: more sense - most people in the room, a small number of outdoor sense, dangling objects unstable, utensils sound; 5: wake up - most people feel outdoors, livestock restless, doors and windows sound, cracks appear on the wall surface; Level 6: panic - people standing instability, domestic flight, ware turned down, the primitive hut damage, landslide scarp; Level 7: housing damage: minor damage to housing, housing, chimney damage, surface cracks