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地震是由于地球构造的变化而发生,地球的构造是:地球的半径为6400公里,从地面到地下数十公里为地壳,地壳下到深度2900公里止为外罩层,再下面就是地球的中心部“核”,外罩层虽然是固体但它产生大量的热对流,对流速度每年减慢数公厘,因为这个运动长年累月在进行、在变化,就影响到地壳也随之变化,这个变化达到一定程度,就产生了大的急激变化而振动,这个振动传到地表,就是地震。根据调查,从统计资料上看一般的可以说69年为一个周期(标准偏差±13年)。从公历818年起到现在止(1975年)在这1157年中,加上1923年日本关东大地震那一
Earthquakes happen due to changes in the earth’s structure. The earth’s structure is: the radius of the earth is 6,400 kilometers, tens of kilometers from the ground to the earth’s crust, the crust down to a depth of 2,900 kilometers only cover layer, then below is the center of the earth Although the outer shell is solid, it produces a great deal of thermal convection, and the convective velocity slows down by several millimeters per year because the movement has been going on over the years. As the change affects the crust, it changes to a certain extent , It produces a big radical change and vibration, the vibration spread to the surface, is the earthquake. According to the survey, it can be said from the statistical data that a period of 69 years (standard deviation ± 13 years) can be said. From the Gregorian calendar in 818 until now (1975) In this 1157 years, with the 1923 Kanto Earthquake in Japan that