最危险的自然灾害是 .英语作文

Earthquake, the crust is rapid release of energy caused by the process will produce a natural phenomenon of seismic wave vibration period. Mutual compression between the plate and the plate collision on Earth, causing the edge of the plate and intraplate produce dislocation and fracture, is the main cause of earthquakes.
Location earthquake began called the source, the source just above the ground called the epicenter. The most devastating earthquake ground vibration known as a very strong point earthquake, the epicenter of the region is often located very earthquake zone. Earthquakes often cause serious casualties, can cause fires, floods, toxic gas leaks, bacteria and diffusion of radioactive substances may also cause tsunamis, landslides, avalanches, ground cracks and other secondary disasters.
According to statistics, approximately occur on Earth every year more than 500 million times earthquake, the earthquake thousands of times a day to happen. Most of them too small or too far away, so that people feel; it can really cause serious harm to human earthquake about ten to twenty times; can cause particularly severe earthquake disaster about once or twice. People do not feel the earthquake, we must use seismometers to record; different types of seismographs can record different intensity, different distances earthquake. World running with thousands of various seismic monitoring equipment day and night earthquakes trends.
The current level of technology can not yet predict the arrival of earthquakes, the future for a long period of time, the earthquake is unpredictable. The so-called successful examples of earthquake prediction, basically coincidence. For the earthquake, we should do is to improve the seismic building level, good defense, and not to predict earthquakes