|
点击查看： Passage One Words: 1,036 Earthquakes A) An earthquake is one of the most terrifying phenomena that nature can dish up. We generally think of the ground we stand on as rock-solid and completely stable. An earthquake can shatter that perception instantly, and often with extreme violence. B) Up until relatively recently, scientists only had unproven guesses as to what actually caused earthquakes. Even today there is still a certain amount of mystery surrounding them, but scientists have a much clearer understanding. There has been enormous progress in the past century. Scientists have identified the forces that cause earthquakes, and developed technology that can tell us an earthquakes magnitude and origin. The next hurdle is to find a way of predicting earthquakes, so they dont catch people by surprise. In this article, well find out what causes earthquakes, and well also find out why they can have such a devastating effect on us. C) An earthquake is a vibrationthat travels through the earths crust. Technically, a large truck that rumbles down the street is causing a mini-earthquake, if you feel your house shaking as it goes by; but we tend to think of earthquakes as events that affect a fairly large area, such as an entire city. All kinds of things can cause earthquakes: volcanic eruptions, meteorimpacts, underground explosions , collapsing structures . But the majority of naturally-occurring earthquakes are caused by movements of the earths plates. | 
