产生地面下陷的原因有许多。很小的一块地方可能突然塌下去,或者整个一座城市——威尼斯就是一个很好的例子——可能慢慢地下沉。近年来威尼斯下沉的速度一直在增加。其原因可能就是为了给城市供水而不断地增加从井里抽水的结果。地下水的压力减小使地面下沉时会发生严重的下陷。现在已经停止抽水了,但是威尼斯仍然在下沉,尽管速度慢了一些。 There are many reasons for the ground subsidence. A small area may suddenly collapse, or the entire city - Venice is a good example - may slowly sink. In recent years, the speed of sinking in Venice has been increasing. The reason may be that in order to supply water to the city, the result of pumping water from the well continuously increases. The reduction in groundwater pressure causes serious subsidence when the ground sinks. The pumping has now stopped, but Venice is still sinking, albeit slowly.