Every year the earth experiences 30,000 earthquakes. Some are too minor to be even noticed, while others level cities. Fortunately, most are of the former variety.
根據統計，全世界每年平均發生三萬次以上的地震，小至人感覺不到、大至可以將整個都市毀滅，其中無感與輕微地震佔了絕大部分。