万物简史 第299期:地下的烈火(7)（在线收听） |
The scale is of course more an idea than an object, an arbitrary measure of the Earth's tremblings based on surface measurements. 当然，里氏震级是一个概念，不是一件东西，是一个根据地面测量的结果武断地得出的地球震动的次数。 It rises exponentially, so that a 7.3 quake is fifty times more powerful than a 6.3 earthquake and 2,500 times more powerful than a 5.3 earthquake. 它以指数的上升来表示，于是7.3级地震要比6.3级地震强50次，比5.3级地震强2500次。
At least theoretically, there is no upper limit for an earthquake—nor, come to that, a lower limit. 从理论上讲，地震没有上限——因此也没有下限。
The scale is a simple measure of force, but says nothing about damage. 震级是一种测量强度的简单方法，但毫不说明破坏程度。
A magnitude 7 quake happening deep in the mantle—say, four hundred miles down—might cause no surface damage at all, 发生在地幔深处的7级地震——比如，650公里下面——可能对地面毫无破坏作用，
while a significantly smaller one happening just four miles under the surface could wreak widespread devastation. 而发生在地面以下六七公里处的小得多的地震，很可能造成大面积的破坏。
Much, too, depends on the nature of the subsoil, the quake's duration, 很大程度上也取决于底土的性质、地震持续的时间、
the frequency and severity of aftershocks, and the physical setting of the affected area. 余震的频率和烈度，以及灾区的具体情况。
All this means that the most fearsome quakes are not necessarily the most forceful, though force obviously counts for a lot. 这一切都意味着，最可怕的地震不一定是最强烈的地震，虽然强度显然很有价值。
The largest earthquake since the scale's invention was (depending on which source you credit) 自震级发明以来，最大的地震(取决于你使用哪种资料)
either one centered on Prince William Sound in Alaska in March 1964, which measured 9.2 on the Richter scale, 不是1964年3月以阿拉斯加威廉王子湾为震中的大地震，它是里氏9.2级；
or one in the Pacific Ocean off the coast of Chile in 1960, which was initially logged at 8.6 magnitude 就是1960年发生在智利近海太平洋里的大地震。后者起先记录为8.6级，
but later revised upward by some authorities(including the United States Geological Survey) to a truly grand-scale 9.5. 但后来由某些权威（包括美国地质局）往上调整为9.5级。 |
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