RICHTER 15
15级地震
Q. What if a Richter magnitude 15 earthquake were to hit America at, let's say, New York City? What about a Richter 20? 25?
Q．如果美国纽约城受到一场里氏15级的地震袭击会发生什么？里氏20级，25级呢？
——Alec Farid
——亚历克•法里德
A. THE RICHTER SCALE, WHICH has technically been replaced by the “moment magnitude”1 scale, measures the energy released by an earthquake. It's an open-ended scale, but since we usually hear about earthquakes with ratings from 3 to 9, a lot of people probably think of 10 as the top and 1 as the bottom.
A．里氏震级在学术上现在已经被“矩震级”1所取代，它们都是用来衡量地震释放出的能量的多少。里氏震级没有上限，不过由于我们平时了解到的地震都在3～9级之间，因而许多人都认为最高就是10级，最低是1级。
In fact, 10 isn't the top of the scale, but it might as well be. A magnitude 9 earthquake already measurably alters the rotation of the Earth; the two magnitude 9+ earthquakes this century both altered the length of the day by a tiny fraction of a second.
事实上10级并不是上限，但实际情况下10级很有可能是最高的震级了。一场里氏9级的地震已经显著改变地球的自转了，本世纪内两场里氏9级以上的地震都使得一天的长度发生了很小的一些变化。
A magnitude 15 earthquake would involve the release of almost 1032 joules of energy, which is roughly the gravitational binding energy of the Earth. To put it another way, the Death Star caused a magnitude 15 earthquake on Alderaan.
一场里氏15级的地震释放出来的能量有将近1032焦耳能量，约相当于地球的引力结合能。换言之，死星在奥德兰星球上引起了一场里氏15级的地震2。
You could in theory have a more powerful earthquake on Earth, but in practice all it would mean is that the expanding cloud of debris would be hotter.
理论上来讲，地球上可能发生威力更大的地震，但这也只是意味着膨胀的碎片云的温度更高一些而已。
The Sun, with its higher gravitational binding energy, could have a magnitude 20 quake (although it would certainly trigger some kind of a catastrophic nova). The most powerful quakes in the known universe, which occur in the material in a superheavy neutron star, are about this magnitude. This is about the energy release you would get if you packed the entire volume of the Earth with hydrogen bombs and detonated them all at once.
太阳的引力结合能比地球更高，可能会发生里氏20级的阳震（虽然这可能会引发毁灭性的新星爆发）。已知宇宙范围内威力最大的震动发生在一颗质量极大的中子星上，震级就约为20级。释放出的能量相当于你在地球那么大的体积内堆满氢弹，然后在一瞬间引爆。
We spend a lot of time talking about things that are large and violent. But what about the bottom end of the scale? Is there such a thing as a magnitude 0 earthquake?
我们已经花了很长时间讨论庞大而剧烈的东西，如果我们走另一个极端呢？有没有震级为0级的地震？