黄石超级火山或将提前喷发，你需要知道这些事

你大概听说过美国的黄石国家公园有一座超级火山吧。那你知道吗，这个超级定时炸弹的爆发时间或许比很多人预想的要早得多，留给美国人民的预警时间也很短。

亚利桑那州立大学的科研人员耗时数周时间，分析了黄石公园火山的石化火山灰沉积物，相关发现已于近日对外公布。这些沉积物中的矿物质成份表明，这座火山的温度和构造就只需要几十年可以积累到濒临喷发的程度，而不是像科学家预想的那样需要几千年的时间。

研究团队中的亚利桑那州立大学研究生汉纳•夏姆鲁对《纽约时报》表示：“一个火山系统从静止到临近喷发，只需要这么短的时间，实在令人震惊。”

这番话从一个火山专家口中说出来，是相当值得警醒的。好消息是，科学家们再研究上几十年，大概就可以精确地预测火山的下次喷发会在什么时候发生了。

有的时候，人知道得越多，就对自己的生活和生命越有掌控感。然而有些时候，人知道的越多，只会让你在自然之力面前愈发感到自己的渺小与无助，尤其是美国人民屁股下面还坐着这么一块禀性无常的大石头。

下面是关于这座超级火山的一些小科普，它可能会让你觉得宽心一些，也有可能让你更忧心。

黄石火山是唯一一座我们应该担心的超级火山吗？

当然不是了。除了黄石这个“超级炸药包”，全球大约还有20多座超级火山，其中还有三座在美国。科学家们认为，这三座中的一座平均每10万年左右就会喷发一次。

虽然黄石火山近63.1万年都没有超级喷发过，但近来进入活跃期的超级火山却并非没有。比如意大利有一座坎皮弗莱格瑞火山（Campi Flegri），这个名字翻译过来，就是“燃烧的土地”的意思。它在一万五千年前刚刚喷发过。

意大利的科研人员指出，坎皮弗莱格瑞火山已经进入了“临界状态”，也就是说它马上就要喷发了。但此次喷发的规模或将远远不及三万九千年的那一次。那次这座火山共喷射了相当于72立方英里的熔岩（又叫坎帕阶熔灰岩）。我们的远亲尼安德特人的灭绝，或许就与这次灾难不无关系。

黄石火山的喷发将使哪些地区受到影响？

如果黄石超级火山喷发了，它可能会向空中喷射出1000立方千米以上的熔岩和火山灰。

换算过来就是250立方英里，比意大利的那次灭绝性的喷发还要严重三倍。要知道，意大利的那次超级喷发形成的硫磺云甚至飘到了1200英里以外的俄罗斯。再举个例子，黄石超级火山喷发的威力，大约相当于1980年圣海伦斯火山爆发的2500倍，在那次事故中有57人遇难。

黄石超级火山的爆发将形成方圆500英里以上的火山灰云，几乎能够覆盖整个美国西部。

黄石火山爆发的威力之大，或将使整个地球陷入一个“火山冬天”。也就是说，种庄稼什么的就别想了。据联合国2012年的估算，我们现有的粮食储备将只能维持74天。（不过随着农业技术的不断创新，说不定我们能在地底下种粮食。）

超级火山是否会导致人类灭绝？

在人类灭绝的各种版本里，火山爆发排在第几名呢？据NASA称，超级火山爆发对地球生命的威胁，要远远大于任何小行星撞击的风险。

好在NASA也不是吃素的，它也有一套应对超级火山威胁的方案。这个法子跟民间偏方的放血疗法差不多，大约要耗资34亿美元，在火山上钻一个6英里的窟窿，好把憋在地底的热量释放出来一些，希望这样能避免火山的激烈喷发。

这个计划说不定能让超级火山冷却个几百年甚至几千年。它还有另一个好处——能为我们提供大量的地热能。当然，搬石头砸自己的脚的风险也是有的。一个不小心，说不定会把这座超级火药库提前引爆了。

黄石超级火山爆发的概率是多少？

虽然这项研究表明，导致超级火山喷发的条件只需要几十年就能形成，但是你这辈子亲历一次史诗级别的超级大喷发的机率还是很低的。

据美国地质调查局介绍，黄石超级火山在某一特定年份里喷发的概率只有七十三万分之一。这个机率比你中彩票的概率要高一些，不过比你遭雷劈的概率还是要低那么一丢丢。（财富中文网）

译者：贾政景

Did you know there’s a supervolcano in Yellowstone National Park? Maybe you’ve heard that it could erupt with much less advance warning than expected?

Researchers from Arizona State University spent weeks studying fossilized ash deposits from the Yellowstone volcano and recently shared their findings. The minerals in these deposits revealed that the critical changes in temperature and composition preceding an eruption build up over a matter of decades, rather than thousands of years as scientists originally thought.

“It’s shocking how little time is required to take a volcanic system from being quiet and sitting there to the edge of an eruption,” Hannah Shamloo, a graduate student at Arizona State University who worked on the research, told The New York Times.

This is an alarming thing for a volcanologist to say. The good news is that scientists are likely just decades away from being able to more accurately predict when an eruption would occur.

Sometimes knowing more about the world around us makes us feel more in control of our lives and survival. And sometimes knowing more only underscores how small and helpless we are compared to the forces of nature on the angry rock where we reside.

Here are some more facts about supervolcanoes that may or may not make you feel any better.

Is Yellowstone the only supervolcano to worry about?

No, of course not. There are about 20 others around the world and three others, besides the Yellowstone supervolcano, in the U.S. Scientists suspect that one of them erupts every 100,000 years or so.

While Yellowstone hasn’t had a super-eruption in 631,000 years, others have been active more recently. Campi Flegri, a supervolcano in Italy whose name translates to “burning fields,” had a super-eruption 15,000 years ago.

Campi Flegri is in a “critical state,” according to researchers in Italy. It’s due for an eruption soon, but it would be a minor event compared to the 72 cubic miles of molten rock it spewed in its most notorious eruption 39,000 years ago, called Campanian Ignimbrite, that likely contributed to the extinction of the Neanderthals.

What areas would a Yellowstone eruption affect?

If the Yellowstone supervolcano erupts, it could shoot out more than 1,000 cubic kilometers of rock and ash into the air.

That’s 250 cubic miles. That’s more than three times as large as the Campanian Ignimbrite eruption in Italy, which created a sulfurous cloud that floated more than 1,200 miles away to hang over Russia. That’s 2,500 times more material than Mount St. Helens expelled in 1980, killing 57 people.

An eruption at Yellowstone would result in a cloud of ash more than 500 miles wide, stretching across nearly the entire western United States.

The explosion could be so incredibly large that it could plunge the entire planet into a volcanic winter. That means it would be impossible to grow crops and current food stores would only last about 74 days, according to a 2012 estimate by the United Nations (though innovations in farming may mean that food could be grown underground).

Will a supervolcano eruption end life on Earth?

None of this sounds ideal, but how does it rank in terms of apocalyptic near-future possibilities? According to NASA, supervolcano eruptions are a bigger danger to life on Earth than any asteroid.

Luckily NASA has a plan to neutralize supervolcano threats. It would cost approximately $3.4 billion and involves drilling down just over 6 miles into the volcano in order to release heat and hopefully avoid a violent eruption.

This plan could cool the supervolcano over the course of hundreds or even thousands of years. There’s another bonus: It would become a source of geothermal energy, too. But there are considerable risks, too. It could trigger the eruption it’s meant to save us from.

How likely is it that the Yellowstone supervolcano will erupt?

Despite the fact that this new research shows conditions leading up to supervolcano eruption could occur in several decades, the chances that you will personally experience an explosion of this scale are still low.

The odds of the Yellowstone supervolcano erupting within a given year are one in 730,000, according to the U.S. Geological Survey. Here’s a little perspective: Those odds are significantly better than your chances of winning the lottery and only slightly worse than the chance you’ll be struck by lightning.