That nine hundred years is an average—and a somewhat misleading one. According to Robert B. Smith and Lee J. Siegel in Windows into the Earth, a geological history of the region, the last major Teton quake was somewhere between about five and seven thousand years ago. The Tetons, in short, are about the most overdue earthquake zone on the planet.
900年是个平均数字——也是个会让人产生错觉的数字。罗伯特·B·史密斯和李·J·西格尔在《观察地球内部之窗口》这一部本地区的地质史里写道，蒂顿山脉地区的最后一次大地震发生在5000-7000年之前。总之，蒂顿山脉大概是这个星球上最该要发生地震的地方。
Hydrothermal explosions are also a significant risk. They can happen anytime, pretty much anywhere, and without any predictability. "You know, by design we funnel visitors into thermal basins," Doss told me after we had watched Old Faithful blow. "It's what they come to see. Did you know there are more geysers and hot springs at Yellowstone than in all the rest of the world combined?"
热液喷发也是个很大的危险。它可以随时随地发生，而又完全无法预测。“你要知道，按照路线图，我们要把游客带进温泉池，”我们看完老实泉喷水以后，多斯对我说，“人家就是来看这个地方的。你知不知道，黄石公园里的间歇泉和温泉比世界其他地方的加起来还多？”

I didn't know that.
“这我倒不知道。”
He nodded. "Ten thousand of them, and nobody knows when a new vent might open."
他点了点头：“有1万处，谁也不知道什么时候会出现一个新的喷气口。”
We drove to a place called Duck Lake, a body of water a couple of hundred yards across. "It looks completely innocuous," he said. "It's just a big pond. But this big hole didn't used to be here. At some time in the last fifteen thousand years this blew in a really big way. You'd have had several tens of millions of tons of earth and rock and superheated water blowing out at hypersonic speeds. You can imagine what it would be like if this happened under, say, the parking lot at Old Faithful or one of the visitors' centers." He made an unhappy face.
我们驱车来到一个名叫鸭湖的地方，那是一片200米宽的水面。“表面上看，湖面上平静无事，”他说，“它不过是个大池塘。但是，这儿过去没有这个大坑。15000年前的某个时候，这儿发生了一次大喷发。几千万吨泥土和岩石以及高热的水以高超声速炸开了。你可以想像，要是在老实泉的停车场下面，或哪个游客中心下面发生这种事，那会是个什么情景。”他脸上露出不快的神色。