大自然的自动润滑系统(双语有声)
作者：ember
来源：沪江论坛
2010-07-05 14:05
Auto-Lube Keeps Parts Of San Andreas Quiet
圣安地列斯断层部分区域的自动润滑系统使其保持平静
The North American and Pacific plates meet in California at the San Andreas fault. The plates grind past each other there at as much as an inch-and-a-half a year. Until the plates jam. Then energy builds up, and eventually they lurch - an earthquake.
太平洋板块和北美板块在加州圣安地列斯断层交汇相接。这两个板块以每年一英寸半的速度摩擦、碰撞、相向运动。直至两个板块间紧紧挤压，使能量逐渐聚集，最终使两个板块急倾、错裂，酿成地震。
But on some active portions of the fault, the plates tend to just creep along, without many violent jerks. All thanks, it turns out, to a little mineral lube, according to a study in the journal Geology.
不过在断层的活跃部分，两个板块似乎仅仅是在缓慢滑动，还没有发生强烈的错动。根据《地质学》杂志上刊登的研究，这都要感谢矿物润滑油——正是这小小的矿物润滑油促成了这一现象。
Geologists got rock cores from two miles down, at the active fault zone. They looked at those fault rocks with an electron microscope. And they found an incredibly thin coating of clay polish on the rocks.
地质学家们在断层带活跃区域的两英里深处采集了岩心样本，他们利用电子显微镜研究那些断层岩，发现这些岩石上覆盖着极薄的一层粘土“抛光蜡”。
They say that clay layer apparently lubricates the plates - like greasing ball bearings - and that it's deposited there by mineral-rich water, sucked into the fault's nooks and crannies. As the fault moves, it opens new cracks for the fluid to get into, which means more lube, and more smooth creeping. A process that's been going on for millions of years. So given enough time, parts of the fault seem to develop their own earthquake prevention mechanism. But for other sections, the clock's still ticking.
地质学家们表示，显然，粘土层在两个板块之间起着润滑作用——就像润滑滚珠轴承那样，而且，粘土层能存积在两板块间是因为断层的角落与缝隙吸入了富含矿物质的水分。当断层运动时，会形成新的裂缝，而液体会流入其中，这就意味着缝隙间有着更多的润滑油，相互的摩擦、移动也更平滑。这一过程持续了数百万年。因此，这样长此以往，一部分断层似乎形成了自己的地震预防机制。不过，对于其他部分，地震危机依然迫在眉睫。
-Christopher Intagliata
声明：音视频均来自互联网链接，仅供学习使用。本网站自身不存储、控制、修改被链接的内容。"沪江英语"高度重视知识产权保护。当如发现本网站发布的信息包含有侵犯其著作权的链接内容时，请联系我们，我们将依法采取措施移除相关内容或屏蔽相关链接。
沪江网校夏季课程上线，足不出户，和沪江网校一起天天向上，共同进步吧！
