百科知识视频之煎蛋小学堂47 头朝下的车为何这么屌？

On June 7,1692,the Jamaican city of Port Royal,a notorious pirate haven,sank into its own harbor.This disaster (or blessing,depending on who you ask)was caused by liquefaction of the ground following a major earthquake,and we know it happened at exactly 11:43 am thanks to a pocket watch that went down along with two thirds of the town and over 2000 people.

1962年6月7日 牙买加海盗天堂 皇家港口，在自己的港口沉没了。这场灾难 或说是福祉(这取决于你说的对象)在地震之后的地面液化造成的，我们知道事件发生在上午11时43分 一只怀表停在了此刻 还有三分之二的小镇沉没 2000余人失踪。

Liquefaction happens when waterlogged,loose soil,we call it "sand",turns into quicksand temporarily.If you look closely at land,you'll realize that it's actually comprised of tons of tiny rocks,and their roundness and roughly uniform size,mean that there's space between that can get filled by water.When we step on saturated sand at the water's edge,it's fairly stable because the particles get pushed together and rest on each other,while any excess water escapes by flowing away to where the pressure is lower.

液化发生在浸满水的松散土壤 我们称之为沙地 暂时变成流沙时。如果你仔细观察沙地 会发现它其实是由无数的小石块组成的，它们圆形的形状和几乎一致的大小 意味着其间的间歇可以被水填入。当我们踩在水边的湿沙上时，沙地仍很稳定 这是因为沙粒被挤压在一起 相互抵触，而多余的水则流到压力较低的地方。

We can(and do)build buildings on wet sandy soil,since the weight of the grains,and the friction between them makes the soil behave as a solid most of the time,But in an earthquake,soil particles repeatedly jostle back and forth so much that the water can't flow away.Loosely packed dry soils tend to compress under stress,but with incompressible water unable to escape the gaps between grains,the soil can't compress and the water takes the load.

我们的确能在湿沙质土上盖房子 因为沙粒的质量 以及相互间的摩擦力让湿土在多数时候呈现出固体特征。而地震时 土壤颗粒不停地来回碰撞 水无法流走。松散的干沙在压力下会被压缩 而当难以压缩的水 无法从沙粒间隙间流走时，土壤就无法被压缩 水占了上风。

Unfortunately,water,as a liquid,doesn't have much structural integrity,so if the saturated soil is forced to compress too much too quickly,it will start to act like a liquid,and dense objects resting on the now liquefied soil will risk.You can experience liquefaction for yourself in the water-soaked sand near the edge of a beach,It feels pretty soild if you stand still.but if you wiggle your feet,the movement causes the sand to liquefy beneath you,and you start sinking.

不幸的是 水作为一种液体 其结构完整性很差 因此如果湿土在过短时间内被过度挤压。它就会表现出液体性质，坐落于已液化土壤之上建筑就会沉下去。你可以在海滩边浸满水的湿沙上体验下液化的感觉 你站着不动时 感觉它像固体。但当你晃脚时，这动作会使你脚下的沙子液化 你便开始下沉。

On a larger scale,earthquake-induced liquefaction can swallow cars,roads,and even enormous apartment complexes.In other words,earthquakes can create quicksand,except that when the shaking stops and the soil particles are no longer suspended in water,the ground solidifies again and anything that sank becomes stuck,Which is what happened to this carrrr......

大范围而言 地震引起的土壤液化会吞没 汽车 道路 甚至是大房子。换句话说 地震会产生流沙，除了地震停止 沙粒不再悬浮在水中，地面再度固化 任何沉下去的东西都会被卡住。这就是为何这辆车这么吊....