Name: What Happened To This Car?
Uploaded: 2021-04-30T02:05:46.000Z
Duration: 2 min 16 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

On June 7, 1692, the Jamaican city of Port Royal, a notorious pirate haven, sank into

Basic passive voice

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 pocketwatch that went down along with two thirds of the town and over 2000 people.

Liquefaction happens when waterlogged, loose soil (we call it "sand") turns into quicksand

If you look closely at sand, you'll realize that it's actually comprised of tons of tiny

rocks, and their roundness and roughly uniform size mean there's space between them that

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

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

Loosely packed dry soils tend to compress under stress, but with incompressible water

in the gaps between grains (which can't escape), the soil can't compress and the water takes

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 sink.

You can experience liquefaction for yourself in the water-soaked sand near the edge of

a beach - it feels pretty solid if you stand still, but if you wiggle your toes, the movement

causes the sand to liquefy beneath you, burying your feet.

On a larger scale, earthquake-induced liquefaction can swallow cars, roads, and even enormous

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

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What Happened To This Car?

stick

enormous

scale

realize