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How To Kill A Volcano - Video học tiếng Anh

How To Kill A Volcano

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0:00Volcanoes are one of the most powerful

0:01forces on Earth. Their lava can destroy

0:04cities and their ash clouds can blot out

0:05the sun.

0:06>> [music]

0:06>> And there is basically nothing we can do

0:08to make sure a volcano will never erupt

0:10again,

0:11>> [music]

0:11>> except wait for it to die. So, while we

0:14wait, what is it exactly that kills a

0:17volcano? Hi, I'm Cameron and this is

0:20Minute [music] Earth. There are three

0:21main ways a volcano can die, and the

0:23first is if its supply of magma fizzles

0:26out. The pushing together or pulling

0:28apart of tectonic plates can cause magma

0:30to form. But when those plates fuse

0:32[music] together, the magma forming

0:33activity stops, snuffing out the

0:35volcano. Poland's Kaczawskie Hills and

0:38Foothills has a whole national park

0:40devoted to volcanoes that suffered this

0:41[music] fate. Locals call it the land of

0:44extinct volcanoes. The second way a

0:46volcano can die is if it gets dragged

0:48away from its magma supply. Sometimes

0:50weird conditions in specific places can

0:53melt the mantle, sending up a plume of

0:54melting mantle rock known as a hotspot

0:57that pools beneath the crust and can

0:59birth a volcano. That hotspot itself

1:01doesn't ever move, but the Earth's crust

1:03above it does. So, the volcano will

1:05eventually leave its magma supply

1:07behind. But since the hotspot itself is

1:09still there, when one volcano dies in

1:12this way, a new one might form next to

1:14it, and then a new one forms next to

1:15that, and so on. The Hawaiian Islands,

1:18for instance, are the newest volcanoes

1:19[music] formed by a hotspot that has

1:21left a trail of dead volcanoes that

1:23stretches all the way to Russia. The

1:25third way a volcano can die is if it

1:26gets clogged. Like if conditions in the

1:29mantle change and the magma flow slows

1:30down, the magma that's already in the

1:32volcano's vents can cool, hardening into

1:34a giant plug.

1:35>> [music]

1:35>> 50 million years later, that plug might

1:37be all that's left of the volcano. Or,

1:39if the volcano's vents somehow get

1:41damaged, the magma might not be able to

1:43escape. In these cases, the remaining

1:45magma will often find its way to a

1:47different spot nearby where it can

1:49escape. [music]

1:50That's likely what happened when, in a

1:51spectacular eruption, the largest ever

1:54actually, a volcano called Toba clogged

1:56itself. Evidence suggests that the magma

1:58from its chamber got rerouted to nearby

2:01Sinabung, which is still active today.

2:03Of course, it's really, really hard to

2:06tell exactly what's going on underneath

2:07a volcano, so we're not always sure what

2:10has happened to a volcano. In fact,

2:12sometimes it's hard to tell whether a

2:14volcano is actually dead. Uturuncu in

2:17Bolivia hasn't erupted [music] in

2:19250,000 years, so scientists assumed it

2:22was long gone. But recently, it started

2:24rumbling again, suggesting the

2:26possibility of future volcanic activity.

2:28>> [music]

2:28>> It turns out that Uturuncu and other

2:31quiet volcanoes like it might not be

2:33dead after all. Instead, they could be

2:36taking magnifcently [music] long naps.