How To Kill A Volcano

[00:00] Volcanoes are one of the most powerful

[00:01] forces on Earth. Their lava can destroy

[00:04] cities and their ash clouds can blot out

[00:05] the sun.

[00:06] >> [music]

[00:06] >> And there is basically nothing we can do

[00:08] to make sure a volcano will never erupt

[00:10] again,

[00:11] >> [music]

[00:11] >> except wait for it to die. So, while we

[00:14] wait, what is it exactly that kills a

[00:17] volcano? Hi, I'm Cameron and this is

[00:20] Minute [music] Earth. There are three

[00:21] main ways a volcano can die, and the

[00:23] first is if its supply of magma fizzles

[00:26] out. The pushing together or pulling

[00:28] apart of tectonic plates can cause magma

[00:30] to form. But when those plates fuse

[00:32] [music] together, the magma forming

[00:33] activity stops, snuffing out the

[00:35] volcano. Poland's Kaczawskie Hills and

[00:38] Foothills has a whole national park

[00:40] devoted to volcanoes that suffered this

[00:41] [music] fate. Locals call it the land of

[00:44] extinct volcanoes. The second way a

[00:46] volcano can die is if it gets dragged

[00:48] away from its magma supply. Sometimes

[00:50] weird conditions in specific places can

[00:53] melt the mantle, sending up a plume of

[00:54] melting mantle rock known as a hotspot

[00:57] that pools beneath the crust and can

[00:59] birth a volcano. That hotspot itself

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

[01:03] above it does. So, the volcano will

[01:05] eventually leave its magma supply

[01:07] behind. But since the hotspot itself is

[01:09] still there, when one volcano dies in

[01:12] this way, a new one might form next to

[01:14] it, and then a new one forms next to

[01:15] that, and so on. The Hawaiian Islands,

[01:18] for instance, are the newest volcanoes

[01:19] [music] formed by a hotspot that has

[01:21] left a trail of dead volcanoes that

[01:23] stretches all the way to Russia. The

[01:25] third way a volcano can die is if it

[01:26] gets clogged. Like if conditions in the

[01:29] mantle change and the magma flow slows

[01:30] down, the magma that's already in the

[01:32] volcano's vents can cool, hardening into

[01:34] a giant plug.

[01:35] >> [music]

[01:35] >> 50 million years later, that plug might

[01:37] be all that's left of the volcano. Or,

[01:39] if the volcano's vents somehow get

[01:41] damaged, the magma might not be able to

[01:43] escape. In these cases, the remaining

[01:45] magma will often find its way to a

[01:47] different spot nearby where it can

[01:49] escape. [music]

[01:50] That's likely what happened when, in a

[01:51] spectacular eruption, the largest ever

[01:54] actually, a volcano called Toba clogged

[01:56] itself. Evidence suggests that the magma

[01:58] from its chamber got rerouted to nearby

[02:01] Sinabung, which is still active today.

[02:03] Of course, it's really, really hard to

[02:06] tell exactly what's going on underneath

[02:07] a volcano, so we're not always sure what

[02:10] has happened to a volcano. In fact,

[02:12] sometimes it's hard to tell whether a

[02:14] volcano is actually dead. Uturuncu in

[02:17] Bolivia hasn't erupted [music] in

[02:19] 250,000 years, so scientists assumed it

[02:22] was long gone. But recently, it started

[02:24] rumbling again, suggesting the

[02:26] possibility of future volcanic activity.

[02:28] >> [music]

[02:28] >> It turns out that Uturuncu and other

[02:31] quiet volcanoes like it might not be

[02:33] dead after all. Instead, they could be

[02:36] taking magnifcently [music] long naps.