How To Kill A Volcano — Transcript

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1. 0:00Volcanoes are one of the most powerful
2. 0:01forces on Earth. Their lava can destroy
3. 0:04cities and their ash clouds can blot out
4. 0:05the sun.
5. 0:06>> [music]
6. 0:06>> And there is basically nothing we can do
7. 0:08to make sure a volcano will never erupt
8. 0:10again,
9. 0:11>> [music]
10. 0:11>> except wait for it to die. So, while we
11. 0:14wait, what is it exactly that kills a
12. 0:17volcano? Hi, I'm Cameron and this is
13. 0:20Minute [music] Earth. There are three
14. 0:21main ways a volcano can die, and the
15. 0:23first is if its supply of magma fizzles
16. 0:26out. The pushing together or pulling
17. 0:28apart of tectonic plates can cause magma
18. 0:30to form. But when those plates fuse
19. 0:32[music] together, the magma forming
20. 0:33activity stops, snuffing out the
21. 0:35volcano. Poland's Kaczawskie Hills and
22. 0:38Foothills has a whole national park
23. 0:40devoted to volcanoes that suffered this
24. 0:41[music] fate. Locals call it the land of
25. 0:44extinct volcanoes. The second way a
26. 0:46volcano can die is if it gets dragged
27. 0:48away from its magma supply. Sometimes
28. 0:50weird conditions in specific places can
29. 0:53melt the mantle, sending up a plume of
30. 0:54melting mantle rock known as a hotspot
31. 0:57that pools beneath the crust and can
32. 0:59birth a volcano. That hotspot itself
33. 1:01doesn't ever move, but the Earth's crust
34. 1:03above it does. So, the volcano will
35. 1:05eventually leave its magma supply
36. 1:07behind. But since the hotspot itself is
37. 1:09still there, when one volcano dies in
38. 1:12this way, a new one might form next to
39. 1:14it, and then a new one forms next to
40. 1:15that, and so on. The Hawaiian Islands,
41. 1:18for instance, are the newest volcanoes
42. 1:19[music] formed by a hotspot that has
43. 1:21left a trail of dead volcanoes that
44. 1:23stretches all the way to Russia. The
45. 1:25third way a volcano can die is if it
46. 1:26gets clogged. Like if conditions in the
47. 1:29mantle change and the magma flow slows
48. 1:30down, the magma that's already in the
49. 1:32volcano's vents can cool, hardening into
50. 1:34a giant plug.
51. 1:35>> [music]
52. 1:35>> 50 million years later, that plug might
53. 1:37be all that's left of the volcano. Or,
54. 1:39if the volcano's vents somehow get
55. 1:41damaged, the magma might not be able to
56. 1:43escape. In these cases, the remaining
57. 1:45magma will often find its way to a
58. 1:47different spot nearby where it can
59. 1:49escape. [music]
60. 1:50That's likely what happened when, in a
61. 1:51spectacular eruption, the largest ever
62. 1:54actually, a volcano called Toba clogged
63. 1:56itself. Evidence suggests that the magma
64. 1:58from its chamber got rerouted to nearby
65. 2:01Sinabung, which is still active today.
66. 2:03Of course, it's really, really hard to
67. 2:06tell exactly what's going on underneath
68. 2:07a volcano, so we're not always sure what
69. 2:10has happened to a volcano. In fact,
70. 2:12sometimes it's hard to tell whether a
71. 2:14volcano is actually dead. Uturuncu in
72. 2:17Bolivia hasn't erupted [music] in
73. 2:19250,000 years, so scientists assumed it
74. 2:22was long gone. But recently, it started
75. 2:24rumbling again, suggesting the
76. 2:26possibility of future volcanic activity.
77. 2:28>> [music]
78. 2:28>> It turns out that Uturuncu and other
79. 2:31quiet volcanoes like it might not be
80. 2:33dead after all. Instead, they could be
81. 2:36taking magnifcently [music] long naps.