WEBVTT - BrainStuff Classics: What Makes Some Lakes Explode?

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<v Speaker 1>Welcome to brain Stuff, a production of iHeartRadio. Hey brain Stuff,

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<v Speaker 1>Lauren Vogel Bomb here with another classic from our podcast's archives.

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<v Speaker 1>This one covers a natural phenomenon that you probably don't

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<v Speaker 1>have to worry about, but that's nonetheless fascinatingly terrifying. Exploding lakes.

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<v Speaker 1>Hey brain Stuff, Lauren vogel Bomb Here. Today we're talking

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<v Speaker 1>about a rare but incredibly deadly natural phenomenon, exploding lakes

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<v Speaker 1>aka limnic eruptions. A limnic eruption is what happens when

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<v Speaker 1>deadly gases like carbon dioxide explode out of volcanic lakes.

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<v Speaker 1>Sometimes the carnage unfolds on multiple fronts. Just as lethal

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<v Speaker 1>clouds suffocate humans and animals, the abrupt displacement of water

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<v Speaker 1>is liable to create tsunamis. That exact combination of events

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<v Speaker 1>killed more than seventeen hundred people one grim summer day

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<v Speaker 1>in nineteen eighty six in the West African country of Cameroon.

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<v Speaker 1>And now sign up. Wonder if an even bigger limnic

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<v Speaker 1>eruption is in the making. But how does such an

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<v Speaker 1>explosion happen? Let's start with water pressure. Water pressure increases

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<v Speaker 1>with depth. That's why scuba divers can't venture too far

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<v Speaker 1>below the surface without the right equipment. The force that's

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<v Speaker 1>exerted upon a submerged object by the weight of all

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<v Speaker 1>the liquid above it is called hydrostatic pressure. Normally, this

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<v Speaker 1>pressure intensifies by fourteen point five pounds per square inch

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<v Speaker 1>or one hundred kilopaskels or one bar for every ten

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<v Speaker 1>meters of water depth. That's about thirty three feet. But

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<v Speaker 1>the key to limnic eruptions lies in temperature. Gases dissolve

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<v Speaker 1>more easily in cold, high pressure water. Limnic eruptions can

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<v Speaker 1>only occur in deep bodies of water with a lot

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<v Speaker 1>of hydrostatic pressure at the bottom. There must also be

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<v Speaker 1>a significant difference in both the pressure and temperature between

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<v Speaker 1>the surface water and the lower depths, with the lower

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<v Speaker 1>depths being much chillier. Stratification will act like a barrier,

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<v Speaker 1>keeping that dissolved gas confined to the lake bottom, where

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<v Speaker 1>it can't depressurize and escape out into the atmosphere. Because

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<v Speaker 1>it's trapped, the dissolved gas accumulates in massive and potentially

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<v Speaker 1>deadly quantities. Explosions are impossible in lakes whose lower and

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<v Speaker 1>upper water levels intermingle on the regular For build up

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<v Speaker 1>to occur. The water also needs a continuous supply of

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<v Speaker 1>some highly soluble gas, like carbon dioxide or methane, and

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<v Speaker 1>that's where volcanism comes in. At localities with active volcanoes,

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<v Speaker 1>buried magma is liable to send methane, CO two and

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<v Speaker 1>other gases seeping up through thin sections of Earth's crust.

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<v Speaker 1>If a lake is overhead, the gas may pass right

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<v Speaker 1>into the water, traveling by volcanic vents and other roots.

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<v Speaker 1>That brings us back to Cameroon and to its lakes.

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<v Speaker 1>NEOs and Monoun both are located in a volcanic field,

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<v Speaker 1>and both lake bottoms are oversaturated with carbon dioxide, which

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<v Speaker 1>underlying magma sends their way. On August fifteenth of nineteen

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<v Speaker 1>eighty four, some of the deep water in Monoun that

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<v Speaker 1>had been loaded up with the dissolved gas ascended to

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<v Speaker 1>the surface. No one knows why this happened. It's possible

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<v Speaker 1>that heavy rainfall and an earthquaker a landslide displaced some

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<v Speaker 1>of the lake bottom water. Regardless, as the water rose,

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<v Speaker 1>the dissolved carbon dioxide lurking inside it became depressurized and

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<v Speaker 1>formed bubbles. Those bubbles drove even more of the water

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<v Speaker 1>up to the top of the lake, resulting in a massive,

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<v Speaker 1>vowel smelling cloud of carbon dioxide gas. Under the wrong

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<v Speaker 1>set of circumstances, this gas is extremely dangerous to people.

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<v Speaker 1>Large quantities of CO two cling to the ground and

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<v Speaker 1>displaced oxygen, which can lead to death by suffocation. The

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<v Speaker 1>eruption killed at least thirty seven people, and two years later,

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<v Speaker 1>on August twenty first, nineteen eighty six, Lake NEOs experienced

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<v Speaker 1>a limit eruption of its own. Once again, there was

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<v Speaker 1>a sudden, mysterious upheaval of carbon dioxide laden water from

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<v Speaker 1>its frigid, high pressure depths, but this time the body

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<v Speaker 1>count was much higher. Carbon dioxide from the Lake Neo's

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<v Speaker 1>disaster killed approximately one thousand, seven hundred forty six people

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<v Speaker 1>and more than three thousand, five hundred demsic animals. Somewhere

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<v Speaker 1>from three hundred thousand to one point six million metric

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<v Speaker 1>tons of CO two gas burst out of the water

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<v Speaker 1>with enough force to set off a twenty meters tsunami

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<v Speaker 1>that's about sixty six feet tall. That was the last

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<v Speaker 1>recorded limnic eruption. If you're worried about a killer limnic

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<v Speaker 1>eruption coming to a lake, near you. University of Michigan

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<v Speaker 1>geoscience professor Yuxyu Jang says you probably shouldn't be. Lake

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<v Speaker 1>NEOs and Lake Monoon are located just above the equator,

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<v Speaker 1>where it tends to be warm all year round, and

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<v Speaker 1>there's just no way for a limnic eruption to happen

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<v Speaker 1>in a temperate body of water. In places where seasonal

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<v Speaker 1>temperatures vary widely, like in the Great Lakes, lake surfaces

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<v Speaker 1>often cool down, causing the water at that level to

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<v Speaker 1>sink and swap places with the layers of water beneath it.

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<v Speaker 1>Any gas is dissolved in there don't stay trapped. They're

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<v Speaker 1>released as they depressurize nearer to the surface. No gas accumulation,

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<v Speaker 1>no eruptions. However, Jiang and many of his colleagues have

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<v Speaker 1>taken a healthy interest in Lake Kivu, an up and

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<v Speaker 1>coming vacation destination on the border of Rwanda A the

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<v Speaker 1>Democratic Republic of the Congo. Why because it seems to

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<v Speaker 1>have all the necessary criteria for a truly colossal limnic eruption.

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<v Speaker 1>The lake contains about ten point five billion cubic feet

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<v Speaker 1>of carbon dioxide. That's about three hundred billion cubic meters

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<v Speaker 1>and two billion cubic feet of methane about sixty billion

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<v Speaker 1>cubic meters, all lurking near the bottom. For those gases

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<v Speaker 1>to explode from the lake's surface, the two million people

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<v Speaker 1>who live around Kivu might find themselves in jeopardy. One

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<v Speaker 1>possible solution, though, harvest those very gases as a possible

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<v Speaker 1>energy source by an extraction barge. Kivu Wat is a

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<v Speaker 1>one of a kind, two hundred million dollar facility that

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<v Speaker 1>uses an offshore barge to draw up water from the lake.

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<v Speaker 1>It then siphons off the methane and sends it to

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<v Speaker 1>a power plant, generating electricity for the area. When life

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<v Speaker 1>gives you lemons, turn it into electricity. Today's episode is

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<v Speaker 1>on the article what makes killer Lakes Explode on HowStuffWorks

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<v Speaker 1>dot com, written by Mark Mancini. Brainstuff is production of

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<v Speaker 1>iHeartRadio in partnership with HowStuffWorks dot Com and is produced

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<v Speaker 1>by Tyler Klang. For more podcasts from my heart Radio,

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