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SNS Outfitter & Guides via Facebook

Massive 'Gash' Splits Open Foothills of Bighorn Mountains

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SNS Outfitter & Guides via Facebook

A 150-foot-wide chasm has appeared in the foothills of the Bighorn mountain range in Northern Wyoming. Images of the crack were first posted online on October 23 by local hunting outfitters SNS Outfitter & Guides.

This giant crack in the earth appeared in the last two weeks on a ranch we hunt in the Bighorn Mountains. Everyone here is calling it “the gash”. It’s a really incredible sight.Huntwyo.com

Posted by SNS Outfitter & Guides on Friday, October 23, 2015

Located 10 miles outside the town of Ten Sleeps, "the gash" stretches for 2250 feet. Although it looks like something formed by an earthquake, no seismic activity has been reported in the area. The crack is more likely a slow-moving landslide produced by an especially rainy spring and summer. Acidic rain or subsurface water can sometimes cause carbonate rocks to dissolve, and variations in underground water flow can also threaten the integrity of sediments supporting the surface layer. These factors can trigger the collapse of the surface soil in a similar way to how sinkholes are formed

In light of the curiosity surrounding their first post, SNS brought an engineer to investigate the site. On their Facebook page, they posted the follow-up, "Apparently, a wet spring lubricated across a cap rock. Then, a small spring on either side caused the bottom to slide out. He estimated 15 to 20 million yards of movement."

While cap rocks are naturally strong, the rock that lies beneath them can become unstable when infiltrated by high amounts of water. If the cap rock in this case had slipped off, it would have made the weaker rock beneath it vulnerable to rain. 

Based on the images, Seth WittkeWyoming Geological Survey’s manager of groundwater and geologic hazards and mapping, told the Powell Tribune, "A number of things trigger them, moisture in the subsurface which causes weakness in soil or geology, and any process that would weaken the bedrock or unstabilize it somehow.” Unlike more violent landslides, this one likely occurred at a more gradual pace, according to Wittke.

The survey's public information specialist Chamois Andersen also added, "It is not uncommon to have slides like that." So while unsettling, the crack is thankfully not a sign of seismic catastrophe, as some have feared.

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Geological Map Shows the Massive Reservoir Bubbling Beneath Old Faithful
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Yellowstone National Park is home to rivers, waterfalls, and hot springs, but Old Faithful is easily its most iconic landmark. Every 45 to 125 minutes, visitors gather around the geyser to watch it shoot streams of water reaching up to 100 feet in the air. The punctual show is one of nature’s greatest spectacles, but new research from scientists at the University of Utah suggests that what’s going on at the geyser’s surface is just the tip of the iceberg.

The study, published in the journal Geophysical Research Letters, features a map of the geological plumbing system beneath Old Faithful. Geologists have long known that the eruptions are caused by water heated by volcanic rocks beneath the ground reaching the boiling point and bubbling upwards through cracks in the earth. But the place where this water simmers between appearances has remained mysterious to scientists until now.

Using 133 seismometers scattered around Old Faithful and the surrounding area, the researchers were able to record the tiny tremors caused by pressure build-up in the hydrothermal reservoir. Two weeks of gathering data helped them determine just how large the well is. The team found that the web of cracks and fissures beneath Old Faithful is roughly 650 feet in diameter and capable of holding more than 79 million gallons of water. When the geyser erupts, it releases just 8000 gallons. You can get an idea of how the reservoir fits into the surrounding geology from the diagram below.

Geological map of geyser.
Sin-Mei Wu, University of Utah

After making the surprising discovery, the study authors plan to return to the area when park roads close for the winter to conduct further research. Next time, they hope to get even more detailed images of the volatile geology beneath this popular part of Yellowstone.

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Big Questions
Just How Hot Is Lava?
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Like the bubbling cheese of a pizza consumed too quickly, lava has been anointed as one of the most scorching substances on Earth. But just how hot is lava? How quickly could it consume your flesh and destroy everything in its path?

You may already know that lava is actually molten rock that oozes or spurts out of volcanoes because of the extreme temperatures found miles deep in the Earth. As the rocks melt, they begin to rise toward the surface. (Lava is typically referred to as magma until it reaches the surface.) As you can imagine, the heat that's needed to melt rock is pretty staggering. Cooler lava—relatively speaking—could be around 570°F, about the same as the inside of your typical pizza oven. On the extreme side, volcanoes can produce lava in excess of 2120°F, according to the United States Geological Survey.

Why is there so much variation? Different environments produce different chemical compositions and minerals that can affect temperature. Lava found in Hawaii from basalt rock, for example, tends to be on the hotter side, while minerals like the ones found near the Pacific Northwest's Mt. Saint Helens could be a few hundred degrees cooler.

After lava has erupted and its temperature begins to lower, it will eventually return to solid rock. Hotter lava flows more quickly—perhaps several feet per minute—and then slows as it cools, sometimes traveling only a couple of feet in a day.

Because moving lava takes its sweet time getting anywhere, there's not much danger. But what if you did, in some tremendously unfortunate circumstance, get exposed to lava—say, by being thrown into a lava pit like a villain in a fantasy film? First, you're unlikely to sink rapidly into it. Lava is three times as dense as water and won't simply move out of the way as quickly. You would, however, burn like a S'more at those temperatures, even if you wouldn't quite melt. It's more likely the radiant heat would singe you before you even made contact with the hypothetical lava lake, or that you'd burst into flames on contact.

Because lava is so super-heated, you might also wonder how researchers are even able to measure its temperature and answer the burning question—how hot is lava, exactly—without destroying their instrumentation. Using a meat thermometer isn't the right move, since the mercury inside would boil while the glass would shatter. Instead, volcanologists use thermocouples, or two wires joined to the same electrical source. A user can measure the resistance of the electricity at the tip and convert it to a readable temperature. Thermocouples are made from ceramic and stainless steel, and both have melting points higher than even the hottest lava. We still don't recommend using them on pizza.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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