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Cracks & Fissures In The Landscape

EnolaGaia

EnolaGaia

I knew the job was dangerous when I took it ...
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NOTE: Subsidence conditions are responsible for both sinkholes and the features described below. However, IMHO the structural differences between these features are sufficient to warrant a separate thread for large-scale cracks and fissures.


Splitsville: 2-Mile-Long Crack Opens in Arizona Desert

A gaping, 2-mile-long crack has opened in the barren earth in Arizona, and it will likely continue to grow, geologists say.

Recent footage from a flyover by an Arizona Geological Survey drone revealed the extent of the huge fissure in Pinal County, between Casa Grande and Tucson, showing the enormous gash splitting the barren land. The crack is so big that it dwarfs people walking along its edges in the video.

The northern part of the fissure, which is older and partially filled in, is shallow, while the southern portion is tens of feet deep in some spots, according to Joseph Cook, a geologist with the Arizona Geological Survey (AZGS).

"Some areas are about 10 feet [3 meters] across and up to 25-30 feet [7.5 to 9 m] deep (tapering crack, narrowing with depth), while others are a narrow surface crack less than an inch across," Cook told Live Science in an email. "These narrow sections sometimes have open voids underground, so collapse of the overlying material is possible — this is how the deep open portions of the fissure formed."

Cook first spotted the gargantuan crack in Google Earth imagery from December 2014. "When I went out to map the fissure, I realized the fissure was much longer than what was apparent in the Google imagery, almost 2 miles [3 kilometers] long in total," Cook said.

After mapping the fissure using GPS, Cook said, they got another look using a drone.

Water withdrawal, primarily for agriculture, is the culprit, Cook said. As groundwater is pulled up, it leaves a void and the land above it subsides, leading to cracks. Arizona is full of these cracks, Cook said. "We see earth fissures forming around the margins of these subsidence areas and along mountain fronts within the subsidence areas," Cook said.

Cook and others with the AZGS have set up 26 study areas where they've mapped a total of 170 miles (275 km) of these earth fissures.

Not only does Cook expect the crack to lengthen, but the opening beneath the surface is likely bigger than what can be seen.

"I am sure the length of this fissure will increase over time, we are only seeing the surface crack of what collapsed, the underlying fissure is longer," Cook said.

"The crack is worrisome, but it's out in the middle of the desert with nothing nearby," Cook said. His main concern is that someone riding an off-road vehicle could stop by the crack, get off the vehicle to explore it, fall in and get stuck or buried.
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SOURCE / PHOTOS: http://www.livescience.com/57663-giant-crack-opens-in-arizona-desert.html
 
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It would seem counter-intuitive to locate temples and sacred sites atop known seismic faults, but evidence suggests this may have been the case ...

Did Ancient Greeks Deliberately Build Temples on Earthquake Faults?
Archeologists and other scientists have long known that intoxicating gases emanating from water flowing from deep within the earth likely produced the visions of the oracle of Delphi, a seer who guided ancient Greeks with her prophecies from around 800 BC through the 4th century AD from her temple on Mount Parnassus.

Now new research suggests many other Greek sacred sites were built on similar fissures created by earthquakes throughout the Eastern Mediterranean.

"The ancient Greeks placed great value on hot springs unlocked by earthquakes," said Iain Stewart, professor of geoscience communication and director of the Sustainable Earth Institute at the University of Plymouth in Britain. "But perhaps the building of temples and cities close to these sites was more systematic than has previously been thought."

In a study published recently in the Proceedings of the Geologists' Association, Stewart showed how temples and other structures at Mycenae, Ephesus, Cnidus, and Hierapolis were, like Delphi, built and rebuilt over earthquake faults. ...
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SOURCE: http://www.livescience.com/60447-ancient-greeks-built-temples-earthquake-faults.html
 
Here's a new - and quite large - fissure that's recently appeared in Kenya ...

Massive Rift Valley Split in Kenya, Geologists Say it'll Form a New Continent
A section of Rift Valley is slowly splitting in what geologists say is as a result of massive earth movements, coming after deep fissures occurred in Narok County.

Over the past two weeks, a tear of up to 50 meters deep and 20 meters wide occurred along the Mai-Mahiu-Narok highway, rendering the road impassable. ...

The fissure in Suswa area has so far displaced several families after it ran through their compounds.

One of the victim, 72-year-old Mary Wambui said “staying here is like courting death”. She said her family was taking dinner last Monday when the earth suddenly cracked beneath their feet, splitting their home into two. ...
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RiftValleyCrack.jpg

FULL STORY: http://www.mwakilishi.com/article/k...-kenya-geologists-say-itll-form-new-continent
 
This sort of stuff is misleading. Rifts just don't "split a continent in two" overnight. There isn't one big crack and it all falls apart. There are tensional forces that cause earthquakes, scarps, and sinking. Then erosion smooths it over and eventually, the sea takes over. It's highly annoying to me how the doomsday folks mess up geology. (I've started a segment on my podcast to talk about this called "Apocalypse Right Now". Every day, they think the damn sky is falling.
 
Sharon Hill said:
This sort of stuff is misleading. Rifts just don't "split a continent in two" overnight. There isn't one big crack and it all falls apart. ...
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Agreed ... I suspect the journalist who finalized the article should have been more careful in creating the title.
 
I don't think they expect it to happen over night. Perhaps in one million years.
Here's a video about the cracks in Ethiopia.
 
Vardoger said:
I don't think they expect it to happen over night. Perhaps in one million years.
Here's a video about the cracks in Ethiopia.
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Have you seen the comments on these sorts of stories? WOO, Boy. I'm afraid plenty of people do think it happens overnight and represents the earth self-destructing. Scientifically-aware people don't think that but the public is generally not very knowledgeable about how geology works.
 
The new Kenyan crack is already motivating debate about its cause. Some simply attribute it to tectonic factors, but others suggest it may have more to do with groundwater-induced subsidence.

How Did a Miles-Long Crevice Appear in the Earth Overnight?
... Not only has it divided the land, but the crack is dividing scientists, who can’t quite seem to come to one conclusion as to how the natural phenomenon occurred.

Geologist Ben Andrews believes the crack is a result of tectonic plates shifting.

"We’re seeing a crack that in all likelihood formed over many thousands of years, or hundreds of thousands of years," Andrews told CBS News. ...

But, earthquake geologist Wendy Bohon disagrees.

While she does believe that Africa will split into two in the future, she believes this crevice was caused by the weather.

“I think it’s an earth fissure, the same sort of thing you see in Arizona after heavy rainstorms,” Bohon explained. “They’re the result of heavier torrential rains that come and wash away large portions of the dirt.”

What Bohon’s theory does not explain, however, is how the crevice formed along the very point scientists have expected the continent to split.
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SOURCE: https://www.yahoo.com/news/did-miles-long-crevice-appear-173525145.html
 
The island of Hawaii has now managed to get 22 volcanic fissures.

Here's a live stream from one of them.
 
Land collapse in Arizona caused by over-pumping water from aquifers is causing surface fissures to proliferate.
Land fissures, falling earth levels feared with new Arizona water rules

Arizona is adopting a new regional water-use plan, and residents and geologists fear it could lead to more man-made geological changes in the landscape, including land levels falling and giant fissures splitting the earth.

As part of the Colorado River Drought Contingency Plan, approved by Gov. Doug Ducey in 2019, Arizona must curtail river water use to keep levels at Nevada's Lake Mead from dropping to dangerous levels. ...

Farmers, facing drought conditions, want to return to ground pumping of the state's already-low ancient underground aquifers. Elsewhere in the state, where water is not regulated, out-of-state agriculture operations have moved in to drain underground water supplies. ...

Arizona's farmers have been pumping groundwater out of aquifers since 1900, and over-pumping has caused the ground levels to fall in 3,400 square miles of the state, geological mapping shows. Large fissures, some miles long, have opened up where land has collapsed.

RELATED Drought hobbles farmers in California, Texas, Florida
Earth fissures can open overnight, usually after monsoon season in June through September, said Chris Wanamaker, assistant engineer in Pinal County, where most of the state's fissures are found. ...

At first, a small crack in the earth appears where the ground-level has dropped due to over-pumping, Wanamaker said. "A heavy rain brings water runoff into the crack, which can cause the land to erode suddenly as it collapses into the void," he said.

"It's kind of Biblical, when you think about the earth opening up, like an apocalypse or something," said Joseph Cook, a research scientist and fissures expert at the Arizona Geological Survey at Tucson's University of Arizona. ...

Queen Creek resident Joan Etzenhouser has four fissures, including one under her house, on her 3-acre property about 30 miles southeast of Phoenix. After monsoon rainfalls, the fissures sometimes open into gaping trenches, 6 to 10 feet wide and 30 feet deep. ...

The moving ground under her home has broken water lines twice and cracked tiles inside, Etzenhouser said. She's filled the gap under her home with cement slurry.

"It can't really be fixed because a fissure is impossible to fix," she said. "I like where I live, but nobody's going to buy it. It's a worthless house on a worthless piece of property." ...
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FULL STORY: https://www.upi.com/Top_News/US/202...d-with-new-Arizona-water-rules/7591588108728/
 
Theres a place on the Isle of Man called `The Chasms`

A Victorian picnicing spot. Its quite charming
 
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