Scientists warn of ice melt in Alaska to uncover unexpected ‘mega-tsunami’


A massive, catastrophic tsunami triggered by a landslide of reef left unstable after the glacier melts in Alaska, scientists fear – and it could happen within the next 12 months.

In May, a group of scientists in an open letter to the Alaska Department of Natural Resources (ADNR) warned of the possibility of this impending disaster in Prince William Sound.

While the potential danger of such landslides is very serious, much is unknown about when or how the disaster occurred.

It is clear that the glacier retreats along the southern coast of Alaska to Prince William Sound, about 97 kilometers (60 mi) east of Anchorage, impact the mountain slopes above Barry Arm.

Analysis of satellite imagery suggests that a large rocky trail called scarp is emerging on the mountain face above it, due to the ongoing melting caused by the retreat from the Barry Glacier Barry Arm.

This indicates an incremental, slow-moving landslide already occurring above the fjord, but if the cliff face can suddenly give way, the results can be terrible.

Although it is remote, it is an area frequented by commercial and recreational boats, including cruise ships.

Crusted lines above the Barry Glacier. (Lauren Dauphin / NASA Earth Observatory / USGS)

“It was hard to believe the first number,” geophysicist Chunli Dai of Ohio State University told one of the researchers.

“Based on the height of the deposits above the water, the amount of slippery land and the angle of slope, we calculated that a collapse would release 16 times more debris and 11 times more energy than Alaska’s 1958 Litua Bay landslide . Mega Tsunami. ”

Such results are inconceivable if the team’s calculations are correct, as the 1958 episode – which is similar to an atomic bomb explosion by eyewitnesses – is often considered the highest tsunami wave in modern times, reaching a maximum of 524 . Meter (1,720 ft).

In 2015, the occurrence of a very steep slope failure in the Tan Fiord led the tsunami to 193 meters (633 ft), and researchers say these failures could be brought about for several reasons.

The May report states, “Such slopes can turn into several possible triggers from slow creep to high-speed landslides.”

“Often, heavy or prolonged rain is a factor. Earthquakes usually trigger failures. Warm weather that drives melting of permafrost, ice, or glacier ice can also be a trigger.”

010 Barry Glacier 3(Gabe Wolken)

In the year since the release of the report, subsequent landslide analyzes have suggested little or no movement of land mass on the slope, though by itself that doesn’t tell us much, as research suggests That rock face has been shifting since at least 50 years ago, accelerating at some points, while slowing at others.

Although these types of micro variations are still being investigated, the overall view is that glacier retreat speeds increase the likelihood of more dramatic slope failures.

“When the climate changes, the landscape takes time to adjust,” the letter’s co-author and geologist Bretwood Higman told the nonprofit Ground Truth Alaska Guardian.

“If a glacier retreats really quickly it can catch the surrounding slopes by surprise – they can fail horrifically instead of slowly adjusting.”

Ongoing surveillance by several organizations, including the ADNR, National Oceanic and Atmospheric Administration, and the US Geological Survey – monitor the developments in Prince William Sound to track movements above the Barry Glacier and refine predictions from one is. There will be a mega-tsunami.

010 Barry Glacier 3Tsunami estimates. (Briggs and others., Letter to ADNR, May 2020)

Preliminary modeling from the May report, which has not yet been peer-reviewed, suggests that a tsunami reaching hundreds of feet in height with tsunamis will propagate throughout Prince William Sound, as a result of sudden massive failure, and From afar and from the fjord. Source.

Perhaps its major effect is that the effect of relatively rapid glacier retreats in climate change can pose similar landslides and tsunamis not only in Alaska, but also in many other places around the world.

“It’s really awful,” Higgman said in May at Columbia University’s GlacierHub blog, comparing environmental risks to volcanoes – something that humanity has understood as dangerous, unpredictable geography.

“Maybe now we are entering a time where we have to look at the glacier landscape with the same type of spectacles.”

The findings are available on the ADNR website.

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