One of the Continent’s Largest Landslides Strikes Alaska
On June 11th in a quiet valley of Alaska’s snowy white wilderness a massive landslide sent tons of rocks and ice plummeting 5.5 miles down a glacier. The landslide, located in Glacier Bay National Park, was “one of the biggest ever seen in North America”. It was so large in nature that it even created its own seismic rumblings which resulted in a 3.4 magnitude earthquake. This has led to yet another indication that the earth’s temperatures are heating up.
It all began just beneath the ridgeline of the 11,750-foot Lituya Mountain when the debris cascaded through the maze of an unnamed valley before rolling over the back of John Hopkins Glacier. A blanket of muddy debris now sits upon a pristine white landscape attributing to a “chocolate frosting on a cake” comparison made by National Parks Traveler Kurt Repanshek.
Research geomorphologist, Marten Geertsema made a statement regarding the monumental event saying, “I don’t know of any rockslides that are bigger” when comparing past rockslides that occurred in North America. “If someone had been standing in front of the slide, the air blast alone would have flattened that person,” he said. There were no reported deaths in the incident.
The geological phenomenon went unnoticed for nearly one month until a pilot flew over the area when he then captured some aerial photos of the aftermath. The likelihood of the earthquake being the cause for the slide was ruled out which has pointed to the possibility of degrading permafrost. Regions that host glaciers, snow, and permafrost are more prone to landslides even in a stable climate but collected research from worldwide slope failures shows that climate change stands out as the likeliest catalyst.
The frequency of rockslides in the last few decades have experts convinced that thawing glaciers and above average temperatures have played some role in it all. Earlier signs that support this theory occurred during a particular warm week on Mount Cook in New Zealand when 12 million cubic meters of rock and ice descended off the east face of the Southern Alps. The landslide careened down ice fields and plummeted to the valley floors travelling over 4.5 miles in distance.
The landslide that took place 21 years ago was analyzed by an international team of researchers. The temperatures were recorded one week prior to the slide at the base of the detachment zone, which warmed to 14.4 degrees Celsius and quickly cooled to subfreezing temperatures. A sudden fluctuation in temperature followed by unusually warm readings caused an increase in melting and water production, which weakened the rock’s strength. The sudden refreezing of the ice did not allow the melted water to flow out, resulting in destabilizing pressure changes within the mountain.
Geertsema says that global warming may or may not be the case of the recent Alaskan landslide.
“With permafrost degradation there’s a whole complex suite of fractures that develop. Some of them dialate, so they open and close, but some of them are permanent,” he said. “And over time it progressively weakens, the rock mass. It could have been just ready to go. It’s hard to know what the factors are.”
Climate change can sometimes reveal itself through geophysical interruptions in the earth like volcanic eruptions, earthquakes, and massive landslides. It’s evident that the consequences of changing temperatures has resulted in more frequent landslides in high mountainous regions worldwide. However, more research is necessary in order to fully understand the causes. Scientists are presently concerned about rapidly rising temperature in the Andes Mountains which could cause a landslide of epic proportions. The hope is that temperatures will stabilize keeping that catastrophe and others alike at bay.
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