Looming Landslide in Alaska Could Trigger Enormous Tsunami at Any Moment, Scientists Warnhttps://earther.gizmodo.com/looming-landslide-in-alaska-could-trigger-enormous-tsun-1843479019The collapse of an unstable mountain slope in Alaska could trigger a catastrophic tsunami in Harriman Fjord. A retreating glacier is producing this precarious situation, highlighting yet another type of hazard caused by climate change.
“The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves [9 meters] in some distant bays, including Whittier. Field measurements and further analysis could allow us to make these estimates more accurate and specific.”
... Alaska is no stranger to landslide-induced tsunamis. Only July 9, 1958, an earthquake triggered a landslide in Lituya Bay, releasing an estimated 40 million cubic yards (30 million cubic meters) of material. The ensuing splash reached more than 1,700 feet (530 meters) in height. A gigantic wave then rolled through the fjord, knocking over trees and killing five people.
More recently, a 2015 landslide near Alaska’s Taan Glacier produced a 633 feet (193 meter) wave in Taan Fjord that smashed into the opposite wall of the glacial valley. And in 2017, a landslide in Greenland produced a tsunami that roared into a small, isolated community.
The looming tsunami in Harriman Fjord, however, would dwarf these previous examples. The scientists estimate a potential volume of collapsing material could be as high as 500 million cubic meters, and with a potential energy roughly 10 times greater than any of the previous events in Alaska. As the New York Times reported, this amount of material is “several hundred times the volume of Hoover Dam.”