October Landslide in Southeast Alaska Was Among World’s Biggest in Recent Years
Yereth Rosen
Alaska Dispatch News
December 18, 2015
When 200 million metric tons of rock tumbled down a remote Southeast Alaska mountain in October, nobody was around to see it. But thanks to a beefed-up seismic network and a new system that can distinguish landslides from earthquakes, scientists knew it had happened.
The slide happened near Icy Bay and sent debris onto Tyndall Glacier, reported scientists from Columbia University’s Lamont-Doherty Earth Observatory. Some of the debris was dumped into Taan Fiord, setting off a tsunami that was big enough to be measured at the nearest tidal gauge nearly 100 miles away.
It was one of the world’s biggest landslides in recent years and the largest in North America since the collapse of Mount St. Helens in 1980, according to the observatory.
It was also part of a series of slides that have been detected in the mountains of Southeast Alaska and neighboring parts of Canada that would have likely gone unnoticed if not for a new system — developed by the Lamont-Doherty Earth Observatory scientists — that distinguishes the signals of such slides from those produced by earthquakes.
More: October landslide in Southeast Alaska was among world’s biggest in recent years