The sun shines through a light mist that hangs over Eklutna Lake. Two snowmachines ride toward a platform sitting over the deepest part of the lake. Today, a crew of five people works to dig mud out of the lake that they hope will unlock stories of Alaska’s past.
Paleoseismologists from Ghent University in Belgium study large "mega-thrust" earthquakes, which happen in subduction zones like Alaska's. The state’s 1964 earthquake was a mega-thrust, caused by a rupture of pressure built from one tectonic plate diving under another plate for hundreds of years.
The ’64 quake was the second-biggest in recorded history, costing the state about 130 lives as well as hundreds of millions of dollars. These scientists say their work could help Alaskans know when to expect the next big one.
This same crew is used to working on lakes in Chile, where their platform floats. At Eklutna Lake, there’s a more solid footing on top of the ice. The lake ice is about 2 feet thick.
Through a hole in the ice, the team lowers clear tubes that will retrieve the mud they’ll be studying over the next four years.
“This is the exciting part,” said scientist Nora Praet of her Ph.D. project. She says it’s important that the crew looks at lakes close to subduction zones.
“Lakes are very good reservoirs to preserve typical earthquake sediments,” Praet said.
The sediments are what the mountains are made of. When an earthquake starts shaking, the land slides. Those landslides create detectable layers in the soil, which the scientists can use to determine when earthquakes happened.
Maarten Van Daela is another Ph.D. student from Ghent University. He says the work the team does could be meaningful for Alaskans.
"It’s very important to have an idea about when this can occur again," Van Daela said. "Can it occur in the next 50 years? Or will it take two to three hundred years?”
The ’64 earthquake registered as a 9.2 in magnitude. Current studies indicate Alaska has seen that magnitude about once every 600 years, and the aim of this project is take a closer look at that.
The Ghent University team has weathered cold temperatures where their generators froze. They keep the rigging equipment underwater to prevent it from freezing.
The core samples they bring up are so precious, the scientists don’t want anything to corrupt them before they’re thoroughly analyzed. They use a generator to power an electric blanket that prevents ice crystals from forming on the samples until they can get them into warmer storage.
The tubes of mud the team preserves tell the story of Alaska’s past -- a story they hope will help Alaskans plan for the future.