USGS Scientists Go into the Alaska Wilderness

Six geologists spent 10 days in the Alaska wilderness this past summer to learn more about one of the fastest-moving earthquake faults in America.  Project leader Rob Witter led a team on the expedition to the Fairweather Fault, only accessible by float plane, with the group camping outdoors along Crillon Lake during their field work.

It is a region where a magnitude 7.7 earthquake struck Lituya Bay, Alaska in 1958 — leading to a tsunami that devastated the area. The largely uninhabited area around the bay is a part of the Glacier Bay National Park and Preserve and sits on top of the Fairweather fault.   The geologists wanted to pick up where their scientific predecessors left off almost sixty years ago, and to learn more about this hazardous fault using modern techniques—namely satellite-imaging and lidar-mapping. (Lidar, which stands for Light Detection and Ranging  is a technology similar to radar and is used to create high-resolution digital elevation models.)  

Back in 1958, immediately after the earthquake, geologists Don Miller of USGS and Don Tocher of University of California, Berkeley had surveyed parts of the ground rupture accessible by helicopter. Until recently, their observations were virtually all that was known about the seismic potential of the southern Fairweather Fault on which the 1958 quake occurred.

In June 2016, Witter and his geological field team ventured forth.  Witter and Adrian Bender, Chris DuRoss, Peter Haeussler, Richard Lease and Kate Scharer shared their complementary scientific specialties, ranging from lidar imaging and understanding mountain-building, to trenching across the fault for prehistoric quakes. “We hope our research will shed light on how often the fault has produced large earthquakes like it did in 1958,” Witter said.  

A rupture on the Fairweather Fault could negatively impact not only small communities but also a larger area in southeast Alaska.  For example, earthquake-produced landslides can affect infrastructure and lifelines that connect the state capitol, Juneau, to the rest of the globe.

The valuable research came through long, hard work.  Every day the group hiked for hours, gaining at least 1600 feet in elevation and often arriving at their destination in the rain: wet, tired and hungry.

“We would hole up in a bunch of trees and eat lunch and drink hot tea. Then get on to digging dirt, trenching, photographing and surveying,” Witter said.  “The most rewarding thing was  working with such a skilled and solid team of scientists. It is extremely rewarding to work with dedicated, thoughtful, and insightful people,” he said.  The team hopes to return next year.

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