Researchers from NOAA, U.S. Geological Survey and their partners have completed the first high-resolution, comprehensive mapping of one of the fastest moving underwater tectonic faults in the world, located in southeastern Alaska. This information will help communities in coastal Alaska and Canada better understand and prepare for the risks from earthquakes and tsunamis that can occur when faults suddenly move.
Since 2015, scientists have been gathering data on the Queen Charlotte-Fairweather fault system, a 746-mile long strike-slip fault line that extends from offshore of Vancouver Island, Canada, to the Fairweather Range of southeast Alaska. The team has gathered high resolution bathymetric data through multibeam sonar across 5,792 square miles of the ocean bottom.
The most recent survey came from NOAA Ship Fairweather, with USGS scientists aboard from April through July, when it collected multibeam bathymetric data in an area along the U.S. and Canadian international border in water depths ranging from 500 to more than 7,000 feet deep.
“Providing scientific information to help protect vulnerable communities is one of our most important missions,” said W. Russell Callender, assistant NOAA administrator for the National Ocean Service. “Working with USGS and our state and academic partners, allows us to speed the development of information that can help communities better anticipate and prepare for risks from tsunamis and earthquakes.”
“This project has been a great collaboration on an important scientific issue with significant implications for public safety,” said David Applegate, USGS associate director for natural hazards. “We will apply what we learn from this mapping mission to hazard assessments for Alaska’s coastal communities. Partnering with NOAA reflects the importance of addressing earthquake and associated tsunami hazards to both our missions, and it enables the USGS to bring our geologic expertise to bear on offshore fault structures that have significant onshore implications.”
Fault line activity poses a hazard to the growing populations of Juneau, Sitka, and other communities throughout southeastern Alaska, as well as more than a million annual tourists and the seafloor infrastructure critical for Alaska’s communications and offshore energy industries.