In DepthGeophysics

Seismic array shifts to Alaska

See allHide authors and affiliations

Science  06 Oct 2017:
Vol. 358, Issue 6359, pp. 22
DOI: 10.1126/science.358.6359.22

You are currently viewing the summary.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Summary

On 27 September, near the coastal city of Wainwright, Alaska, the last of 193 seismic stations was installed—completing a grid of 280 instruments that stretches across Alaska and northwest Canada, and kicking off the final phase of the USArray project. In 2004, the phalanx of transportable stations began advancing eastward across the lower 48, using the shivers of earthquakes to create a picture of the crust and mantle below North America. Now, for the next 2 years, these stations will plumb Alaska's depths, illuminating deep-Earth structures as well as registering the shallow tremors of earthquakes and volcanic eruptions. Moving the array to Alaska wasn't easy. Stations had to be outfitted with banks of batteries for storing solar power through the long, dark Arctic winter. And hardware was packed inside refrigerator-sized sheds that could be suspended from helicopters and plopped down in far-flung spots. With the $45 million project in place, scientists will begin to examine one of the most active subduction zones on the planet, where the Pacific Ocean's tectonic plate dives under North America's in a grinding collision that generates earthquakes and volcanoes. Much of the region is made up of slivers of marine sediments and rocks that were scraped off the subducting slab onto the continent. Studying the thickness of Alaska's crust could help geologists define these fragments and understand how the state was assembled. The array should also give researchers a glimpse of the subducting slab itself.