SAN FRANCISCO — Most of the news regarding the Thwaites Glacier, a Florida-sized slab of ice that is melting and currently contributing about 4 percent of global sea level rise, is bad. But a bit of good news may have emerged.
Glaciers flow somewhat like rivers, but much slower. Where Thwaites outlets into the ocean, it connects to a floating shelf of ice that braces and partially restrains the glacier. That ice shelf was once pinned upon an underwater mountain, which helped stabilize it (SN: 12/13/21). But now the shelf is so deteriorated that it’s basically unhitched, Erin Pettit, a glaciologist at Oregon State University in Corvallis, said at the news event.
Fortunately, though, the glacier “is not going to suddenly flow off land,” thanks partly to what’s been discovered upstream, said Pettit, who was not involved in the discovery.
More than 70 kilometers inland from Thwaites’ ice shelf, Hofstede and his colleagues conducted a seismic survey to probe the glacier’s underbelly. The team attached a 1.5-kilometer-long daisy-chain of seismometers to a vehicle equipped with a vibrating plate. Then they drove a roughly 200-kilometer-long stretch of the glacier, using the plate to generate seismic waves and the seismometers to record the waves’ reflectance off layers of ice and earth below. “It’s almost like radar,” said Hofstede, of the Alfred Wegener Institute Helmholtz Center for Polar and Marine Research in Bremerhaven, Germany.
2023-12-19 08:00:00
Original from www.sciencenews.org
rnrn