Japan Earthquake Sped Up Antarctica Ice Stream
The 9.0-magnitude earthquake that rocked Japan on Friday (March 11) and sent a tsunami travelling across the Pacific Ocean had another long-range effect: It momentarily caused a glacier in Antarctica to speed its flow, researchers have said.
The Whillans glacier, effectively a stream of ice, in West Antarctica appears to have been nudged along in its slow flow by the seismic waves of the earthquake, which radiated across the globe, reported the science news website New Scientist.
"It's an interesting insight into how large earthquakes might affect glacier motion," Jake Walter of the University of California, Santa Cruz told New Scientist.
The earthquake also shortened the length of Earth's day by 1.8 microseconds, according to one scientist's calculations.
Walter and his colleagues monitor the Whillans ice stream from California, using GPS stations placed on the ice that relay its movements.
Normally, the glacier slides only about 3 feet (1 meter) per day, but in a strong slip event, such as the one triggered by the earthquake, it can rapidly move about 1.5 feet (0.5 m).
Previous work by Walter and his team showed that the ice stream speeds up about twice a day, with each event lasting only about 30 minutes. But GPS data analyzed on Monday showed that one of these events happened earlier than expected at exactly the time the seismic waves emanating from the earthquake in Japan would have hit Antarctica.
And this earthquake isn't the only major one to have a discernable effect on the glacier's movement last year's 8.8-magnitude earthquake off the coast of Chile had a similar effect, Walter noted.
The jostling from the earthquakes likely won't contribute to any disintegration of the Antarctic ice though, Walter said. Scientists are monitoring Antarctica's ice to see what effect climate change is having on its melting.
