The remnants of the giant wave that hit Japan crashed into and fragmented an Antarctic ice shelf after the original tsunami, scientists say.
The same earthquake that devastated the island nation on March 11 also caused water swells only a foot tall to cause large chunks of Antarctica’s Sulzberger ice shelf to break off and form icebergs, some almost as big as Manhattan.
(PHOTOS: Dispatch from Japan: James Nachtwey’s Impressions in Words and Pictures)
Water swells, acting as echoes from the origin of the earthquake off the coast of Japan, traveled over 8,000 miles and crashed into the island continent 18 hours later. The crash caused large pieces to break off of the 260-feet-thick Sulzberger ice shelf near New Zealand.
NASA scientists say they have never seen that kind of interaction before, though they had hypothesized that it was possible. They tracked the movements of the underwater swells after seeing how powerful the original earthquake was, measuring a devastating 9.0 on the Richter scale. They knew those swells had enough momentum to cause more havoc depending on where they landed.
“We knew right away this was one of the biggest events in recent history — we knew there would be enough swell. And this time we had a source,” said Kelly Brunt, a cryosphere specialist at Goddard Space Flight Center in a NASA statement.
(PHOTOS: Ice Land)
Zachary Cohen is a contributor for TIME. Find him on Twitter at @Zachary_Cohen. You can also continue the discussion on TIME‘s Facebook page and on Twitter at @TIME.