A NASA scientist and her colleagues have observed that the March 11 tsunami that devastated Japan broke off Manhattan-size icebergs from Antarctica, some 8,000 miles distant.
Kelly Brunt, a cryosphere specialist at Goddard Space Flight Center, and colleagues detailed the finding in the Journal of Glaciology. The event "marks the first direct observation of such a connection between tsunamis and icebergs," NASA said.
The icebergs began separating from the Sulzberger Ice Shelf about 18 hours after the 9.0 earthquake that caused the tsunamis, and floating off into the Ross Sea. The ice hadn't moved in at least 46 years prior to the event, according to NASA.
Though the sea swell from the tsunami was only about one foot high, and the ice shelf is about 260 feet thick, the waves managed to break off enough ice to equal two Manhattans.
The scientists used data from the MODerate Imaging Spectroradiometer (MODIS), aboard satellites that view the entire Earth's surface every day or two, as well as the European Space Agency satellite Envisat.
Though previously predicted, this new knowledge of seismic activity breaking off icebergs in Antarctica can shed light on past events, NASA said.
"In September 1868, Chilean naval officers reported an unseasonal presence of large icebergs in the southernmost Pacific Ocean, and it was later speculated that they may have calved during the great Arica earthquake and tsunami a month earlier," NASA quoted collaborator Emile Okal of Northwestern University as saying. "We know now that this is a most probable scenario."