Japan’s earthquake, one of the largest ever recorded, appears to have moved the main island by about 2.4 metres, the US Geological Survey (USGS) says.
Friday’s magnitude 9 quake unleashed a terrifying tsunami that engulfed towns and cities on the east coast of Honshu island, destroying everything in its path.
The quake and its tectonic shift resulted from “thrust faulting” along the boundary of the Pacific and North America plates, according to the USGS.
The Pacific plate pushes under a far western wedge of the North America plate at the rate of about 83 millimetres per year, but a colossal earthquake can provide enough of a jolt to dramatically move the plates, with catastrophic consequences.
“With an earthquake this large, you can get these huge ground shifts,” said USGS seismologist Paul Earle.
“On the actual fault you can get 20 metres of relative movement, on the two sides of the fault.”
He said similar movements would have been seen for Chile and Indonesia.
Kenneth Hudnut, a USGS geophysicist, said experts read data, including that from global positioning systems, to determine the extent of the shift.
“We know that one GPS station moved, and we have seen a map from GSI (Geospatial Information Authority) in Japan showing the pattern of shift over a large area is consistent with about that much shift of the land mass,” he told CNN.
