Kenneth Hudnut, a geophysicist at the US Geological Survey, told CNN: "At this point, we know that one GPS station moved (8 feet), 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."
Reports from an Italian institute estimated that Japan earthquake shifted Earth on its axis by as much as 4 inches, CNN said.
The earthquake measuring 8.9 on the Richter scale rocked Japan on Friday and spawned a tsunami that slammed into the northeastern coast, leaving about 1,000 people dead.
Shengzao Chen, a geophysicist, explained that the quake occurred as the Earth's crust ruptured along an area about 400 km long by 160 km wide, as tectonic plates slipped more than 18 metres.
The Japan quake follows the Feb 22 earthquake in New Zealand that killed 150 people.