(Adds details on aftershocks)
WASHINGTON, March 11 (Reuters) - The U.S. Geological Survey upgraded to 8.9 the magnitude of the major earthquake off the northeast coast of Japan on Friday.
The USGS said the massive quake struck off-shore 81 miles (130 km) east of Sendai in Honshu at a depth of 15.2 miles (24 km).
The USGS initially reported a 7.9 quake and later upgraded the magnitude to 8.8 and then to 8.9.
The earthquake caused many injuries, fires and a 13-foot (4-meter) tsunami along parts of the country's coastline that swept away houses, cars and boats, media and witnesses said.
There were several strong aftershocks and a warning of a 33-foot (10-meter) tsunami following the quake, which also caused buildings to shake violently in the capital Tokyo.
The USGS reported eight strong aftershocks, including a 6.8 quake on the mainland 41 miles (66 kms) northeast of Tokyo. (Reporting by Anthony Boadle)