New USGS number puts Japan quake at 4th largest

A monitor displays the seismological chart of the earthquake which hit Japan on March 11, 2011 at the Geozentrum geological science center in Hanover, central Germany. At least 40 people were killed and 39 missing in the massive 8.9-magnitude earthquake that hit Japan, unleashing huge tsunamis along its Pacific coast, police said. AFP PHOTO PETER STEFFEN GERMANY OUT (Photo credit should read PETER STEFFEN/AFP/Getty Images)

LOS ANGELES - The U.S. Geological Survey has upgraded the magnitude of Friday's deadly earthquake in Japan to 9.0

The move Monday comes after Japan's Meteorological Agency did the same. It's not unusual for scientists to tweak the magnitude of a giant quake after some number-crunching.

Complete coverage: Disaster in Japan

U.S. government scientists originally put the Japan quake at 8.9. The change to 9.0 means that the quake was about 1.5 times stronger than initially thought.

The Japan quake is now the fourth largest in the world since 1900 behind the 2004 magnitude-9.1 Sumatra quake.