The Japan Meteorological Agency on Sunday upgraded the magnitude of Friday's catastrophic earthquake to 9.0, making it the world's fourth-strongest in more than a century.
The Japan Meteorological Agency on Sunday upgraded the magnitude of Friday's catastrophic earthquake to 9.0, making it the world's fourth-strongest in more than a century.
The agency had earlier put the magnitude of the quake off the coast of Miyagi Prefecture, northern Japan, at 8.8.
A 0.2 increase in magnitude translates into twice the amount of energy generated.
The energy released by Friday's quake was about 45 times that of the Great Kanto Earthquake that killed some 140,000 people in the Tokyo area in 1923, and about 1,450 times that of the Great Hanshin Earthquake that leveled much of Kobe in 1995 and left more than 6,400 people dead.
Other major earthquakes that have hit since 1900 are as follows: In 1952, a magnitude 9.0 earthquake struck Kamchatka. A magnitude 9.5 quake devastated Chile in 1960, and a 1964 quake in Alaska had a magnitude of 9.2. The 2004 quake off Sumatra, Indonesia, that triggered a tsunami that claimed many tens of thousands of lives had a magnitude of 9.1.
The Japan Meteorological Agency also said Sunday there was a 70-percent probability of an aftershock with a magnitude of at least 7 occurring within three days of 10 a.m. Sunday.
The agency said that aftershocks from Friday's magnitude 9.0 earthquake had been occurring in an area of roughly 500 kilometers in length and about 200 kilometers in breadth from off the coast of Iwate Prefecture to off the coast of Ibaraki Prefecture.
The area corresponds to the region where the focus of Friday's earthquake is believed to have been. The large number of aftershocks demonstrates a very active seismic situation, based on past earthquake examples.
Because of the extensive area in which aftershocks have been recorded, the intensity based on the Japanese scale could differ according to where they occur even if the magnitudes of the aftershocks were similar, agency officials said.
According to police, 977 people in Iwate, Miyagi, Fukushima, Tokyo and eight other prefectures were confirmed dead as of 3:00 p.m. Sunday, while 739 people were reported missing.
Naoto Takeuchi, head of the Miyagi prefectural police, said Sunday that the number of casualties in that prefecture alone would likely top 10,000.