The powerful earthquake that rattled the Tohoku region Tuesday was not the big temblor predicted to strike the area within the next 30 years, the government's Earthquake Research Committee concluded Wednesday.
"The earthquake this time was different from the one we have been simulating," a committee member said Tuesday. "The expected area of the simulated quake's focus is much broader and this time the (Earth's crust) destruction only took place in part of the area."
The government said in January there is a 99 percent chance that a quake of about magnitude 7.5 would hit the area within 30 years. The committee said it has no immediate plan to revise the prediction.
Quakes of magnitude 7 or above have occurred on average once every 37 years at a fault line off the coast of Miyagi Prefecture. Nine quakes of magnitude 6.4 or above, including the latest one, have occurred along the Miyagi coast since 1933.
Tuesday's temblor of magnitude 7.2 and its aftershocks were mostly centered south of a 1978 Miyagi earthquake.
The tsunamis that resulted from the latest quake also originated south of those in 1978 and were smaller in scale, according to the committee.
The 1978 quake, of magnitude 7.4, killed 28 people and injured more than 10,000 in Sendai and the surrounding area.
The committee has said the next major earthquake in Miyagi is likely to hit by 2020.
Sixty-one people were injured in Tuesday's quake, which affected a large area of northeastern Honshu, including Miyagi, Iwate, Fukushima, Saitama and Tokyo prefectures.