A government panel will review its forecasts for earthquakes along the Pacific coast of eastern Japan after admitting it had erred in not foreseeing the possibility of the magnitude 9.0 Great East Japan Earthquake.
A government panel will review its forecasts for earthquakes along the Pacific coast of eastern Japan after admitting it had erred in not foreseeing the possibility of the magnitude 9.0 Great East Japan Earthquake.
Earthquake Research Committee Chairman Katsuyuki Abe, a professor emeritus at the University of Tokyo, said his committee will review earthquake forecasts for areas from off the Sanriku region to off the Boso region in Chiba Prefecture.
"We had thought that a magnitude 9.0 earthquake will not strike Japan although it occurred elsewhere in the world," Abe said. "We were bound by academic paradigms. We have much to reflect on."
Sanriku refers to the coastal region of Aomori, Iwate and Miyagi prefectures.
The Earthquake Research Committee has forecast the probabilities and scales of earthquakes for each of eight presumed focal areas along the coast of Aomori to Chiba prefectures.
The only exception it has looked into was the possibility that two of these areas off Miyagi Prefecture may combine to cause an earthquake with a magnitude of around 8.
However, the Great East Japan Earthquake was caused when six of the eight areas moved simultaneously.
At a meeting on Monday, committee members concluded that the earthquake's focal area, which stretched from off the Sanriku region in the north to off Ibaraki Prefecture in the south, was beyond its forecasts.
The committee had begun to consider whether it needed to review forecasts after it became known that the Jogan Earthquake of 869 triggered a massive tsunami in the Tohoku region. But the Great East Japan Earthquake struck before it reached any decision.
While the committee had mainly examined whether past earthquakes would occur again, members will also discuss whether these methods are appropriate.
Abe declined to comment on whether the committee will review forecasts for the Tokai, Tonankai and Nankai earthquakes expected along the Nankai Trough, which stretches off the Tokai region to off the island of Shikoku.
Currently, the magnitude of the Tonankai Earthquake is forecast at around 8.1 and that of the Nankai Earthquake is forecast at around 8.4. If the two earthquakes strike together, the estimated magnitude would be around 8.5.
Meanwhile, the committee said caution is needed because an aftershock of the Great East Japan Earthquake with a magnitude in excess of 7 can occur.
It also said that earthquakes with a magnitude of 7 to 8 can occur around the focal area of the Great East Japan Earthquake.