(Subscription Only) Title: Researcher: Japan should prepare for worst-case magnitude-10 earthquake
Author: SHIGEKO SEGAWA
Date: November 23, 2012
Japan should be prepared for the possibility of a magnitude-10 earthquake, although the chances of a temblor that size are slim, a seismologist said.
If a temblor of such a scale should strike, the underground rupture would continue for 20 minutes to an hour, meaning tsunami could hit coasts before the shaking subsides.
If a 3,000-kilometer stretch from the Japan Trench to the Kuril-Kamchatka Trench along the Pacific Ring of Fire has a slip of 60 meters, that would constitute a magnitude-10 earthquake, [professor Toru Matsuzawa of Tohoku University] said.
The energy of a magnitude-11 quake, 30 times more powerful than a magnitude-10 temblor, would be equivalent to that of the asteroid impact that is believed to have caused the extinction of the dinosaurs 65.5 million years ago. Such a quake would cause a shift extending more than 20,000 kilometers. Matsuzawa concluded that consideration would not be needed for such an earthquake.
Title: Expert says maximum M10 earthquake possible
Source: NHK WORLD English
Date: Nov. 22, 2012
A magnitude-10 quake would be 32 times more powerful than the 9.0 earthquake that hit northeastern Japan in March last year. [...]
A magnitude-10 quake would occur, for example, if an 8,800-kilometer fault along a northern Pacific Rim trench shifts 20 meters.
Matsuzawa says such an earthquake would result in tremors lasting 20 minutes to one hour, and trigger days of tsunamis.
Matsuzawa stresses he’s not saying a magnitude-10 quake would definitely occur. But he notes that Japan was hit by a magnitude-9 earthquake when it had been expecting a maximum magnitude-8, so people should be aware of what could happen.
Published: November 23rd, 2012 at 10:26 am ET