About the Off the coast of Hokkaido and Sanriku Subsequent Earthquake Advisory
"Off the coast of Hokkaido and Sanriku Subsequent Earthquake Advisory" warns of the risk of a megathrust earthquake occurring along the Japan and Chishima Trenches.
What is the Megaquakes along the Japan and Chishima Trenches
Large earthquakes have occurred along the Japan and Chishima Trenches, located east of Hokkaido and the Tohoku region, in 2003 and 2011. In the 2011 Tohoku Earthquake, a magnitude 7.3 earthquake occurred two days before the magnitude 9.0 earthquake.
If a megathrust earthquake were to occur in this region, it is expected that damage from earthquake tremors and tsunamis would occur over a wide area along the Pacific coast.
Source: Cabinet Office Megaquakes along the Japan and Chishima Trenches - Preparations -
What is the Off the coast of Hokkaido and Sanriku Subsequent Earthquake Advisory?
A massive earthquake is expected to occur off the Pacific coast of Hokkaido Prefecture, Aomori Prefecture, and Iwate Prefecture. If an earthquake of magnitude 7.0 or higher occurs in this area, the possibility of a subsequent megathrust earthquake occurring will be higher than usual, so an “Off the coast of Hokkaido and Sanriku Subsequent Earthquake Advisory” will be issued, calling for caution.
Based on past statistics, it is estimated that there is about a 1% chance that a megathrust earthquake will occur within seven days of this information being issued. Nevertheless, people are urged to review their evacuation routes and emergency preparations.
Notes Regarding the Information
- This information is intended to warn of the possibility of a series of large earthquakes occurring along the Japan and Chishima Trenches. It does not mean that an earthquake will definitely occur.
- Even if this information is not issued, there is a possibility that a large-scale earthquake may occur suddenly.
- Even after the government’s special advisories have ended, it does not mean that the risk of a large earthquake has disappeared.
