About the Nankai Trough Earthquake Extra Information
What is the Nankai Trough Earthquake?
This is a large-scale earthquake with its hypocenter at the plate boundary (Nankai Trough) along the Pacific coast from Shizuoka Prefecture to Miyazaki Prefecture. In the past, these have occurred repeatedly at intervals of 100 to 150 years.
Approximately 80 years have passed since the last earthquake, and it is believed that the next earthquake could occur at any time.
Large tremors and tsunami damage are expected over a wide area from Kanto to Kyushu.
Source: Cabinet Office Nankai Trough Earthquake - Preparations -
What is the Nankai Trough Earthquake Extra Information?
This information is intended to warn people of the possibility of large tremors and tsunamis caused by a large-scale earthquake that may occur in the future along the Nankai Trough.
This is not a warning that an earthquake will definitely occur during the period when this information is issued.
It is issued, for example, when an unusual phenomenon is observed along the Nankai Trough and an investigation begins into its possible relation to a Nankai Trough earthquake, or when the likelihood of an earthquake is assessed to be relatively higher than usual.
| Under Analysis | If an investigation is initiated, or is ongoing, into the possible relationship between unusual phenomena observed along the Nankai Trough and a Nankai Trough earthquake |
|---|---|
| Megathrust Earthquake Alert | If it is assessed that an earthquake of magnitude 8.0 or greater has occurred at the plate boundary |
| Megathrust Earthquake Attention | If it is assessed that an earthquake of magnitude 7.0 or greater has occurred at a plate boundary, etc. |
| Analysis Complete | If it is assessed that the situation does not correspond to either a "Megathrust Earthquake Alert" or "Megathrust Earthquake Attention" |
If a "Megathrust Earthquake Alert" or "Megathrust Earthquake Attention" is issued, you will be required to take disaster-prevention actions.
Remain calm and follow the instructions provided by reliable sources such as the government or your local authorities.
Notes Regarding the Information
- This information is intended to warn of the possibility of a large earthquake occurring along the Nankai Trough. 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.
