更新日：2025年4月1日

The Nankai Trough Earthquake Extra Information

The Nankai Trough Earthquake Extra Information

Overview

On the 31st of May 2019, there were changes to the country via the "Nankai Trough  Earthquake Operation Plan". The Japanese Meteorological Agency (JMA) started to make use of the "Nankai Trough Earthquake Extra Information" (Hereafter "Extra Information").

Making use of the Nankai Trough Earthquake Extra Information

In accordance to the extra information announced, if a 6.8 Magnitude (Hereafter "M") or above earthquake occurs or there is an abnormal amount of activity sensed in the tectonic plates in the Nankai Trough area, the state will begin its investigation into this, and the JMA will announce their Extra Information (under investigation). Depending on the results of the research found in Japan's "Nankai Trough Assessment Committee Meeting" they will announce one of the following "Major Earthquake Warning", "Major Earthquake Advisory" or "Investigation Over".

Classification of Extra Information

In the case a Major Earthquake Warning is necessary *If an extremely strong earthquake, registering over M8.0 occurs in the Nankai Trough area

Subject	Keyword	Conditions for Each Announcement to be Released
Nankai Trough Earthquake Extra Information (Nankai torofu jishin kakuji jōhō)	Under Investigation (chōsa chū)	〇Investigations into the irregularities observed around the Nankai Trough plates and if they're linked to a Major Earthquake.  Announcements will state if investigations of the plates have started or if they are contining form a previous investigation.
	Major Earthquake Warning (kyodai jishin keikai)
	Major Earthquake Advisory (kyodai jishin chūi)	In the case a Major Earthquake Advisory is necessary *If a strong earthquake, over M7.0 but less than M8.0 occurs in the area or there is an abnormal amount of movement detected in the tectonic plates around the Nankai Trough.
	Investigation Over (chōsa shūryo)	In the case that the phenomenon does not fall under either "Major Earthquake Warning" nor "Major Earthquake Advisory" categories.
Commentary information related to the Nankai Trough Earthquake	〇 Following results from investigations of irregular phenomenon that were observed from the quake, announcements on the current situation will be made. 〇 Announcements on the results from investigations from the regular meeting of "Nankai Trough Area Major Earthquake Evaluation Committee" (Excluding the announcement of extra plans)

Important points regarding what you should do

1. Obtain correct information

Check the television or radio.
Also check information from City Hall and independent disaster prevention groups.

2. Checking your Emergency Kit

Please check that your kit includes all the items required in preparation for an earthquake. 

3. Confirming Contact Methods

Please confirm evacuation points and how you will contact your family members in the event that power outages caused by earthquakes render you unable to reach their school or places of work. 

4. Preparing Your Home

Move items from high places and ensure a clear path leading to the front door. 

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