Japan’s Cabinet Office announced on Wednesday, August 20th, the latest survey results revealing that more than 520,000 people nationwide would need to evacuate a week in advance once the Japan Meteorological Agency issues the highest level “Huge Earthquake Warning” in the “Nankai Trough Earthquake Emergency Information.”
This marks the first official statistical estimation of the scale of potential evacuations, surpassing the approximately 470,000 individuals during the East Japan Great Earthquake (including the Fukushima nuclear disaster), indicating a highly severe potential impact. According to reports from Japanese media outlets like Jiji Press, the Nankai Trough Earthquake could trigger giant waves within minutes after the quake, raising concerns that many coastal areas may not have sufficient time to evacuate.
In order to mitigate risks, the Japanese government has mandated local municipalities to designate “pre-evacuation target areas” in advance, requiring residents to evacuate a week prior to the issuance of the “Huge Earthquake Warning.” The survey, conducted between June and August of this year, covered 29 prefectures designated as “Promotion Areas for Disaster Prevention Measures” and a total of 707 municipalities.
As of data from May, 130 municipalities in 16 prefectures across Japan have been designated as areas requiring mandatory pre-evacuation. The survey indicates that the total number of pre-evacuation targets exceeds 520,000 people, with over half (274,800 people) being elderly or individuals requiring special care. Among regions, Kochi Prefecture has the highest number of individuals, approximately 92,100, followed by Miyazaki Prefecture with around 79,900 people and Shizuoka Prefecture with roughly 70,200 people.
Furthermore, 195 municipalities have yet to designate pre-evacuation target areas, citing reasons such as being “under consideration” or “discussion not initiated.” The Cabinet Office has stated that it will urge these local governments to expedite assessments and decision-making processes.
The so-called “Nankai Trough Mega Earthquake” refers to earthquakes occurring in the plate boundary zone between the sea off Shizuoka Prefecture (Suruga Bay) and the sea off Miyazaki Prefecture (Hyuga-nada), potentially resulting in earthquakes of magnitude 8 to 9.
Based on the latest disaster loss assessment released by the Japanese government in March this year, under the worst-case scenario (such as occurring during late winter nights), the death toll from such earthquakes could potentially reach up to 298,000 individuals.
The “Nankai Trough Earthquake Emergency Information” has been operational since 2019, divided into three levels: the “Huge Earthquake Warning” requiring pre-evacuation, the “Huge Earthquake Caution” merely advising attention, and the “Post-earthquake Aftershock Alert.”
When the “Huge Earthquake Caution” was first issued in August last year, due to insufficient public awareness, some areas experienced confusion with incidents like the closure of beaches and cancellations of hotel bookings.