○Frequency of Nankai Trough Earthquakes

     The Nankai Trough earthquake is divided into the source areas of the Nankai, Tonankai, and Tokai earthquakes, from the west side of Shikoku to Shizuoka Prefecture. This earthquake occurred in a cycle of about 200-260 years from 684 to 1361, but since then it has become a 90-150 year cycle.

684: Hakuhou earthquake, M8

887: Ninna earthquake, M8 (203 years since the last earthquake)

1096/1099: Eichou/Kouwa earthquake, M8 (209 years since the last earthquake)

1361: Shouhei earthquake, M8 (265 years since the last earthquake)

1498: Meiou earthquake, M8.2 (137 years since the last earthquake)

1605: Keichou earthquake, M7.9 (107 years since the last earthquake)

1707: Houei earthquake, M8.6 (102 years since the last earthquake)

1854: Ansei Tokai earthquake and Ansei Nankai earthquake, M8.4 (147 years since the last earthquake)

1944: Tonankai earthquake, M7.9 (90 years since the last earthquake)

1946: Nankai earthquake, M8

Around 2044?: Nankai Trough earthquake, M8? (100 years since the last earthquake?)

    100 years after the 1944 Tonankai earthquake is 2044, but the Tokai earthquake, located to its east, has not occurred for over 160 years since 1854, so it is said that it could occur at any time. This could trigger earthquakes in the Nankai and Tonankai areas as well. Japan is a country where a major earthquake occurs in a 100-year cycle, and many other earthquakes occur in between, bringing tsunamis. We must build cities on this premise. If we build a country where economic activities and population are concentrated in cities like Tokyo and Osaka, there is a risk that economic activities will be paralyzed by a major earthquake that comes about once every 100 years. We can't eliminate natural disasters, but Prout Village is a system where we don't build cities, keep disaster damage to a minimum, and can quickly recover. The same applies worldwide, with the premise that no cities are built within 10km inland from coasts where there is a risk of tsunamis.