A new evacuation plan outlined in preparation for a possible Mt. Fuji eruption would displace an estimated 1.2 million people. Two-thirds of the number, or around 750,000 people, come from the prefectures of Shizuoka and Yamanashi, while another 470,000 currently reside in Kanagawa.
A UNESCO World Heritage site, 3,776-meter Mt. Fuji is an active volcano that has erupted many times in the past. It is situated between Shizuoka and Yamanashi prefectures, and also near Kanagawa. A hazard map for the volcano was prepared in 2004 and showed areas which are at high risk of being affected by volcanic ash. Notable areas in the three prefectures are populated with wooden houses, in which locals reside. Should the volcano erupt, these houses are at risk of being crushed under heavy volcanic ash that gets its weight after absorbing rain in the atmosphere. An estimated 406,000 people from Kanagawa, 62,000 in Shizuoka, and 1,000 in Yamanashi would be affected by heavy ash measuring 30 centimeters or more.
A bigger number of around 8.85 million living in other areas of the three prefectures may have their health at risk with at least 2 cm of volcanic ash. While the direct effect of volcanic ash on the population varies on other factors such as wind direction, the Meteorological Agency may still issue a strict warning based on its observations and simulations. Meanwhile, an evacuation plan for when lava flows shows the area within the volcano divided into five parts, and dependent on the time the lava is expected to reach their towns. The current evacuation plan drawn does not include volcanic eruptions, which may happen after a major earthquake comes from the Nankai Trough in the Pacific Ocean.