Key Facts
• 2016 Kumamoto Earthquake damaged over 190,000 homes.
• July 30, 2025: M8.8 earthquake struck off Kamchatka Peninsula.
• Nankai Trough Earthquake (M9) has an 80% chance of occurring within 30 years.
• Osaka’s Uemachi Fault Zone spans 42 km, with potential M7.5 earthquakes.
• Osaka Bay Fault Zone could impact Kobe with M7.5 earthquakes.
• Fukuoka’s Kego Fault Zone (55 km) may trigger M7.2 earthquakes.
• Kumamoto’s Hinagu Fault Zone (81 km) could cause M8.0 earthquakes.
• Sendai’s Nagamachi-Rifu Fault Zone (21–40 km) may result in M7.5 earthquakes.
• Nagoya’s Yoro-Kuwana-Yokkaichi Fault Zone (60 km) could produce M8 earthquakes.
• Itoigawa-Shizuoka Fault Zone (158 km) spans Nagano and Yamanashi, with M7.4–7.7 risks.
• Tokyo’s Tachikawa Fault Zone (33 km) may trigger M7.4 earthquakes.
• Izu Peninsula’s Shirahama and Ito Offshore Faults (X Rank) require further study.
• Recent earthquakes: Kagoshima (M6), Hyuga-nada (M5), Aizu (M5), Nagano (M5).
Summary
Japan’s urban centers face significant risks from active fault zones, with potential for devastating earthquakes. The Uemachi Fault Zone in Osaka and the Kego Fault Zone in Fukuoka are among the most dangerous, capable of producing M7.5 and M7.2 earthquakes, respectively. Sendai’s Nagamachi-Rifu Fault Zone and Nagoya’s Yoro-Kuwana-Yokkaichi Fault Zone also pose threats, with estimated magnitudes of M7.5 and M8.0. The Itoigawa-Shizuoka Fault Zone, spanning 158 km, is one of the longest and most studied, with risks of M7.4–7.7 earthquakes. Tokyo’s Tachikawa Fault Zone and Izu Peninsula’s Shirahama and Ito Offshore Faults add to the concerns. Recent seismic activity in Kagoshima, Hyuga-nada, Aizu, and Nagano highlights the urgency of preparedness. Authorities and experts emphasize the need for awareness and disaster readiness in these densely populated areas.
