{"id":268,"date":"2025-06-26T11:17:39","date_gmt":"2025-06-26T09:17:39","guid":{"rendered":"https:\/\/nature-o.net\/?p=268"},"modified":"2025-06-26T11:17:40","modified_gmt":"2025-06-26T09:17:40","slug":"can-a-megaquake-strike-japan-soon-lyubushins-predictions-for-the-nankai-trough","status":"publish","type":"post","link":"https:\/\/nature-o.net\/?p=268","title":{"rendered":"Can a Megaquake Strike Japan Soon? Lyubushin\u2019s Predictions for the Nankai Trough"},"content":{"rendered":"\n

Russian geophysicist Alexey A. Lyubushin<\/strong> has developed a novel method to evaluate long-term seismic hazards using multifractal analysis<\/strong> of continuous low-frequency microseismic noise<\/strong>. His work is especially relevant for Japan \u2014 one of the world\u2019s most seismically active regions. Among his key concerns is the growing risk of a megathrust earthquake<\/strong> along the Nankai Trough<\/strong>, a known subduction zone south of Honshu.<\/p>\n\n\n\n

\n\n\n\n

How Lyubushin’s Method Works<\/h3>\n\n\n\n

Lyubushin analyzes long-term data from Japan\u2019s F-net seismic network<\/strong>, looking for changes in:<\/p>\n\n\n\n

    \n
  • Noise variance width<\/strong><\/li>\n\n\n\n
  • Predictability indices<\/strong><\/li>\n\n\n\n
  • Spatial synchronization of microseisms<\/strong><\/li>\n<\/ul>\n\n\n\n

    From 1997 to 2011, his findings showed a clear trend toward synchronization<\/strong>, a possible early warning signal of critical stress accumulation<\/strong> in the tectonic system.<\/p>\n\n\n\n

    \n\n\n\n

    Rising Risk of a Nankai Megathrust Earthquake<\/h3>\n\n\n\n

    The Nankai Trough<\/strong> \u2014 stretching from the Tokai region to Kyushu \u2014 is one of the most closely watched fault systems on Earth. It has a historical pattern of massive quakes<\/strong> every 90\u2013150 years, and segments often rupture in pairs<\/strong> (Tokai + Tonankai or Tonankai + Nankai) within a short span.<\/p>\n\n\n\n

    According to Lyubushin:<\/p>\n\n\n\n

      \n
    • By mid\u20112010<\/strong>, the Japanese seismic system showed statistical signs of entering a \u201ccritical state.\u201d<\/strong><\/li>\n\n\n\n
    • He believes this is particularly alarming for the Nankai Trough<\/strong>, where tectonic compression has been increasing steadily.<\/strong><\/li>\n\n\n\n
    • His probabilistic forecast<\/strong> suggests a very high likelihood<\/strong> of a megathrust earthquake (M8\u20139+)<\/strong> occurring in the next few years<\/strong>, potentially affecting central to southern Japan<\/strong>.<\/li>\n<\/ul>\n\n\n\n

      This aligns with Japanese government estimates, which predict up to 320,000 casualties<\/strong> and massive infrastructural damage in the event of a Nankai rupture.<\/p>\n\n\n\n

      \n\n\n\n

      What Makes the Nankai Trough So Dangerous?<\/h3>\n\n\n\n
        \n
      • It marks the convergent boundary<\/strong> between the Philippine Sea Plate<\/strong> and the Eurasian Plate<\/strong>.<\/li>\n\n\n\n
      • The entire region is densely populated<\/strong>, with megacities like Osaka<\/strong>, Nagoya<\/strong>, and Tokyo<\/strong> in the hazard zone.<\/li>\n\n\n\n
      • Past events (e.g., 1944 Tonankai M8.1, 1946 Nankai M8.4) support the recurrence theory<\/strong>.<\/li>\n\n\n\n
      • The slow-slip events<\/strong> recently observed in the Tokai area may be early warning indicators.<\/li>\n<\/ul>\n\n\n\n
        \n\n\n\n

        Can We Be Ready?<\/h3>\n\n\n\n

        Lyubushin\u2019s method doesn\u2019t predict an exact date \u2014 but it sharpens our understanding of when tectonic conditions become highly unstable<\/strong>. Japan is actively:<\/p>\n\n\n\n

          \n
        • Updating early warning systems<\/strong>,<\/li>\n\n\n\n
        • Preparing tsunami evacuation infrastructure<\/strong>,<\/li>\n\n\n\n
        • Reinforcing buildings and critical lifelines<\/strong>,<\/li>\n\n\n\n
        • Conducting nationwide drills<\/strong> for the “Nankai Trough Emergency Plan”.<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n

          Glossary<\/h2>\n\n\n\n
            \n
          • Nankai Trough<\/em><\/strong>: A subduction zone south of Japan, prone to megathrust quakes.<\/li>\n\n\n\n
          • Megathrust Earthquake<\/em><\/strong>: A powerful earthquake occurring at subduction zones, often above M8.<\/li>\n\n\n\n
          • Microseismic noise<\/em><\/strong>: Background seismic vibrations used for long-term monitoring.<\/li>\n\n\n\n
          • Multifractal analysis<\/em><\/strong>: A statistical method analyzing complex, scale-variable structures.<\/li>\n\n\n\n
          • Slow-slip event<\/em><\/strong>: A gradual fault movement that can signal stress buildup.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

            Russian geophysicist Alexey A. Lyubushin has developed a novel method to evaluate long-term seismic hazards using multifractal analysis of continuous low-frequency microseismic noise. His work is especially relevant for Japan…<\/p>\n","protected":false},"author":2,"featured_media":269,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_sitemap_exclude":false,"_sitemap_priority":"","_sitemap_frequency":"","footnotes":""},"categories":[51,48,44],"tags":[],"_links":{"self":[{"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/posts\/268"}],"collection":[{"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nature-o.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=268"}],"version-history":[{"count":1,"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/posts\/268\/revisions"}],"predecessor-version":[{"id":270,"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/posts\/268\/revisions\/270"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nature-o.net\/index.php?rest_route=\/wp\/v2\/media\/269"}],"wp:attachment":[{"href":"https:\/\/nature-o.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=268"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nature-o.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=268"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nature-o.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=268"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}