Three-dimensional resistivity structure in the Nankai Trough off Kumano inferred using marine magnetotelluric investigations

Three-dimensional resistivity structure in the Nankai Trough off Kumano inferred using marine magnetotelluric investigations | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Three-dimensional resistivity structure in the Nankai Trough off Kumano inferred using marine magnetotelluric investigations Manaka Kuroda, Hiroshi Ichihara, Tada-nori Goto, Takafumi Kasaya, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6137918/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 26 Dec, 2025 Read the published version in Earth, Planets and Space → Version 1 posted 5 You are reading this latest preprint version Abstract Megathrust and slow earthquakes are known to occur in the area off Kumano, along the eastern part of the Nankai Trough, Japan. Pore fluids along the fault surface play an important role in earthquake occurrence, but the detailed fluid distribution remains unknown. In this study, based on seafloor electromagnetic field observations, we estimated the three-dimensional resistivity structure, which reflects the fluid distribution off-Kumano. The optimal three-dimensional resistivity model showed a low resistivity layer at shallow depths below the seafloor and did not indicate any major resistivity variations parallel to the Nankai Trough. The low resistivity layer matches geological features observed in seismic reflection surveys, including forearc basin fill, the frontal prism, and underthrust sediments. Along the plate boundary (décollement), the resistivity increased markedly with increasing depth. Comparison with slow earthquakes along the plate boundary reveals that shallow very low-frequency earthquakes and shallow slow slip events do not occur in the shallow, low resistivity layers, but at moderate depths where the resistivity along the plate boundary is moderate. Furthermore, the area of coseismic slip during the 1944 Tonankai earthquake was characterized by greater resistivity than the slow earthquake epicentral area. These findings indicate that the pore fluid distribution along the plate boundary may influence earthquake occurrence and type. Off Kumano area Nankai Trough Magnetotelluric Resistivity OBEM Full Text Supplementary Files SupplementarymaterialsEPS3Doffkumano.docx graphicalabstractv2.png Cite Share Download PDF Status: Published Journal Publication published 26 Dec, 2025 Read the published version in Earth, Planets and Space → Version 1 posted Reviewers agreed at journal 27 Mar, 2025 Reviewers invited by journal 24 Mar, 2025 Editor assigned by journal 20 Mar, 2025 First submitted to journal 13 Mar, 2025 Editorial decision: Major Revision 08 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6137918","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":432949321,"identity":"ed8bcace-95da-4956-8f57-a47236a473d8","order_by":0,"name":"Manaka 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