Geodynamics of forearc topography and strain linked with giant earthquake rupture area

Geodynamics of forearc topography and strain linked with giant earthquake rupture area | 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 Geodynamics of forearc topography and strain linked with giant earthquake rupture area Wouter P. Schellart, Vincent Strak, Kai Xue, Francisco Bolrão, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8231702/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The forearc topography at several subduction zones on Earth is complex, involving a ridge and depression (e.g. Alaska, Chile, Cascadia) in between trench and magmatic arc. The ridge and depression show trench-normal extension and shortening, respectively. Here we propose that forearc topography and strain result from subduction interface suction forces that bend the overriding plate, with shortening in the depression accommodating lithospheric inner-bend deviatoric compression and extension in the ridge accommodating outer-bend deviatoric tension. We present a four-dimensional geodynamic subduction experiment that demonstrates the spatial and temporal correlation between forearc depression and shortening, and between forearc ridge and extension. Maximum topographic curvature spatially corresponds with maximum surface strain, substantiating our mechanical explanation for the anomalous topography and strain at several subduction zones. Our experiment provides new insight into the largest recorded earthquakes (1960 Valdivia, 1964 Alaska), characterised by rupture areas with an extreme trench-parallel extent, overlain by forearc domains with pronounced ridge-depression topography. Our experiment predicts high tensile deviatoric normal stresses on the subduction zone plate boundary interface that generated these earthquakes. We propose a conceptual model in which such stresses facilitate lateral rupture growth. Our global compilation of subduction zone rupture extent and proxy for interface stress corroborates this. Geophysics Geology subduction overriding plate forearc topography strain geodynamic model subduction interface stress earthquake rupture area Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8231702","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":552361200,"identity":"71b1cecc-b94e-4b38-863f-7c1040ae7da7","order_by":0,"name":"Wouter P. 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