Seismic Detection of a 600-km Solid Inner Core on Mars

Seismic Detection of a 600-km Solid Inner Core on Mars | 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 Physical Sciences - Article Seismic Detection of a 600-km Solid Inner Core on Mars Daoyuan Sun, Huixing Bi, Ningyu Sun, Zhu Mao, Mingwei Dai, Douglas Hemingway This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4423842/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Sep, 2025 Read the published version in Nature → Version 1 posted You are reading this latest preprint version Abstract For rocky planets, the presence of a solid inner core has strong implications for the composition and thermal evolution of the core and for the planet's magnetic history (refs.1-3). On Mars, geophysical observations have confirmed that the core is at least partially liquid (refs.4-7), but it has been unclear whether any part of the core is solid. Here we show from analysis of seismic data acquired by the InSight mission that Mars has a solid inner core. We identify two seismic phases, the deep core-transiting phase, PKKP, and the inner core boundary reflecting phase, PKiKP, indicative of the inner core. Our inversions constrain the radius of the Martian inner core to ~610±50 km, with a compressional velocity jump of ~30% across the inner core boundary. These inner core properties imply a concentration of distinct light elements, supporting inner core crystallization following a “snowing-core” model (ref.8), indicating a relatively low temperature on Mars. This finding provides an anchor point for understanding the thermal and chemical state of Mars. Additionally, the relationship between inner core formation and the Martian magnetic field evolution could offer critical insights into dynamo generation across planetary bodies. Physical sciences/Astronomy and planetary science/Planetary science Physical sciences/Astronomy and planetary science Physical sciences/Astronomy and planetary science/Planetary science/Seismology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SIGuide.docx SIGuide MarsInnerCoreSupplementMaterialsAB.pdf Supplementary Information A and B Cite Share Download PDF Status: Published Journal Publication published 03 Sep, 2025 Read the published version in Nature → 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. 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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-4423842","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":316514526,"identity":"6eabc07b-5120-4115-8131-50e7d53e69c4","order_by":0,"name":"Daoyuan 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