A Novel Framework for Gravity Anomaly Decomposition: Iterative Polynomial Fitting and K-Means Clustering with Application to the Zagros Collision Zone

A Novel Framework for Gravity Anomaly Decomposition: Iterative Polynomial Fitting and K-Means Clustering with Application to the Zagros Collision Zone | 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 A Novel Framework for Gravity Anomaly Decomposition: Iterative Polynomial Fitting and K-Means Clustering with Application to the Zagros Collision Zone Ako Alipour, Khalil Motaghi, Zahra Mousavi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7527448/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 8 You are reading this latest preprint version Abstract This study presents an approach that integrates iterative polynomial fitting, dynamic weighting based on regional effects, K-means clustering, and redistribution of long-wavelength anomalies to isolate subsurface features. A high-degree polynomial is initially fitted to gravity data to capture the overall trend, followed by iterative reduction of the polynomial degree to highlight residual components. Tikhonov regularization prevents overfitting, while dynamic weighting adjusts residuals according to regional effects. K-means clustering classifies residuals into features such as sediment-basement interfaces, crustal roots, and the lithosphere-asthenosphere boundary, with clusters selected based on frequency characteristics and statistical robustness. The final anomaly for each feature is reconstructed by averaging cluster residuals, and remaining long-wavelength anomalies are redistributed to represent deeper layers accurately. The method, termed Iterative Polynomial Decomposition and K-means Clustering, is validated on three synthetic models simulating continental, oceanic, and rift environments. Results show improved decomposed layers, minimizing edge effects, dislocation, and over-smoothing. Applied to the Zagros collision zone, the crustal gravity response aligns with prior studies, e.g., a negative anomaly in the Zagros foreland basin (thick sediments) and a positive anomaly beneath the South Caspian Basin (dense lithosphere). Comparisons with seismic Moho models reveal deep Moho signatures in eastern Alborz and Kopeh Dagh, but discrepancies in northwestern Iran and Talesh suggest shallower gravity-derived Moho response. Across the Main Zagros Fault, gravity and seismic responses diverge, reflecting lateral density variations, partial melting, and method-specific sensitivities. In stable regions, gravity and seismic models converge, whereas in active collision zones, complex crustal gradients lead to differences in interpretations. Iterative Polynomial Decomposition K-Means Clustering Gravity Anomaly Analysis Tikhonov Regularization Zagros Collision Zone Crustal Structure Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 11 May, 2026 Reviews received at journal 12 Feb, 2026 Reviewers agreed at journal 05 Feb, 2026 Reviewers agreed at journal 03 Feb, 2026 Reviewers invited by journal 03 Feb, 2026 Editor assigned by journal 03 Sep, 2025 Submission checks completed at journal 03 Sep, 2025 First submitted to journal 03 Sep, 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-7527448","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":584814208,"identity":"f22feebb-c7de-435f-abfd-7cd4373d3fec","order_by":0,"name":"Ako Alipour","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBAC9gYgkfDDRo6fgYGNOC08B4DEw540Y8kGUrQwPmA7lGhwgGgt7GefPUjgOZBgfCP52YMPFQzy/GIHCGjhSTc3SLC4k2d2I83ccMYZBsOZsxPwa7FnSGOTSOB5Vmx2I8FMmreNIcHgNgEtPPzPgFrYDidunpH+jUgtEmkQLRskcoi1RQJoSyIwkCXOvCmTnHFGgrBfePjT2CR/gKKyPX2bxIcKG3l+aQJaEEAArFKCWOUgwH+AFNWjYBSMglEwkgAA/dtAVg698hsAAAAASUVORK5CYII=","orcid":"","institution":"IASBS","correspondingAuthor":true,"prefix":"","firstName":"Ako","middleName":"","lastName":"Alipour","suffix":""},{"id":584814209,"identity":"43761f49-9331-4877-9d20-ff624617c433","order_by":1,"name":"Khalil Motaghi","email":"","orcid":"","institution":"IASBS","correspondingAuthor":false,"prefix":"","firstName":"Khalil","middleName":"","lastName":"Motaghi","suffix":""},{"id":584814210,"identity":"5854f068-f744-4ee4-ba7f-44f856a43339","order_by":2,"name":"Zahra Mousavi","email":"","orcid":"","institution":"IASBS","correspondingAuthor":false,"prefix":"","firstName":"Zahra","middleName":"","lastName":"Mousavi","suffix":""}],"badges":[],"createdAt":"2025-09-03 13:23:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7527448/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7527448/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101881133,"identity":"0b98c96a-636f-4624-937c-bbc9c1dbc665","added_by":"auto","created_at":"2026-02-04 15:10:06","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7798709,"visible":true,"origin":"","legend":"","description":"","filename":"Polynomialclustering.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7527448/v1_covered_85cf9d54-9c83-4aa3-8687-c0f58d4c5fe7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Novel Framework for Gravity Anomaly Decomposition: Iterative Polynomial Fitting and K-Means Clustering with Application to the Zagros Collision Zone","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pure-and-applied-geophysics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"paag","sideBox":"Learn more about [Pure and Applied Geophysics](https://www.springer.com/journal/24)","snPcode":"24","submissionUrl":"https://submission.nature.com/new-submission/24/3","title":"Pure and Applied Geophysics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Iterative Polynomial Decomposition, K-Means Clustering, Gravity Anomaly Analysis, Tikhonov Regularization, Zagros Collision Zone, Crustal Structure","lastPublishedDoi":"10.21203/rs.3.rs-7527448/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7527448/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents an approach that integrates iterative polynomial fitting, dynamic weighting based on regional effects, K-means clustering, and redistribution of long-wavelength anomalies to isolate subsurface features. 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