Multi-Station GNSS Analysis of Crustal Deformation and Seismo-Ionospheric Anomalies Associated with the 2004 Sumatra-Andaman Earthquake

Multi-Station GNSS Analysis of Crustal Deformation and Seismo-Ionospheric Anomalies Associated with the 2004 Sumatra-Andaman Earthquake | 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 Multi-Station GNSS Analysis of Crustal Deformation and Seismo-Ionospheric Anomalies Associated with the 2004 Sumatra-Andaman Earthquake Atınç PIRTI, Ali Atıf PIRTI This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9505668/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 This study examines the 2004 Sumatra-Andaman earthquake (Mw9.1–9.3) Deformation of the Earth's crust and its ionospheric effects; SAMP conducts comprehensive surveys through a regional GNSS network consisting of SAMP, BAKO, NTUS, IISC, DGAR, and PIMO stations. Analyses using high-precision 1-Hz kinematic Precision Point Positioning (PPP) data revealed a dominant co-seismic horizontal displacement of ~ 26 ± 2 cm in the West-Southwest direction at the SAMP station, approximately 330 km from the epicenter. This value is in complete agreement with regional tectonic models. The originality of the study lies in its detection of a significant increase exceeding 20% ​​in ionospheric vertical total electron content (VTEC) five days before the main shock (December 21, 2004).While the anomaly in question exhibits spatial consistency across the network, detailed geomagnetic validation indicates that a G1 level geomagnetic storm occurred on this date (Kp ≈ 5) has revealed that it exists. This situation makes it difficult to directly identify the detected VTEC signal as a seismic preparation signal within the framework of the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC), and increases the risk of a "false positive". The findings confirm the strength of the 1-Hz kinematic PPP technique as a seismogeodetic tool in mega-earthquakes, while highlighting the critical importance of multi-station spatial coherence checks and geomagnetic noise elimination in verifying ionospheric precursors. 2004 Sumatra-Andaman earthquake Regional GNSS network Kinematic PPP VTEC anomaly G1 geomagnetic storm LAIC Spatial consistency analysis Full Text Additional Declarations No competing interests reported. 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. 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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-9505668","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":633250715,"identity":"609c3f70-0f07-472c-bd69-e060ab4bb812","order_by":0,"name":"Atınç PIRTI","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1klEQVRIiWNgGAWjYFACxgYGhgoGHj6GRCCDgZkIHWwgLWcYeNjgWtgIagFZ1AaiExiI08I/v7ntwc95h2XY2JObPzBUWCc2yPc+wKtF4hhju2HvtsM8bDwPGwwYzqQnNrCxG+C35hhjmzQjSItEYkMCY9thoBYCLpMHa5kD0XKA8R8RWgzAWhrAWhobgAzCWgyPJbZJ9hxLB/mlmSHhWLpxG1safi1yh48/k/hRY23Pz57++MOHGmvZfuZj+LVAQTOESmAgIiahoI5IdaNgFIyCUTAiAQC5ND65qRNO2AAAAABJRU5ErkJggg==","orcid":"","institution":"Yıldız Technical University","correspondingAuthor":true,"prefix":"","firstName":"Atınç","middleName":"","lastName":"PIRTI","suffix":""},{"id":633250716,"identity":"b433d2b2-091b-432d-b1ed-39ea157512b8","order_by":1,"name":"Ali Atıf PIRTI","email":"","orcid":"","institution":"Sisli terakki","correspondingAuthor":false,"prefix":"","firstName":"Ali","middleName":"Atıf","lastName":"PIRTI","suffix":""}],"badges":[],"createdAt":"2026-04-23 10:39:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9505668/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9505668/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108806828,"identity":"0090d393-c668-44b7-95bb-01bf2d1cbe14","added_by":"auto","created_at":"2026-05-08 15:29:34","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2654394,"visible":true,"origin":"","legend":"","description":"","filename":"articlesamp.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9505668/v1_covered_147532ea-5080-473e-b82e-bf88ee6066df.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Multi-Station GNSS Analysis of Crustal Deformation and Seismo-Ionospheric Anomalies Associated with the 2004 Sumatra-Andaman Earthquake","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"2004 Sumatra-Andaman earthquake, Regional GNSS network, Kinematic PPP, VTEC anomaly, G1 geomagnetic storm, LAIC, Spatial consistency analysis","lastPublishedDoi":"10.21203/rs.3.rs-9505668/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9505668/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study examines the 2004 Sumatra-Andaman earthquake (Mw9.1\u0026ndash;9.3) Deformation of the Earth's crust and its ionospheric effects; SAMP conducts comprehensive surveys through a regional GNSS network consisting of SAMP, BAKO, NTUS, IISC, DGAR, and PIMO stations. Analyses using high-precision 1-Hz kinematic Precision Point Positioning (PPP) data revealed a dominant co-seismic horizontal displacement of ~\u0026thinsp;26\u0026thinsp;\u0026plusmn;\u0026thinsp;2 cm in the West-Southwest direction at the SAMP station, approximately 330 km from the epicenter. This value is in complete agreement with regional tectonic models. The originality of the study lies in its detection of a significant increase exceeding 20% ​​in ionospheric vertical total electron content (VTEC) five days before the main shock (December 21, 2004).While the anomaly in question exhibits spatial consistency across the network, detailed geomagnetic validation indicates that a G1 level geomagnetic storm occurred on this date (Kp\u0026thinsp;\u0026asymp;\u0026thinsp;5) has revealed that it exists. This situation makes it difficult to directly identify the detected VTEC signal as a seismic preparation signal within the framework of the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC), and increases the risk of a \"false positive\". The findings confirm the strength of the 1-Hz kinematic PPP technique as a seismogeodetic tool in mega-earthquakes, while highlighting the critical importance of multi-station spatial coherence checks and geomagnetic noise elimination in verifying ionospheric precursors.\u003c/p\u003e","manuscriptTitle":"Multi-Station GNSS Analysis of Crustal Deformation and Seismo-Ionospheric Anomalies Associated with the 2004 Sumatra-Andaman Earthquake","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-08 01:32:27","doi":"10.21203/rs.3.rs-9505668/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"51681c04-7994-46dc-8f79-7c243a62c60d","owner":[],"postedDate":"May 8th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-10T18:33:42+00:00","index":12,"fulltext":""},{"type":"reviewerAgreed","content":"194005186765419386786522303451751822975","date":"2026-05-02T07:29:40+00:00","index":11,"fulltext":""},{"type":"reviewerAgreed","content":"297168240089275071622046575017010823235","date":"2026-04-29T15:18:38+00:00","index":10,"fulltext":""},{"type":"reviewerAgreed","content":"189607474012895728926490010543351113024","date":"2026-04-29T09:20:43+00:00","index":9,"fulltext":""},{"type":"reviewersInvited","content":"3","date":"2026-04-29T07:26:03+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T01:32:28+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-08 01:32:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9505668","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9505668","identity":"rs-9505668","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}