New 3-D Combined Inversion Scheme Using Response Functions Free From Galvanic Distortion

New 3-D Combined Inversion Scheme Using Response Functions Free From Galvanic Distortion | 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 New 3-D Combined Inversion Scheme Using Response Functions Free From Galvanic Distortion Yoshiya Usui, Makoto Uyeshima This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-798901/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 combined inversion using distortion-free response functions is an effective approach to robustly estimate the 3-D electrical resistivity structure against the distortions caused by near-surface resistivity anomalies. However, previous combined inversion analyses have presented a significant dependency of the inversion results on initial and prior models. Therefore, in this study, we evaluated the effectiveness of the following two new types of 3-D combined inversion using distortion-free response functions: one uses the phase tensor and the vertical and inter-station horizontal magnetic transfer functions, while the other uses the Network-MT response functions, in addition to the former. Because long dipoles are used, the Network-MT response function is negligibly affected by galvanic distortion. To access the combined inversion approach, we developed a novel 3-D inversion scheme combining the response functions of the usual magnetotelluric measurements and the Network-MT response function. The synthetic inversion analysis demonstrated that both of the proposed combined inversions can recover the characteristic resistivity distributions of the target model without a significant dependence on the initial models, at least in the shallow part. These results demonstrate that the combined inversions using only distortion-free response functions have the potential to estimate subsurface resistivity more robustly than what was previously thought. Furthermore, we confirmed that the combined inversion using the Network-MT response function can make the resultant resistivity structure closer to the actual one and enhance the stability of the inversion. This result suggests that the combined use of the Network-MT response function is the preferred approach. Geology Planetary Science magnetotelluric inversion Network-MT method galvanic distortion finite element method phase tensor magnetic transfer function tetrahedral mesh Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Full Text Supplementary Files GraphicalAbstract.jpg supportinginformation.docx 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-798901","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":47110460,"identity":"7dc8f076-a9ca-489c-b1cc-3598b4deeb00","order_by":0,"name":"Yoshiya Usui","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYLCChAoGBjYoEyrEQ0jLGaiWA0RrYWyDMhBa8ACDG+nPJB7Os8nnY+AxYP5QkZbYz8D88AODzB08WnLMJBK3pVm2AbUwHDiTkzizgc1YgoHnGT4tbEAthw3YGHjMfxxsq0jccIDBDOiXw/gdljjnP0iLAQNEC/s3AloSgA5rOADTkgPUwoPfFskzb4wtEo4lG7AxsxUwnDmTZjyzmadYIgGPX/iOpz+8+aPGzkC+vXkDQ0VFsmw/e/vGDx97cIeYwgEYixlCOTaAGIk9B7AqBwH5BjQBewj1A7eWUTAKRsEoGHEAABJeUYA70dWuAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-5753-6568","institution":"University of Tokyo: Tokyo Daigaku","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Yoshiya","middleName":"","lastName":"Usui","suffix":""},{"id":47110461,"identity":"d3b8689b-ce82-4592-9212-822ea6216ed5","order_by":1,"name":"Makoto Uyeshima","email":"","orcid":"","institution":"The University of Tokyo: Tokyo Daigaku","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Makoto","middleName":"","lastName":"Uyeshima","suffix":""}],"badges":[],"createdAt":"2021-08-10 10:41:57","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-798901/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-798901/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":12696906,"identity":"be076fad-8199-4079-b0f6-d4854a5469fa","added_by":"auto","created_at":"2021-08-23 22:25:16","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":957474,"visible":true,"origin":"","legend":"Schematic view illustrating how to calculate the voltage difference along each dipole of the NMT observation station. Here, E1 and E2 are the electric field components along the edges of the triangle, L1 and L2 are the lengths of the edges, i is the imaginary unit, μ0 is the magnetic permeability of vacuum, Hn is the magnetic field component normal to the triangle, and S is the area of the triangle. The solid lines indicate the element edges, while a thick dash line denotes a dipole of the NMT observation station. The black-filled circle denotes the endpoints of the dipole. The voltage difference along each dipole is computed by summing the voltage differences dV of the small segments.","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/b4ee1a4791fd771d4f15ec58.png"},{"id":12696911,"identity":"51c70fcf-505d-4819-af26-9538908912c4","added_by":"auto","created_at":"2021-08-23 22:25:16","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":4881871,"visible":true,"origin":"","legend":"Electrical resistivity structures obtained by Comb-A. (a) True resistivity structure (OC model). (b)-(c) Resultant resistivity structures obtained by the combined inversion with three different initial models. The lowermost panels are the vertical cross-sections of the profile along the major axis of the oblique conductor, which is shown as a white line in the upper-left panel. The inverted triangles indicate the locations of observation stations. We used the bottom-right point (the station at x= -18 km and y=18 km) as the reference station for calculating HMTF.","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/84c4e5a98986c40e6f1accf8.png"},{"id":12696910,"identity":"2c1d7fba-c98e-4c69-a6fa-18c0e452f503","added_by":"auto","created_at":"2021-08-23 22:25:16","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":6195454,"visible":true,"origin":"","legend":"Electrical resistivity structures obtained by Comb-B. (a) True resistivity structure (OC model). (b)-(c) Resultant resistivity structures obtained by the combined inversion with three different initial models. The lowermost panels indicate the vertical cross-sections of the profile along the major axis of the oblique conductor, which is shown as a white line in the upper-left panel. The inverted triangles indicate the locations of observation stations of PT, VMTF, and HMTF. The broken lines with circular ends indicate the dipoles of the NMT stations. We used the bottom-right point (the station at x= -18 km and y=18 km) as the reference station for calculating HMTF and NMTRF.","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/bc764f324c3662c864584151.png"},{"id":12697039,"identity":"00f92cc2-3b55-4840-9f3d-da6bbe7b0ece","added_by":"auto","created_at":"2021-08-23 22:28:16","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":873099,"visible":true,"origin":"","legend":"Electrical resistivity variation with a depth at (a) (x, y) = (10 km, -10 km) and (b) (x, y) = (-10 km, 10 km). The thick black lines indicate the resistivity variation of the true resistivity structure. The broken colored and solid-colored lines indicate the resistivity variations of the resistivity structure obtained by Comb-A and Comb-B, respectively.","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/cae84f338154401b2b16103e.png"},{"id":12696905,"identity":"af274437-706e-44c5-9f2d-9500d30d5f3f","added_by":"auto","created_at":"2021-08-23 22:25:16","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":477526,"visible":true,"origin":"","legend":"Objective function versus the iteration number for combined inversions with different initial models. The broken and solid lines indicate the objective function changes during Comb-A and Comb-B inversions.","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/d74d4a1ec256fb1225d48b8e.png"},{"id":13670484,"identity":"44288fbe-f0fb-40c6-9ff6-7c5ac22b60dd","added_by":"auto","created_at":"2021-09-17 11:05:28","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1065875,"visible":true,"origin":"","legend":"","description":"","filename":"NMTWMT3D.pdf","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1_covered.pdf"},{"id":12697356,"identity":"90378b3e-6963-4366-b465-84e29cfc0fac","added_by":"auto","created_at":"2021-08-23 22:31:31","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":679706,"visible":true,"origin":"","legend":"","description":"","filename":"NMTWMT3D.pdf","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1_covered.pdf"},{"id":12697355,"identity":"0f53caf2-fc1d-4cb3-8aa4-88a9afeb8c3b","added_by":"auto","created_at":"2021-08-23 22:31:16","extension":"jpg","order_by":9,"title":"","display":"","copyAsset":false,"role":"supplement","size":517478,"visible":true,"origin":"","legend":"","description":"","filename":"GraphicalAbstract.jpg","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/0c0185b5b1457eb7f8248ef3.jpg"},{"id":12696907,"identity":"058b3d21-f829-4a8c-8d3a-fce834819686","added_by":"auto","created_at":"2021-08-23 22:25:16","extension":"docx","order_by":10,"title":"","display":"","copyAsset":false,"role":"supplement","size":591863,"visible":true,"origin":"","legend":"","description":"","filename":"supportinginformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-798901/v1/0df4c75526d55197779d4713.docx"}],"financialInterests":"","formattedTitle":"\u003cp\u003eNew 3-D Combined Inversion Scheme Using Response Functions Free From Galvanic Distortion\u003c/p\u003e","fulltext":[{"header":"Full Text","content":"This preprint is available for \u003ca href='/article/rs-798901/latest.pdf' target='_blank'\u003edownload as a PDF\u003c/a\u003e."}],"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":false,"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":"magnetotelluric inversion, Network-MT method, galvanic distortion, finite element method, phase tensor, magnetic transfer function, tetrahedral mesh","lastPublishedDoi":"10.21203/rs.3.rs-798901/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-798901/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe combined inversion using distortion-free response functions is an effective approach to robustly estimate the 3-D electrical resistivity structure against the distortions caused by near-surface resistivity anomalies. However, previous combined inversion analyses have presented a significant dependency of the inversion results on initial and prior models. Therefore, in this study, we evaluated the effectiveness of the following two new types of 3-D combined inversion using distortion-free response functions: one uses the phase tensor and the vertical and inter-station horizontal magnetic transfer functions, while the other uses the Network-MT response functions, in addition to the former. Because long dipoles are used, the Network-MT response function is negligibly affected by galvanic distortion. To access the combined inversion approach, we developed a novel 3-D inversion scheme combining the response functions of the usual magnetotelluric measurements and the Network-MT response function. The synthetic inversion analysis demonstrated that both of the proposed combined inversions can recover the characteristic resistivity distributions of the target model without a significant dependence on the initial models, at least in the shallow part. These results demonstrate that the combined inversions using only distortion-free response functions have the potential to estimate subsurface resistivity more robustly than what was previously thought. Furthermore, we confirmed that the combined inversion using the Network-MT response function can make the resultant resistivity structure closer to the actual one and enhance the stability of the inversion. This result suggests that the combined use of the Network-MT response function is the preferred approach.\u003c/p\u003e","manuscriptTitle":"New 3-D Combined Inversion Scheme Using Response Functions Free From Galvanic Distortion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-08-23 22:25:14","doi":"10.21203/rs.3.rs-798901/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":"6763865e-ca3b-4bb6-8fea-3e7ff99c57b4","owner":[],"postedDate":"August 23rd, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":6639788,"name":"Geology"},{"id":6639789,"name":"Planetary Science"}],"tags":[],"updatedAt":"2021-11-24T12:42:57+00:00","versionOfRecord":[],"versionCreatedAt":"2021-08-23 22:25:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-798901","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-798901","identity":"rs-798901","version":["v1"]},"buildId":"rHA-KDH7Qsr4HCuvH75dn","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}