Seismic Noise as a Window into Volcanic Unrest: Observations from Ruapehu, New Zealand in 2022.

Seismic Noise as a Window into Volcanic Unrest: Observations from Ruapehu, New Zealand in 2022. | 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 Seismic Noise as a Window into Volcanic Unrest: Observations from Ruapehu, New Zealand in 2022. Mustafa Almassri, Oliver D. Lamb, Stuart Mead, Georg F. Zellmer This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6883561/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 Ruapehu is an active andesitic composite volcano that erupted twice (in 2006 and 2007), following its major eruptive sequence in 1995–1996. Those eruptions were phreatic explosions that occurred with few no precursors. In March 2022, Ruapehu entered a period of significant volcanic unrest characterized by volcanic tremor, gas emissions, and heating of the crater lake. To monitor temporal variations in the elastic properties of Ruapehu volcano during this unrest episode, we applied the method ''Moving Window Cross-Spectral Analysis". This technique revealed a $\sim$0.5$%$ decrease in relative seismic velocity at the beginning of 2022, coinciding with a small earthquake swarm. This correlation suggests that the process triggering the swarm may also be responsible for the observed velocity drop. A similar $\sim$0.5$%$ relative seismic velocity reduction was observed during the volcanic unrest in the North-East sector of the volcanic edifice. This seismic velocity drop appears to be a reversible process, likely driven by magmatic or fluid movement. Possible causes include the opening of fractures within the magmatic reservoir, fluid fluxes (water, gas, or magma), magmatic anomalies (magma that does not reach the surface but intrudes into the subsurface), or environmental factors (e.g. rainfall or atmospheric pressure changes) that may contribute to the formation of low-velocity zones. By mid-May 2022, volcanic tremor and crater lake temperature began to decline, most likely due to a reduction in fluid circulation, through sealing processes. However, the reduction in seismic velocity persisted, indicating potential ongoing subsurface alteration. This study highlights the importance of using ambient noise monitoring to detect seismic velocity changes during volcanic unrest. By providing potential insights into subsurface processes, this method can complement current monitoring techniques and improve eruption forecasting and hazard assessment at Ruapehu. ambient seismic noise Ruapehu volcano monitoring seismic velocity variations Full Text Supplementary Files volcanicunrestruapehusupplementary.pdf 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-6883561","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":528988013,"identity":"b1da8c32-1c25-46d0-b260-6a93962f0e1d","order_by":0,"name":"Mustafa Almassri","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFElEQVRIiWNgGAWjYNACGwglAWQx84NYCQV41TM2MKTBtaSxSzaAtBgQr+Uwv8EBEBOPFt0Z6c8f/Eiwy+efdvjhjZ870qSNz69O/PDAgEGeX+wAVi1mN3IMG3sSki1n3E4ztuw9Y2NsduPtZgmgwwxnzk7ApYWxgfcHswHD7QQzCd62tGSzG2c3gLQkGNzGpSX9YeOfhHoD+dvp3yT/th2u3zzj7OYf+LUkGDbzJBw2MLidYybN23aY2YC/dxt+W868MZwtk3DcwPB2TrG1bFsas8QN3m0WCQYSuP1yPP3BxzcJ1QZyt9M33nzbBozK/rObb/6osJHnl8auBQuQAKuUIFY5CPAfIEX1KBgFo2AUjAAAADkXZT6bwDBdAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0009-0007-6895-853X","institution":"Massey University - Manawatu Campus: Massey University","correspondingAuthor":true,"prefix":"","firstName":"Mustafa","middleName":"","lastName":"Almassri","suffix":""},{"id":528988014,"identity":"a8e6f8a8-c3f8-4d5e-8267-ce6e479d6ceb","order_by":1,"name":"Oliver D. Lamb","email":"","orcid":"","institution":"Te Pu Ao: GNS Science Ltd","correspondingAuthor":false,"prefix":"","firstName":"Oliver","middleName":"D.","lastName":"Lamb","suffix":""},{"id":528988015,"identity":"63c55031-6688-454f-9014-26e2116cf03a","order_by":2,"name":"Stuart Mead","email":"","orcid":"","institution":"Massey University - Manawatu Campus: Massey University","correspondingAuthor":false,"prefix":"","firstName":"Stuart","middleName":"","lastName":"Mead","suffix":""},{"id":528988016,"identity":"e1bc18df-bd67-4a92-86a2-668c2f1fac6c","order_by":3,"name":"Georg F. Zellmer","email":"","orcid":"","institution":"University of Bonn Faculty of Mathematics and Natural Sciences: Rheinische Friedrich-Wilhelms-Universitat Mathematisch-Naturwissenschaftliche Fakultat","correspondingAuthor":false,"prefix":"","firstName":"Georg","middleName":"F.","lastName":"Zellmer","suffix":""}],"badges":[],"createdAt":"2025-06-13 00:43:53","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6883561/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6883561/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":94449493,"identity":"5bc37c78-eca4-4627-bb82-26f4c5dda92d","added_by":"auto","created_at":"2025-10-27 14:38:29","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":9475,"visible":true,"origin":"","legend":"","description":"","filename":"buvoBUVOD2500111.xml","url":"https://assets-eu.researchsquare.com/files/rs-6883561/v1/7b84e353f2a38cb3687e82b7.xml"},{"id":94449709,"identity":"6cdfeb49-969f-47b9-bf8b-62e568d919dd","added_by":"auto","created_at":"2025-10-27 14:38:41","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1031,"visible":true,"origin":"","legend":"","description":"","filename":"BUVOD25001114200.go.xml","url":"https://assets-eu.researchsquare.com/files/rs-6883561/v1/b4add0e8d4cf4d5399d6ac82.xml"},{"id":94450255,"identity":"4dd3b8ca-215b-4b4f-aa3b-9f36de647fc5","added_by":"auto","created_at":"2025-10-27 14:39:09","extension":"xml","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":871,"visible":true,"origin":"","legend":"","description":"","filename":"BUVOD2500111Import.xml","url":"https://assets-eu.researchsquare.com/files/rs-6883561/v1/3e17f55c62c23626fdc16d62.xml"},{"id":96365909,"identity":"1011e140-2f2a-4c23-9518-cb1a77878e39","added_by":"auto","created_at":"2025-11-20 10:10:56","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4056631,"visible":true,"origin":"","legend":"","description":"","filename":"ArticleBullVolc.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6883561/v1_covered_f8abc549-d5dd-4a23-aed2-902e252ffcf0.pdf"},{"id":94449927,"identity":"b6aef4d2-d683-44b3-96d4-36cee62903fa","added_by":"auto","created_at":"2025-10-27 14:38:51","extension":"pdf","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":11126965,"visible":true,"origin":"","legend":"","description":"","filename":"volcanicunrestruapehusupplementary.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6883561/v1/52f6e87188e135a09d238918.pdf"}],"financialInterests":"","formattedTitle":"Seismic Noise as a Window into Volcanic Unrest: Observations from Ruapehu, New Zealand in 2022.","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":"ambient seismic noise, Ruapehu, volcano monitoring, seismic velocity variations","lastPublishedDoi":"10.21203/rs.3.rs-6883561/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6883561/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Ruapehu is an active andesitic composite volcano that erupted twice (in 2006 and 2007), following its major eruptive sequence in 1995–1996. Those eruptions were phreatic explosions that occurred with few no precursors. In March 2022, Ruapehu entered a period of significant volcanic unrest characterized by volcanic tremor, gas emissions, and heating of the crater lake. To monitor temporal variations in the elastic properties of Ruapehu volcano during this unrest episode, we applied the method ''Moving Window Cross-Spectral Analysis\". This technique revealed a $\\sim$0.5$\\%$ decrease in relative seismic velocity at the beginning of 2022, coinciding with a small earthquake swarm. This correlation suggests that the process triggering the swarm may also be responsible for the observed velocity drop. A similar $\\sim$0.5$\\%$ relative seismic velocity reduction was observed during the volcanic unrest in the North-East sector of the volcanic edifice. This seismic velocity drop appears to be a reversible process, likely driven by magmatic or fluid movement. Possible causes include the opening of fractures within the magmatic reservoir, fluid fluxes (water, gas, or magma), magmatic anomalies (magma that does not reach the surface but intrudes into the subsurface), or environmental factors (e.g. rainfall or atmospheric pressure changes) that may contribute to the formation of low-velocity zones. By mid-May 2022, volcanic tremor and crater lake temperature began to decline, most likely due to a reduction in fluid circulation, through sealing processes. However, the reduction in seismic velocity persisted, indicating potential ongoing subsurface alteration. This study highlights the importance of using ambient noise monitoring to detect seismic velocity changes during volcanic unrest. By providing potential insights into subsurface processes, this method can complement current monitoring techniques and improve eruption forecasting and hazard assessment at Ruapehu.","manuscriptTitle":"Seismic Noise as a Window into Volcanic Unrest: Observations from Ruapehu, New Zealand in 2022.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-27 11:29:06","doi":"10.21203/rs.3.rs-6883561/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":"0a1ba661-4974-4362-ace1-03e7bec25421","owner":[],"postedDate":"October 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-08T22:23:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-27 11:29:06","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6883561","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6883561","identity":"rs-6883561","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}