Control of pore geometry on the strength, elastic anisotropy and acoustic emission output of vesicular lavas from Nevados de Chillán, Chile

Control of pore geometry on the strength, elastic anisotropy and acoustic emission output of vesicular lavas from Nevados de Chillán, Chile | 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 Control of pore geometry on the strength, elastic anisotropy and acoustic emission output of vesicular lavas from Nevados de Chillán, Chile Fernanda Merchán, John Browning, Gloria Arancibia, David Healy, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8114197/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Apr, 2026 Read the published version in Bulletin of Volcanology → Version 1 posted 9 You are reading this latest preprint version Abstract The strength and stiffness of lavas, as well as their propensity to fracture and develop permeable flow networks, are all governed by microstructural heterogeneity. In vesicular andesitic–dacitic lavas from the Nevados de Chillán Volcanic Complex (NChVC) in Chile, we show that uniaxial compressive strength (UCS) and Young’s modulus (E) depend not only on connected porosity but also on the distribution, orientation, size and aspect ratio of pores. Pore fabrics were first quantified via 2D analyses (transparent sections and surface imaging) and 3D micro–computed tomography (micro-CT). Then, using cylinders with pores aligned parallel, perpendicular, and inclined to the loading direction, we performed UCS tests instrumented with acoustic emission (AE) monitoring. Loading perpendicular to the pore major axis presents the lowest strength and stiffness and triggers AE output at low stress, whereas loading parallel to the pore major axis initiates damage at higher stress, attains relatively higher strength, and culminates in macroscopic failure with higher rates of AE concentrated near the peak stress. Mixed AE patterns are observed when loading at an inclined angle to the pore major axis. These observations are consistent with the theory of microcrack nucleation and propagation controlled by stress concentration around elliptical pores. While porosity exerts a first-order control on the overall magnitude of strength and stiffness, we conclude that pore alignment, aspect ratio and directional variability fundamentally modulate failure style, damage evolution and rock mechanical properties. Operationally, this framework anticipates preferential directions of weakness and damage evolution prior to failure, thereby supporting assessments of the mechanical stability of lava domes, levees, and scoria cones composed of high porosity materials. Microstructural heterogeneity Pore Geometry Uniaxial Compressive Strength Nevados de Chillán Lava flow Full Text Additional Declarations No competing interests reported. Supplementary Files MerchanBullvolcsupplementaryinformation.docx Cite Share Download PDF Status: Published Journal Publication published 10 Apr, 2026 Read the published version in Bulletin of Volcanology → Version 1 posted Editorial decision: Revision requested 02 Jan, 2026 Reviews received at journal 23 Dec, 2025 Reviews received at journal 16 Dec, 2025 Reviewers agreed at journal 09 Dec, 2025 Reviewers agreed at journal 28 Nov, 2025 Reviewers invited by journal 28 Nov, 2025 Editor assigned by journal 20 Nov, 2025 Submission checks completed at journal 20 Nov, 2025 First submitted to journal 14 Nov, 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. 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-8114197","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":547716393,"identity":"d99472db-91e2-4551-8aae-50609d5ef7a7","order_by":0,"name":"Fernanda Merchán","email":"","orcid":"","institution":"Pontificia Universidad Católica de Chile","correspondingAuthor":false,"prefix":"","firstName":"Fernanda","middleName":"","lastName":"Merchán","suffix":""},{"id":547716394,"identity":"443ca990-f56e-4bf0-9b1c-2a9111abd79f","order_by":1,"name":"John 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Chile","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bulletin-of-volcanology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"buvo","sideBox":"Learn more about [Bulletin of Volcanology](http://link.springer.com/journal/445)","snPcode":"445","submissionUrl":"https://www.editorialmanager.com/buvo/default2.aspx","title":"Bulletin of Volcanology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Microstructural heterogeneity, Pore Geometry, Uniaxial Compressive Strength, Nevados de Chillán, Lava flow","lastPublishedDoi":"10.21203/rs.3.rs-8114197/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8114197/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe strength and stiffness of lavas, as well as their propensity to fracture and develop permeable flow networks, are all governed by microstructural heterogeneity. In vesicular andesitic\u0026ndash;dacitic lavas from the Nevados de Chill\u0026aacute;n Volcanic Complex (NChVC) in Chile, we show that uniaxial compressive strength (UCS) and Young\u0026rsquo;s modulus (E) depend not only on connected porosity but also on the distribution, orientation, size and aspect ratio of pores. Pore fabrics were first quantified via 2D analyses (transparent sections and surface imaging) and 3D micro\u0026ndash;computed tomography (micro-CT). Then, using cylinders with pores aligned parallel, perpendicular, and inclined to the loading direction, we performed UCS tests instrumented with acoustic emission (AE) monitoring. Loading perpendicular to the pore major axis presents the lowest strength and stiffness and triggers AE output at low stress, whereas loading parallel to the pore major axis initiates damage at higher stress, attains relatively higher strength, and culminates in macroscopic failure with higher rates of AE concentrated near the peak stress. Mixed AE patterns are observed when loading at an inclined angle to the pore major axis. These observations are consistent with the theory of microcrack nucleation and propagation controlled by stress concentration around elliptical pores. While porosity exerts a first-order control on the overall magnitude of strength and stiffness, we conclude that pore alignment, aspect ratio and directional variability fundamentally modulate failure style, damage evolution and rock mechanical properties. Operationally, this framework anticipates preferential directions of weakness and damage evolution prior to failure, thereby supporting assessments of the mechanical stability of lava domes, levees, and scoria cones composed of high porosity materials.\u003c/p\u003e","manuscriptTitle":"Control of pore geometry on the strength, elastic anisotropy and acoustic emission output of vesicular lavas from Nevados de Chillán, Chile","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-20 09:12:29","doi":"10.21203/rs.3.rs-8114197/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-02T10:36:45+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-23T11:10:07+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-16T17:08:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"152884778717922527584492485977630799207","date":"2025-12-09T09:56:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"207115986729885187070315538782084812168","date":"2025-11-28T11:34:21+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-28T10:46:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-20T09:22:40+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-20T09:20:03+00:00","index":"","fulltext":""},{"type":"submitted","content":"Bulletin of Volcanology","date":"2025-11-14T12:43:36+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bulletin-of-volcanology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"buvo","sideBox":"Learn more about [Bulletin of Volcanology](http://link.springer.com/journal/445)","snPcode":"445","submissionUrl":"https://www.editorialmanager.com/buvo/default2.aspx","title":"Bulletin of Volcanology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7ebddee7-63bc-4a8b-8fbf-339e8f98fa72","owner":[],"postedDate":"November 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-13T16:01:22+00:00","versionOfRecord":{"articleIdentity":"rs-8114197","link":"https://doi.org/10.1007/s00445-026-01968-8","journal":{"identity":"bulletin-of-volcanology","isVorOnly":false,"title":"Bulletin of Volcanology"},"publishedOn":"2026-04-10 15:58:26","publishedOnDateReadable":"April 10th, 2026"},"versionCreatedAt":"2025-11-20 09:12:29","video":"","vorDoi":"10.1007/s00445-026-01968-8","vorDoiUrl":"https://doi.org/10.1007/s00445-026-01968-8","workflowStages":[]},"version":"v1","identity":"rs-8114197","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8114197","identity":"rs-8114197","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}