{"@context":{"@vocab":"https://cir.nii.ac.jp/schema/1.0/","rdfs":"http://www.w3.org/2000/01/rdf-schema#","dc":"http://purl.org/dc/elements/1.1/","dcterms":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","prism":"http://prismstandard.org/namespaces/basic/2.0/","cinii":"http://ci.nii.ac.jp/ns/1.0/","datacite":"https://schema.datacite.org/meta/kernel-4/","ndl":"http://ndl.go.jp/dcndl/terms/","jpcoar":"https://github.com/JPCOAR/schema/blob/master/2.0/"},"@id":"https://cir.nii.ac.jp/crid/1361699995223049856.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.1029/2008jb005664"}},{"identifier":{"@type":"URI","@value":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2008JB005664"}},{"identifier":{"@type":"URI","@value":"https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008JB005664"}}],"dc:title":[{"@value":"Experimental observations of water‐like behavior of initially fluidized, dam break granular flows and their relevance for the propagation of ash‐rich pyroclastic flows"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>The physics of ash‐rich pyroclastic flows were investigated through laboratory dam break experiments using both granular material and water. Flows of glass beads of 60–90 <jats:italic>μ</jats:italic>m in diameter generated from the release of initially fluidized, slightly expanded (2.5–4.5%) columns behave as their inertial water counterparts for most of their emplacement. For a range of initial column height to length ratios of 0.5–3, both types of flows propagate in three stages, controlled by the time scale of column free fall ∼(<jats:italic>h</jats:italic><jats:sub>0</jats:sub>/<jats:italic>g</jats:italic>)<jats:sup>1/2</jats:sup>, where <jats:italic>h</jats:italic><jats:sub>0</jats:sub> denotes column height and <jats:italic>g</jats:italic> denotes gravitational acceleration. Flows first accelerate as the column collapses. Transition to a second, constant velocity phase occurs at a time <jats:italic>t</jats:italic>/(<jats:italic>h</jats:italic><jats:sub>0</jats:sub>/<jats:italic>g</jats:italic>)<jats:sup>1/2</jats:sup> ∼ 1.5. The flow velocity is then <jats:italic>U</jats:italic> ∼ <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/jgrb15706-math-0001.gif\" xlink:title=\"equation image\"/>(<jats:italic>gh</jats:italic><jats:sub>0</jats:sub>)<jats:sup>1/2</jats:sup>, larger than that for dry (initially nonfluidized) granular flows. Transition to a last, third phase occurs at <jats:italic>t</jats:italic>/(<jats:italic>h</jats:italic><jats:sub>0</jats:sub>/<jats:italic>g</jats:italic>)<jats:sup>1/2</jats:sup> ∼ 4. Granular flow behavior then departs from that of water flows as the former steadily decelerates and the front position varies as <jats:italic>t</jats:italic><jats:sup>1/3</jats:sup>, as in dry flows. Motion ceases at <jats:italic>t</jats:italic>/(<jats:italic>h</jats:italic><jats:sub>0</jats:sub>/<jats:italic>g</jats:italic>)<jats:sup>1/2</jats:sup> ∼ 6.5 with normalized runout <jats:italic>x</jats:italic>/<jats:italic>h</jats:italic><jats:sub>0</jats:sub> ∼ 5.5–6. The equivalent behavior of water and highly concentrated granular flows up to the end of the second phase indicates a similar overall bulk resistance, although mechanisms of energy dissipation in both cases would be different. Interstitial air‐particle viscous interactions can be dominant and generate pore fluid pressure sufficient to confer a fluid‐inertial behavior to the dense granular flows before they enter a granular‐frictional regime at late stages. Efficient gas‐particle interactions in dense, ash‐rich pyroclastic flows may promote a water‐like behavior during most of their propagation.</jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1380285532879748231","@type":"Researcher","foaf:name":[{"@value":"O. Roche"}],"jpcoar:affiliationName":[{"@value":"Laboratoire Magmas et Volcans OPGC, Université Blaise Pascal, IRD, CNRS  Clermont‐Ferrand France"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699995223049856","@type":"Researcher","foaf:name":[{"@value":"S. Montserrat"}],"jpcoar:affiliationName":[{"@value":"Department of Civil Engineering Universidad de Chile  Santiago Chile"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699995223049858","@type":"Researcher","foaf:name":[{"@value":"Y. Niño"}],"jpcoar:affiliationName":[{"@value":"Department of Civil Engineering Universidad de Chile  Santiago Chile"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699995223049859","@type":"Researcher","foaf:name":[{"@value":"A. Tamburrino"}],"jpcoar:affiliationName":[{"@value":"Department of Civil Engineering Universidad de Chile  Santiago Chile"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"01480227"}],"prism:publicationName":[{"@value":"Journal of Geophysical Research: Solid Earth"}],"dc:publisher":[{"@value":"American Geophysical Union (AGU)"}],"prism:publicationDate":"2008-12","prism:volume":"113","prism:number":"B12","prism:startingPage":"B12203"},"reviewed":"false","dc:rights":["http://onlinelibrary.wiley.com/termsAndConditions#vor"],"url":[{"@id":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2008JB005664"},{"@id":"https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008JB005664"}],"createdAt":"2008-12-09","modifiedAt":"2023-10-12","relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1360857593667431040","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Validation of a two-layer depth-averaged model by comparison with an experimental dilute stratified pyroclastic density current"}]},{"@id":"https://cir.nii.ac.jp/crid/1390292958815219968","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Applicability of numerical two-layer depth-averaged models for pyroclastic density currents to powder snow avalanches: Toward developing a unified model for powder snow avalanches and pyroclastic density currents"},{"@language":"ja","@value":"煙型雪崩に対する二層火砕流数値モデルの応用可能性：雪崩・火砕流の統一モデル構築に向けて"}]},{"@id":"https://cir.nii.ac.jp/crid/1390574411905749888","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Numerical Simulations of Dome-Collapse Pyroclastic Density Currents Using faSavageHutterFOAM: Application to the 3 June 1991 Eruption of Unzen Volcano, Japan"}]},{"@id":"https://cir.nii.ac.jp/crid/2051151841916390400","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"A numerical shallow-water model for gravity currents for a wide range of density differences"}]}],"dataSourceIdentifier":[{"@type":"CROSSREF","@value":"10.1029/2008jb005664"},{"@type":"CROSSREF","@value":"10.20965/jdr.2022.p0768_references_DOI_ZRF3hAmK7qWFCW8aHPWnsCV5XK1"},{"@type":"CROSSREF","@value":"10.1186/s40645-017-0120-2_references_DOI_ZRF3hAmK7qWFCW8aHPWnsCV5XK1"},{"@type":"CROSSREF","@value":"10.1007/s00445-021-01493-w_references_DOI_ZRF3hAmK7qWFCW8aHPWnsCV5XK1"},{"@type":"CROSSREF","@value":"10.5331/seppyo.84.4_323_references_DOI_ZRF3hAmK7qWFCW8aHPWnsCV5XK1"}]}