pubs.json
1 [ 2 {"id":"2016AGUFM.V11C2790J","author":[{"family":"Johnson","given":"P. J."},{"family":"Valentine","given":"G."},{"family":"Lowry","given":"C."},{"family":"Sonder","given":"I."},{"family":"Stauffer","given":"P. H."},{"family":"Santacoloma","given":"C."},{"family":"Pulgarín","given":"B."},{"family":"Adriana","given":"A."}],"citation-key":"2016AGUFM.V11C2790J","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2016,12]]},"number":"V11C-2790","page":"V11C-2790","title":"Long boundary drainage as a source of lahars: Can big cracks make big floods?","type":"paper-conference","volume":"2016"}, 3 {"id":"2016AGUFM.V53C3094M","author":[{"family":"Moitra","given":"P."},{"family":"Sonder","given":"I."},{"family":"Valentine","given":"G."}],"citation-key":"2016AGUFM.V53C3094M","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2016,12]]},"number":"V53C-3094","page":"V53C-3094","title":"Estimates of heat flux during magma-water interaction: An experimental approach","type":"paper-conference","volume":"2016"}, 4 {"id":"2018AGUFM.V23F0126V","author":[{"family":"Valentine","given":"G."},{"family":"Sonder","given":"I."},{"family":"Harp","given":"A."}],"citation-key":"2018AGUFM.V23F0126V","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2018,12]]},"number":"V23F-0126","page":"V23F-0126","title":"Field-scale volcanology experiments workshop - outcomes, science and recommendations","type":"paper-conference","volume":"2018"}, 5 {"id":"2018AGUFM.V23F0127G","author":[{"family":"Graettinger","given":"A. H."},{"family":"Oppenheimer","given":"J."},{"family":"Soldati","given":"A."},{"family":"Befus","given":"K. S."},{"family":"Sonder","given":"I."}],"citation-key":"2018AGUFM.V23F0127G","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2018,12]]},"number":"V23F-0127","page":"V23F-0127","title":"Insights into volcanic crater morphology and proximal deposits from multi-blast large scale experiments at University at Buffalo NSF Collaborative Blast Workshop","type":"paper-conference","volume":"2018"}, 6 {"id":"2018AGUFM.V23F0128M","author":[{"family":"Matoza","given":"R. S."},{"family":"Neilsen","given":"T. B."},{"family":"Waite","given":"G. P."},{"family":"Medici","given":"E. F."},{"family":"Valentine","given":"G."},{"family":"Sonder","given":"I."},{"family":"Harp","given":"A."},{"family":"Maher","given":"S."},{"family":"Sanderson","given":"R. W."},{"family":"Butts","given":"C."},{"family":"Escobedo","given":"J. A."},{"family":"Hawkes","given":"M. R."},{"family":"Lopez","given":"C. A."},{"family":"Lysenko","given":"E."},{"family":"McKay","given":"M. G."},{"family":"Shaw","given":"S. A."}],"citation-key":"2018AGUFM.V23F0128M","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2018,12]]},"number":"V23F-0128","page":"V23F-0128","title":"Seismo-acoustic measurements of an outdoor, field-scale, explosive “volcano”","type":"paper-conference","volume":"2018"}, 7 {"id":"2018AGUFM.V23J0172S","author":[{"family":"Sonder","given":"I."},{"family":"Harp","given":"A."},{"family":"Graettinger","given":"A."},{"family":"Moitra","given":"P."},{"family":"Valentine","given":"G."},{"family":"Büttner","given":"R."},{"family":"Zimanowski","given":"B."}],"citation-key":"2018AGUFM.V23J0172S","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2018,12]]},"number":"V23J-0172","page":"V23J-0172","title":"Meter-scale experiments on magma-water interaction","type":"paper-conference","volume":"2018"}, 8 {"id":"2018AGUFM.V23J0173M","author":[{"family":"Moitra","given":"P."},{"family":"Sonder","given":"I."},{"family":"Valentine","given":"G."}],"citation-key":"2018AGUFM.V23J0173M","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2018,12]]},"number":"V23J-0173","page":"V23J-0173","title":"Magma-to-water heat transfer rates with implications for quench-induced fragmentation","type":"paper-conference","volume":"2018"}, 9 {"id":"2018AGUFM.V23J0177B","author":[{"family":"Bennis","given":"K."},{"family":"Graettinger","given":"A."},{"family":"Sonder","given":"I."}],"citation-key":"2018AGUFM.V23J0177B","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2018,12]]},"number":"V23J-0177","page":"V23J-0177","title":"Field observations on sediment-magma mingling textures at 71 Gulch inform analog experiments using remolten basalt","type":"paper-conference","volume":"2018"}, 10 {"id":"2019AGUFM.V43G0178V","author":[{"family":"Valentine","given":"G."},{"family":"Sonder","given":"I."}],"citation-key":"2019AGUFM.V43G0178V","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2019,12]]},"number":"V43G-0178","page":"V43G-0178","title":"Phreatomagmatic explosion triggers - special pleading?","type":"paper-conference","volume":"2019"}, 11 {"id":"2019AGUFM.V43H0188M","author":[{"family":"Moitra","given":"P."},{"family":"Sonder","given":"I."},{"family":"Valentine","given":"G."}],"citation-key":"2019AGUFM.V43H0188M","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2019,12]]},"number":"V43H-0188","page":"V43H-0188","title":"Quench-induced fragmentation of magma during subaqueous eruptions","type":"paper-conference","volume":"2019"}, 12 {"id":"2019AGUFM.V51C..04S","author":[{"family":"Sonder","given":"I."},{"family":"Harp","given":"A."},{"family":"Graettinger","given":"A. H."},{"family":"Moitra","given":"P."},{"family":"Valentine","given":"G."},{"family":"Büttner","given":"R."},{"family":"Zimanowski","given":"B."}],"citation-key":"2019AGUFM.V51C..04S","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2019,12]]},"number":"V51C-04","page":"V51C-04","title":"Geometry and time dependencies of intense magma-water interaction experiments on decimeter and meter scale","type":"paper-conference","volume":"2019"}, 13 {"id":"2019ASAJ..145.1869N","author":[{"family":"Neilsen","given":"Tracianne B."},{"family":"Matoza","given":"Robin S."},{"family":"Maher","given":"Sean"},{"family":"McKay","given":"Margaret G."},{"family":"Sanderson","given":"Richard"},{"family":"Valentine","given":"Greg A."},{"family":"Sonder","given":"Ingo"},{"family":"Harp","given":"Andrew G."}],"citation-key":"2019ASAJ..145.1869N","container-title":"Acoustical Society of America Journal","DOI":"10.1121/1.5101754","issue":"3","issued":{"date-parts":[[2019,3]]},"page":"1869-1869","title":"Preliminary analyses of seismo-acoustic wave propagation in outdoor field-scale analog volcanic explosions","type":"article-journal","volume":"145"}, 14 {"id":"2020AGUFMV044...05M","author":[{"family":"Moitra","given":"P."},{"family":"Sonder","given":"I."}],"citation-key":"2020AGUFMV044...05M","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2020,12]]},"number":"V044-05","page":"V044-05","title":"Effect of relative lava-water motion on the spreading and fragmentation of submarine lavas","type":"paper-conference","volume":"2020"}, 15 {"id":"2022AGUFM.V12B0047M","author":[{"family":"Moitra","given":"Pranabendu"},{"family":"Sonder","given":"Ingo"}],"citation-key":"2022AGUFM.V12B0047M","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2022,12]]},"number":"V12B-0047","page":"V12B-0047","title":"Effects of vapor bubbles and velocity on the cooling rates of lava and pyroclasts during submarine eruptions","type":"paper-conference","volume":"2022"}, 16 {"id":"2022AGUFM.V16A..06S","author":[{"family":"Sonder","given":"Ingo"},{"family":"Moitra","given":"Pranabendu"}],"citation-key":"2022AGUFM.V16A..06S","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2022,12]]},"number":"V16A-06","page":"V16A-06","title":"Measurements of stability and lifetime of film boiling states at the magma-water interface","type":"paper-conference","volume":"2022"}, 17 {"id":"2022AGUFM.V42B..05S","author":[{"family":"Sonder","given":"Ingo"},{"family":"Graettinger","given":"Alison"},{"family":"Neilsen","given":"Tracianne B."},{"family":"Matoza","given":"Robin S."},{"family":"Taddeucci","given":"Jacopo"},{"family":"Lev","given":"Einat"},{"family":"Tsunematsu","given":"Kae"},{"family":"Waite","given":"Gregory P."},{"family":"Valentine","given":"Greg"},{"family":"Befus","given":"Kenneth S."}],"citation-key":"2022AGUFM.V42B..05S","container-title":"AGU fall meeting abstracts","issued":{"date-parts":[[2022,12]]},"number":"V42B-05","page":"V42B-05","title":"Experiments on multiblast craters: Probing transient crater depths in multi-explosion events","type":"paper-conference","volume":"2022"}, 18 {"id":"gfs10","abstract":"We present results of experiments that use small chemical explosive charges buried in layered aggregates to simulate the effects of subsurface hydrothermal and phreatomagmatic explosions at varying depths and lateral locations, extending earlier experimental results that changed explosion locations only along a vertical axis. The focus is on the resulting crater size and shape and subcrater structures. Final crater shapes tend to be roughly circular if subsurface explosion epicenters occur within each others footprints (defined as the plan view area of reference crater produced by a single explosion of a given energy, as predicted by an empirical relationship). Craters are elongate if an epicenter lies somewhat beyond the footprint of the previous explosion, such that their footprints overlap, but if epicenters are too far apart, the footprints do not overlap and separate craters result. Explosions beneath crater walls formed by previous blasts tend to produce inclined (laterally directed) ejecta jets, while those beneath crater centers are vertically focused. Lateral shifting of explosion sites results in mixing of subcrater materials by development of multiple subvertical domains of otherwise pure materials, which progressively break down with repeated blasts, and by ejection and fallback of deeper-seated material that had experienced net upward displacement to very shallow levels by previous explosions. A variably developed collar of material that experienced net downward displacement surrounds the subvertical domains. The results demonstrate key processes related to mixing and ejection of materials from different depths during an eruptive episode at a maar-diatreme volcano as well as at other phreatomagmatic and hydrothermal explosion sites.","author":[{"family":"Valentine","given":"Greg A."},{"family":"Graettinger","given":"Alison H."},{"family":"Macorps","given":"Élodie"},{"family":"Ross","given":"Pierre-Simon"},{"family":"White","given":"James D. L."},{"family":"Döhring","given":"Érika"},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs10","container-title":"Bulletin of Volcanology","DOI":"10.1007/s00445-015-0901-7","ISSN":"0258-8900","issue":"3","issued":{"date-parts":[[2015]]},"language":"English","title":"Experiments with vertically and laterally migrating subsurface explosions with applications to the geology of phreatomagmatic and hydrothermal explosion craters and diatremes","type":"article-journal","volume":"77"}, 19 {"id":"gfs11","abstract":"Most volcanic explosions leave a crater in the surface around the center of the explosion. Such craters differ from products of single events like meteorite impacts or those produced by military testing because they typically result from multiple, rather than single, explosions.Here we analyze the evolution of experimental craters that were created by several detonations of chemical explosives in layered aggregates. An empirical relationship for the scaled crater radius as a function of scaled explosion depth for single blasts in flat test beds is derived from experimental data, which differs from existing relations and has better applicability for deep blasts. A method to calculate an effective explosion depth for non-flat topography (e.g. for explosions below existing craters) is derived, showing how multi-blast crater sizes differ from the single blast case. Sizes of natural caters (radii, volumes) are not characteristic of the number of explosions, nor therefore of the total acting energy, that formed a crater. Also the crater size is not simply related to the largest explosion in a sequence, but depends upon that explosion and the energy of that single blast and on the cumulative energy of all blasts that formed a crater. The two energies can be combined to form an effective number of explosions that is characteristic for the crater evolution. The multi-blast crater size evolution has implications on the estimates of volcanic eruption energies, indicating that it is not correct to estimate explosion energy from crater size using previously published relationships that were derived for single blast cases.","author":[{"family":"Sonder","given":"I."},{"family":"Graettinger","given":"Alison H."},{"family":"Valentine","given":"G. A."}],"citation-key":"gfs11","container-title":"Journal of Geophysical Research, Solid Earth","container-title-short":"JGR Solid Earth","DOI":"10.1002/2015JB012018","ISSN":"2169-9356","issue":"9","issued":{"date-parts":[[2015]]},"page":"6141-6158","title":"Scaling multiblast craters: general approach and application to volcanic craters","type":"article-journal","volume":"120"}, 20 {"id":"gfs12","abstract":"The volume, grain size, and depositional facies of material deposited outside an explosion crater, ejecta, are sensitive to the depth of the explosion, the explosion energy, and the presence or absence of a crater before the explosion. We detonate buried chemical explosives as an analog for discrete volcanic explosions in experiments to identify unique characteristics of proximal, medial, and distal ejecta facies and their distribution from a range of scaled depths in undisturbed and cratered ground. Ejecta are here discussed in terms of three facies: (1) proximal ejecta, which form a constructional landform around a crater; (2) medial ejecta, which form a continuous sheet deposit that thins much more gradually with distance; and (3) distal ejecta that are deposited as isolated clasts. The extent of proximal ejecta away from the crater, relative to crater size, is not sensitive to scaled depth, but the volume proportion of proximal ejecta to the total ejecta deposit is sensitive to the presence of a crater and scaled depth. Medial ejecta distribution and volume contributions are both sensitive to the presence of a crater and to scaled depth. Distal ejecta distance is dependent on scaled depth and the presence of a crater, while the volume proportion of distal ejecta is less sensitive to scaled depth or presence of a crater. Experimental facies and deposit structures inferred from observations of jet dynamics are used to suggest facies associations anticipated from eruptions dominated by explosions of different scaled depth configurations. We emphasize that significant differences in tephra ring deposits can result from the effects of scaled depth and preexisting craters on ejecta dynamics, and are not necessarily related to fundamental differences in explosion mechanisms or degree of magma fragmentation.","author":[{"family":"Graettinger","given":"A. H."},{"family":"Valentine","given":"G. A."},{"family":"Sonder","given":"I."},{"family":"Ross","given":"P.-S."},{"family":"White","given":"J. D. L."}],"citation-key":"gfs12","container-title":"Bulletin of Volcanology","container-title-short":"Bull. Volcanol.","DOI":"10.1007/s00445-015-0951-x","ISSN":"1432-0819","issue":"8","issued":{"date-parts":[[2015]]},"page":"1-12","title":"Facies distribution of ejecta in analog tephra rings from experiments with single and multiple subsurface explosions","type":"article-journal","volume":"77"}, 21 {"id":"gfs14","abstract":"While the relationship between the host-substrate properties and the formation of maar-diatreme volcanoes have been investigated in the past, it remains poorly understood. In order to establish the effects of the qualitative host-substrate properties on crater depth, diameter, morphological features, and sub-surface structures, we present a comparison of four campaigns of experiments that used small chemical explosives buried in various geological media to simulate the formation of maar-diatremes. Previous results from these experiments have shown that primary variations in craters and sub-surface structures are related to the scaled depth (physical depth divided by cube root of blast energy). Our study reveals that single explosions at optimal scaled depths in stronger host materials create the largest and deepest craters with steep walls and the highest crater rims. For single explosions at deeper than optimal scaled depths, the influence of material strength is less obvious and non-linear for crater depth, and non-existent for crater diameter, within the range of the experiments. For secondary and tertiary blasts, there are no apparent relationships between the material properties and the crater parameters. Instead, the presence of pre-existing craters influences the crater evolution. A general weakening of the materials after successive explosions can be observed, suggesting a possible decrease in the host-substrate influence even at optimal scaled depth. The results suggest that the influence of the host-substrate properties is important only in the early stage of a maar-diatreme (neglecting post-eruptive slumping into the open crater) and decreases as explosion numbers increase. Since maar-diatremes reflect eruptive histories that involve tens to hundreds of individual explosions, the influence of initial substrate properties on initial crater processes could potentially be completely lost in a natural system.","author":[{"family":"Macorps","given":"Élodie"},{"family":"Graettinger","given":"Alison H."},{"family":"Valentine","given":"Greg A."},{"family":"Ross","given":"Pierre-Simon"},{"family":"White","given":"James D. L."},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs14","container-title":"Bulletin of Volcanology","container-title-short":"Bull. Volcanol.","DOI":"10.1007/s00445-016-1013-8","issue":"4","issued":{"date-parts":[[2016,3]]},"title":"The effects of the host-substrate properties on maar-diatreme volcanoes: experimental evidence","type":"article-journal","volume":"78"}, 22 {"id":"gfs16","abstract":"Circumferential variation in sorting, thickness, granulometry, and componentry of tephra ring deposits can result from instabilities in the eruptive jet and interactions with the confining crater. Jet instabilities result in fingers of high particle concentrations that form deposits radiating away from a crater, referred to as rays. Two major types of rayed deposits are described from subsurface explosion experiments: (1) symmetrical rayed deposits with an axisymmetric ejecta blanket, which result from vertically directed eruptive jets and (2) zones of rays that extend out from sectors of a crater, with an asymmetrical proximal ejecta skirt, that result from inclined jets. Variations within each group are also associated with variations in the explosion depth relative to the energy of the explosion. Although the surface morphology of rays is likely to be lost in natural tephra rings due to overlapping deposits of numerous explosions, rayed deposits are expected to be preserved in cross section as lenses of relatively coarse and poorly sorted material compared to surrounding deposits. Asymmetrical deposits of inclined jets are anticipated to be particularly distinctive. The experimental facies associations indicate that these deposits would be easily distinguished, given sufficient exposure, from other heterogeneities caused by wind influence, collapse of the crater rim, or the influence of topography on density currents. These experimental results can also be used to further the discussion of deposits from inclined jets from other explosion scenarios, such as Vulcanian blasts and hydrothermal explosions. The experimental rayed deposits described here indicate that the classic interpretation of clast concentration zones in tephra ring deposits must be reevaluated.","author":[{"family":"Graettinger","given":"Alison H."},{"family":"Valentine","given":"Greg A."},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs16","container-title":"Journal of Volcanology and Geothermal Research","container-title-short":"J. Volcanol. Geotherm. Res.","DOI":"10.1016/j.jvolgeores.2015.10.019","issued":{"date-parts":[[2015]]},"page":"61-69","title":"Circum-crater variability of deposits from discrete, laterally and vertically migrating volcanic explosions: experimental evidence and field implications","type":"article-journal","volume":"308"}, 23 {"id":"gfs17","abstract":"Eruptions through debris-filled vents produce deposits containing magmatic juvenile lithic and recycled clasts. Recycled clasts are exposed to multiple transportation and fragmentation events. We used experiments with multiple subsurface explosions to track clasts and highlight dominant recycling processes in eruptions through analog debris-filled vents. Recycled clasts include those that fall back into and reside in the vent for extended time periods and those that return to the vent through crater growth or collapse. Clasts are recycled by any combination of lofting and fallback of material in the crater by explosion jets, mixing and churning of material at depth in the debris fill, and redistribution of extra-crater deposits by explosion-induced excavation or slumping. We compare experimental processes with natural deposits that preserve recycling signatures from discrete explosions through debris-filled vents such as maar-diatremes, Strombolian vents, and hydrothermal craters. Clasts may not preserve textures diagnostic of their complete recycling histories, but can be used to infer if that history occurred in part in the vent debris or in the eruptive jet. Experiment results and natural deposits suggest that for volcanic craters that undergo multiple explosions, clasts likely undergo some form of recycling before final deposition outside the craters. The underestimation of recycled clast contributions to deposits can lead to inaccurate estimates of thermal budgets and eruption processes.","author":[{"family":"Graettinger","given":"Alison H."},{"family":"Valentine","given":"Greg A."},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs17","container-title":"Geology","DOI":"10.1130/G38081.1","issued":{"date-parts":[[2016,8]]},"page":"G38081.1","title":"Recycling in debris-filled volcanic vents","type":"article-journal"}, 24 {"id":"gfs18","abstract":"Abstract The knowledge of the cooling time scales of pyroclasts, in conditions of free- to forced-convection, is of paramount importance in microtextural analysis, development of welded deposits, and in eruption column and pyroclast flow modeling. We performed cooling experiments of heated rock inside a cylindrical wind tunnel under a range of air-speeds. In order to estimate the heat transfer coefficients, we modeled the transient temperature distribution in the sample with temperature-dependent thermal diffusivity and heat capacity, which were obtained from Laser Flash measurements. For air-speeds up to 15 m s−1 and for sample temperatures up to 1110 ° C, a Nusselt-Reynolds (Nu-Re) relationship up to Re = 3 ×10⁴ is established in this study. We find that the dependency of heat loss on size is particularly important for pyroclasts larger than ∼ 1 mm. We also find that the cooling time scales of pyroclasts could be large enough to cause post-fragmentation modification of clast microtextures. We further show that a few centimeter size clast develops a solid thin crusts with a molten core within timescales of a few minutes, and therefore may inhibit post-depositional welding.","author":[{"family":"Moitra","given":"Pranabendu"},{"family":"Sonder","given":"Ingo"},{"family":"Valentine","given":"Greg A."}],"citation-key":"gfs18","container-title":"Geochemistry, Geophysics, Geosystems","container-title-short":"Geochem. Geophys. Geosyst.","DOI":"10.1029/2018GC007510","issue":"10","issued":{"date-parts":[[2018,10]]},"page":"3623-3636","title":"Effects of size and temperature-dependent thermal conductivity on the cooling of pyroclasts in air","type":"article-journal","volume":"19"}, 25 {"id":"gfs19","abstract":"Recent work is changing our understanding of phreatomagmatic maar-diatreme eruptions and resulting deposits. In previous models, explosions were often inferred to take place only at the base of a diatreme, with progressive downward migration due to a cone of depression in the host aquifer. However, diatremes themselves contain much water that is heterogeneously distributed, and field evidence supports the existence of explosion sites at many vertical and lateral locations within them. Crater sizes have been used to estimate explosion energies, but this only works for single-explosion craters where the depth of explosion is independently known, and has limited value for multi-explosion maar-diatremes. Deep-seated lithic clasts in tephra ring beds have been taken to indicate the depth of the explosion that produced that bed. However, only relatively shallow explosions actually vent to the surface, and deep-seated lithics are gradually brought to shallow depths through step-wise mixing of multiple subsurface explosions. Grain-size of tephra-ring deposits is often inferred to indicate fragmentation efficiency. However, other factors strongly influence deposit grain size, including the scaled depth of an explosion and the interaction of an erupting jet with topography around a vent (e.g., crater), along with long recognized effects of mechanical properties of host rocks and recycling within the vent/diatreme. These insights provide a foundation for future research into this important volcano type.","author":[{"family":"Valentine","given":"Greg A."},{"family":"White","given":"James D. L."},{"family":"Ross","given":"Pierre-Simon"},{"family":"Graettinger","given":"Alison H."},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs19","container-title":"Frontiers in Earth Science","container-title-short":"Front. Earth Sci.","DOI":"10.3389/feart.2017.00068","issued":{"date-parts":[[2017,8]]},"title":"Updates to concepts on phreatomagmatic maar-diatremes and their pyroclastic deposits","type":"article-journal","volume":"5"}, 26 {"id":"gfs2","abstract":"Craters at many volcanoes, including most maars, are formed by multiple subsurface explosions. Experiments compared the crater formed by a single large, buried explosion, with craters formed by multiple explosions with the same cumulative energy. Explosive charges were detonated in pads composed of layered aggregates, in three configurations: (1) a single large charge buried near its optimal crater excavation depth; (2) three charges, each with 1/3 the energy of the first one, buried at approximately the same depth with respect to the original pad surface; (3) the same three charges buried successively deeper. Final crater size in the multiple explosion cases is not a good indicator of the energy of individual explosions. However, crater morphology, and ejecta volume and distribution can be good indicators of explosion energy and depth. These results directly impact the estimate of the energy released by past maar eruptions and future hazard assessments.","author":[{"family":"Valentine","given":"Greg A."},{"family":"White","given":"James D. L."},{"family":"Ross","given":"Pierre-Simon"},{"family":"Amin","given":"Jamal"},{"family":"Taddeucci","given":"Jacopo"},{"family":"Sonder","given":"Ingo"},{"family":"Johnson","given":"Peter J."}],"citation-key":"gfs2","container-title":"Geophysical Research Letters","container-title-short":"Geophys. Res. Lett.","DOI":"10.1029/2012GL053716","issued":{"date-parts":[[2012]]},"page":"L20301","title":"Experimental craters formed by single and multiple buried explosions and implications for maar-diatreme volcanoes","type":"article-journal","volume":"39"}, 27 {"id":"gfs21","abstract":"Interaction of magma with ground or surface water can lead to explosive phreatomagmatic eruptions. Questions of this process center on effects of system geometry, length- and time scales, and these necessitate experiments at larger scale than previously conducted in order to investigate the thermo-hydraulic escalation behavior of rapid heat transfer. Previous experimental work either realized melt-water interaction at similar meter-scales, using a thermite-based magma analog in a confining vessel, or on smaller scale using ≈0.4kg remelted volcanic rock in an open crucible, with controlled premix and a ≈5J kinetic energy trigger event. The new setup uses 55kg melt for interaction, and the timing and location of the magma-water premix can be controlled on a scale up to 1 m. A trigger mechanism is a falling hammer that drives a plunger into the melt (≈28J kinetic energy). Results show intense interaction (Lmax⩾0.25m2) at relatively low magma/water mass ratio. A video analysis quantifies rate and amount of melt ejection and compares results with those using the same melt in the smaller scale setup. Experiments show that on the meter scale intense interaction can start spontaneously without an external trigger if the melt column above the initial mixing location is larger than 0.3m. Experiments suggest that buoyant rise of water domains in a melt column, could promote explosive interaction. We assess interaction scenarios between introduced water domains and a magma column, some of which could result in eruptions of Strombolian style, promoting brecciation and incorporation of wall rock debris into a magma column.","author":[{"family":"Sonder","given":"Ingo"},{"family":"Harp","given":"Andrew G."},{"family":"Graettinger","given":"Alison H."},{"family":"Moitra","given":"Pranabendu"},{"family":"Valentine","given":"Greg A."},{"family":"Büttner","given":"Ralf"},{"family":"Zimanowski","given":"Bernd"}],"citation-key":"gfs21","container-title":"Journal of Geophysical Research, Solid Earth","container-title-short":"J. Geophys. Res. Solid Earth","DOI":"10.1029/2018jb015682","issue":"12","issued":{"date-parts":[[2018,12]]},"page":"10597-10615","title":"Meter-scale experiments on magma-water interaction","type":"article-journal","volume":"123"}, 28 {"id":"gfs22","abstract":"One mechanism for generating lahars at volcanoes experiencing unrest is the disruption of internal aquifers. These disruptions can trigger releases of large quantities of groundwater. An example of such aquifer disruption occurred at Nevado del Huila Volcano, Colombia, during February and April 2007 when large fractures formed across the summit area of the volcano and lahars were emitted from them. Previous work interpreted that lahar volumes could not be accounted for by melted glacial snow or precipitation, and by elimination suggested that the primary water source was groundwater. Conceptual models have been developed for perched, confined aquifers that have been heated and pressurized by magma intrusions, followed by sudden pressure release and water emission during fracture formation. We consider an alternative end member wherein water release from large fissures at volcanoes is driven by simple gravity drainage. We apply numerical modeling to quantify water discharge from the porous medium surrounding a fissure with a low-elevation free exit. If a long fracture with high vertical extent (on the order of hundreds of meters) intersects a highly connected saturated porous medium, large volumes (on order 103 m3/m of crack length) of water may be released within tens of minutes. The drainage rates from the model may be adequate to account for the Nevado del Huila events if the medium surrounding the crack contains a large volume of water and has high horizontal permeability. This simple but poorly understood mechanism can present a hazard on its own or compound other processes releasing water from volcanoes.","author":[{"family":"Johnson","given":"Peter"},{"family":"Valentine","given":"Greg A."},{"family":"Stauffer","given":"Phil H."},{"family":"Lowry","given":"C. S."},{"family":"Sonder","given":"Ingo"},{"family":"Pulgarín","given":"B. A."},{"family":"Santacoloma","given":"C. C."},{"family":"Agudelo","given":"A."}],"citation-key":"gfs22","container-title":"Bulletin of Volcanology","container-title-short":"Bull. Volcanol.","DOI":"10.1007/s00445-018-1214-4","issue":"4","issued":{"date-parts":[[2018,3]]},"title":"Groundwater drainage from fissures as a source for lahars","type":"article-journal","volume":"80"}, 29 {"id":"gfs24","abstract":"The cooling rate of magma in the presence of external water during phreatomagmatic and submarine eruptions is one of the key parameters governing non-explosive to explosive magma fragmentation and eruption transitions, but remains poorly constrained. Combining results from laboratory experiments with realistic eruptive temperatures of magma cooling in ambient water of variable temperatures, and numerical modeling of transient heat transfer, we find that magma-to-water heat flux can be up to W m−2. The experiments exhibit two distinct water boiling regimes: A film-boiling regime defined by the presence of a coherent water vapor film between magma surface and ambient water, and a nucleate boiling regime below a critical magma surface temperature (known as the Leidenfrost temperature), where the vapor film breaks and numerous bubbles form at the magma-water interface. In general the vapor film was stable in our experiments for time scales of ≤ 5 s, indicating that this might be a limiting factor in pre-explosion magma-water mixing for energetic molten fuel-coolant interaction and explosive volcanic eruptions. The time scale of vapor film stability increases and the Leidenfrost temperature (1223 to 948 K) decreases with increasing water temperature (276 to 366 K). We show that for the empirically obtained large heat flux to external water, the cooling rate of magma can reach up to 106 K/s at length scales of few microns, thus magma may undergo fine fragmentation due to quench-induced large thermal stresses. Our experimental and modeling results demonstrate that the time scales of various water boiling regimes, and erupting magma and ambient water temperatures determine the magma-to-water heat transfer rates, which in turn determine the transition to explosivity under subaqueous eruption conditions.","author":[{"family":"Moitra","given":"Pranabendu"},{"family":"Sonder","given":"Ingo"},{"family":"Valentine","given":"Greg A."}],"citation-key":"gfs24","container-title":"Earth and Planetary Science Letters","DOI":"10.1016/j.epsl.2020.116194","issued":{"date-parts":[[2020,3,10]]},"page":"116194","title":"The role of external water on rapid cooling and fragmentation of magma","type":"article-journal","volume":"537"}, 30 {"id":"gfs26","abstract":"Blasting experiments were performed that investigate multiple explosions that occur in quick succession in unconsolidated ground and their effects on host material and atmosphere. Such processes are known to occur during phreatomagmatic eruptions at various depths, lateral locations, and energies. The experiments follow a multi-instrument approach in order to observe phenomena in the atmosphere and in the ground, and measure the respective energy partitioning. The experiments show significant coupling of atmospheric (acoustic)- and ground (seismic) signal over a large range of (scaled) distances (30–330 m, 1–10 m J−1/3). The distribution of ejected material strongly depends on the sequence of how the explosions occur. The overall crater sizes are in the expected range of a maximum size for many explosions and a minimum for one explosion at a given lateral location. As previous research showed before, peak atmospheric over-pressure decays exponentially with scaled depth. An exponential decay rate of??? was measured. At a scaled explosion depth of 4 × 10−3 m J−1/3 ca. 1% of the blast energy is responsible for the formation of the atmospheric pressure pulse; at a more shallow scaled depth of 2.75 × 10−3 m J−1/3 this ratio lies at ca. 5.5%–7.5%. A first order consideration of seismic energy estimates the sum of radiated airborne and seismic energy to be up to 20% of blast energy. Finally, the transient cavity formation during a blast leads to an effectively reduced explosion depth that was determined. Depth reductions of up to 65% were measured.","author":[{"family":"Sonder","given":"Ingo"},{"family":"Graettinger","given":"Alison H."},{"family":"Neilsen","given":"Tracianne B."},{"family":"Matoza","given":"Robin S."},{"family":"Taddeucci","given":"Jacopo"},{"family":"Oppenheimer","given":"Julie"},{"family":"Lev","given":"Einat"},{"family":"Tsunematsu","given":"Kae"},{"family":"Waite","given":"Gregory P."},{"family":"Valentine","given":"Greg A."},{"family":"Befus","given":"Kenneth S."}],"citation-key":"gfs26","container-title":"Journal of Geophysical Research: Solid Earth","container-title-short":"JGR Solid Earth","DOI":"10.1029/2022JB023952","ISSN":"2169-9313, 2169-9356","issue":"8","issued":{"date-parts":[[2022,8]]},"title":"Experimental multiblast craters and ejecta — seismo-acoustics, jet characteristics, craters, and ejecta deposits and implications for volcanic explosions","type":"article-journal","volume":"127"}, 31 {"id":"gfs27","abstract":"Investigating the conditions behind the formation of pyroclast textures and lava flow morphologies is important to understand the dynamics of submarine volcanic eruptions, which are hard to observe. The development of clast textures and lava morphologies depends on the competing effects of their eruption rates and the rates of solidification. While eruption rates are governed by subsurface magmatic processes, the solidification time scales depend on the rate of heat loss from lava to the external water. However, the effect of the speed of lava flow or clast on their solidification time scales under two phase water boiling conditions is poorly constrained. Using laboratory experiments with re-melted igneous rocks, we investigate the effect of the relative motion between lava and external water on its cooling time scale. We use a range of water speed (0-12.5 cm s−1) in our experiments while keeping our sample stationary to simulate a range of relative speed between lava and ambient water. Using transient heat transfer modeling, we find that heat flux from the surface of sample to the external water overall increases with increasing water speed. We find heat transfer coefficients of up to ∼1.72 × 103 Wm-2 K-1. The implications of high heat flux on the formation of solid lava crust under submarine conditions are discussed.","author":[{"family":"Moitra","given":"Pranabendu"},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs27","container-title":"Journal of Geophysical Research: Solid Earth","container-title-short":"JGR Solid Earth","DOI":"10.1029/2022JB024665","ISSN":"2169-9313, 2169-9356","issue":"8","issued":{"date-parts":[[2022,8]]},"language":"en","title":"Vapor bubbles and velocity control on the cooling rates of lava and pyroclasts during submarine eruptions","type":"article-journal","volume":"127"}, 32 {"id":"gfs28","abstract":"Primary magma fragmentation in “fluid-dominated” (as opposed to “ash-dominated”) lava fountains involves the hydrodynamic breakup of a jet of magma. Lava fountains partly resemble industrial liquid jets issued from a nozzle into a quiescent atmosphere, on which there is a vast literature. Depending on the internal liquid properties, nozzle diameter and ejection velocity, liquid jet breakup in industrial applications occurs in four regimes: (I) coarse laminar breakup (Rayleigh regime); (II) transition region between laminar and turbulent breakup (first wind-induced regime); (III) turbulent breakup at the jet surface and unstable but intact liquid core (second wind-induced regime); (IV) fully turbulent fine spray (atomization regime).\n\nDuctile magma breakup associated with regimes II, III and IV have been reproduced during the initial expansion of experimental magma fragmentation pulses as part of this study. In each experiment, volcanic rocks were re-melted at 1200 °C, then fragmented through the injection of compressed argon gas within a few tens of milliseconds. Three compositions were used: olivine-melilitite, alkali basalt, and basaltic trachy-andesite. Each composition was ejected at 3 and 10 MPa gas driving pressure, yielding exit velocities between 11–13 and 33–44 m/s, respectively. The ultramafic magma ejected at high speed developed quickly into a fully developed spray (regime IV), whereas the basaltic trachy-andesite ejected at low-speed initially expanded as a coherent magma mass before breaking into coarse domains (regime II). The observed variability among the experiments is linked to the relative balance among surface tension, viscosity, density, jet diameter and ejection velocity of the magma versus external aerodynamic effects acting on the jet surface. These factors, particularly viscosity and exit velocity, are also likely to control jet breakup regimes in natural lava fountains and some Strombolian pulses.","accessed":{"date-parts":[[2022,7,8]]},"author":[{"family":"Comida","given":"Pier Paolo"},{"family":"Ross","given":"Pierre-Simon"},{"family":"Zimanowski","given":"Bernd"},{"family":"Büttner","given":"Ralf"},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs28","container-title":"Journal of Volcanology and Geothermal Research","container-title-short":"Journal of Volcanology and Geothermal Research","DOI":"10.1016/j.jvolgeores.2022.107609","ISSN":"03770273","issued":{"date-parts":[[2022,9]]},"language":"en","page":"107609","source":"DOI.org (Crossref)","title":"Liquid jet breakup regimes in lava fountains","type":"article-journal","volume":"429"}, 33 {"id":"gfs29","abstract":"Pre-mixing of magma and external water plays a key role in driving explosive phreatomagmatic and submarine volcanic eruptions. A thin film of water vapor forms at the magma–water interface as soon as hot magma comes in direct contact with the cold water (Leidenfrost effect). The presence of a stable vapor film drives efficient mixing and mingling between magma and water, as well as magma and wet and water-saturated sediments. Such mixing occurs before explosive molten fuel–coolant type interactions. Using high-temperature laboratory experiments, we investigate the effect of magma and water temperatures on the stability of vapor film, which has not been performed systematically for a magmatic heat source. The experiments were performed with re-melted volcanic rock material, from which spherically-shaped rock samples were produced. These samples were heated to 1,110°C and then submerged in a water pool with a constant temperature (3–93°C). The experiments were recorded on video, and, synchronously, sample and water temperatures were measured using thermocouples. The time-dependent thickness of the vapor film was measured from the video material. The vapor film tends to oscillate with time on the order of 10<sup>2</sup> Hz. We find that the vertical collapse rates of vapor films along the sample–water interfaces are 13.7 mm s<sup>−1</sup> and 4.2 mm s<sup>−1</sup> for water temperatures of 3.0°C and 65°C, respectively. For a given initial sample temperature, the thickness and stability time scales decrease with decreasing water temperature, which has implications for the efficiency of pre-mixing required for explosive eruptions. Using thermodynamics and previously measured material parameters, it is shown that a sudden collapse of the vapor film can start brittle fragmentation of the melt and thus serves as the starting point of thermohydraulic explosions.","author":[{"family":"Sonder","given":"Ingo"},{"family":"Moitra","given":"Pranabendu"}],"citation-key":"gfs29","container-title":"Frontiers in Earth Science","DOI":"10.3389/feart.2022.983112","ISSN":"2296-6463","issued":{"date-parts":[[2022]]},"title":"Experimental constraints on the stability and oscillation of water vapor film–a precursor for phreatomagmatic and explosive submarine eruptions","type":"article-journal","volume":"10"}, 34 {"id":"gfs3","abstract":"Maar-diatreme eruptions are hazardous to people and infrastructure, and are also linked to the formation of the kimberlitic variety of diatremes, which is important economically. Processes occurring in the subsurface diatreme and their relation to surface eruptions are not yet well understood. We conducted field-scale experiments using analogue materials to shed more light on these processes, especially the formation of the proto-diatreme during the first explosions of a maar eruption. Specifically, a series of buried explosions in a prepared, layered substrate (pads) produced craters, extra-crater deposits and sub-crater deposits analogous to volcanic maar craters, tephra rings and incipient diatremes. Post-explosion substrate excavation revealed that single large explosions produce sub-crater deposits extending nearly to the crater-rim crest. The same energy divided into three blasts, either co-located or at different depths with the same epicenter, produced narrower and sometimes deeper sub-crater deposits even though the final sizes of the craters were similar to that produced by the single large blast. The sub-crater deposits have an upper zone with domains from different substrate depths, and an underlying zone distinguished primarily by being more loosely packed than the original substrate. Videos show surface motion extending beyond the post-shot crater rim, and largely vertical ejection and fallback of material into the footprint of these deposits, especially for the explosions that occurred below optimal depth of burial. We infer that much of the loosely packed material was disassembled, vertically transported to different heights during the explosions, then fell back without significant relative lateral movement of grains. However, subvertical fallback did produce apparent cross-cutting structures in shallow sub-crater deposits. One explosion ejected material from the deepest substrate horizon, but it was redeposited only within the crater and is unrepresented in the ejecta rim. Implications of the experiments for maar-diatreme volcanoes, including some kimberlite pipes, are as follows: (1) vertical focusing of deep explosions in the diatreme explains the deficit of deep wallrock lithics observed at maar volcanoes; (2) direct vertical fallback is possibly an important process forming diatreme deposits, especially during the earliest stages; (3) even in our limited simulation the number and scaled depth of explosions clearly affect proto-diatreme size and structure.","author":[{"family":"Ross","given":"Pierre-Simon"},{"family":"White","given":"James D. L."},{"family":"Valentine","given":"Greg A."},{"family":"Taddeucci","given":"Jacopo"},{"family":"Sonder","given":"Ingo"},{"family":"Andrews","given":"Robin G."}],"citation-key":"gfs3","container-title":"Journal of Volcanology and Geothermal Research","container-title-short":"J. Volcanol. Geotherm. Res.","DOI":"10.1016/j.jvolgeores.2013.05.005","issued":{"date-parts":[[2013]]},"page":"1-12","title":"Experimental birth of a maar-diatreme volcano","type":"article-journal","volume":"260"}, 35 {"id":"gfs5","abstract":"Most volcanic eruptions occur in craters formed by previous activity. The presence of a crater implies specific confinement geometries, variably filled by loose fragmental deposits, which are expected to exert a strong, yet poorly studied, control on the violent gas expansion that drives the eruption. Here we analyze patterns of ejection from buried explosions in analog experiments, in order to investigate how the presence of a crater and changes in explosion depth and intensity may affect the formation of eruptive ejecta jets. Results show that scaled depth (charge burial depth divided by the cubic root of charge energy) controls the velocity and, partly, spread angle of eruptive jets independently of the presence of a pre-existing crater. Conversely, for a fixed scaled depth, the presence of a pre-existing crater limits the development of a laterally expanding annulus of the jet. These results are directly applicable to interpretation of volcanic explosions.","author":[{"family":"Taddeucci","given":"J."},{"family":"Valentine","given":"G. A."},{"family":"Sonder","given":"I."},{"family":"White","given":"J. D. L."},{"family":"Ross","given":"P.-S."},{"family":"Scarlato","given":"P."}],"citation-key":"gfs5","container-title":"Geophysical Research Letters","container-title-short":"Geophys. Res. Lett.","DOI":"10.1002/grl.50176","ISSN":"1944-8007","issued":{"date-parts":[[2013]]},"page":"507-510","title":"The effect of pre-existing craters on the initial development of explosive volcanic eruptions: an experimental investigation","type":"article-journal","volume":"40"}, 36 {"id":"gfs7","abstract":"Basaltic maar-diatreme volcanoes, which have craters cut into preeruption landscapes (maars) underlain by downward-tapering bodies of fragmental material commonly cut by hypabyssal intrusions (diatremes), are produced by multiple subsurface phreatomagmatic explosions. Although many maar-diatremes have been studied, the link between explosion dynamics and the resulting deposit architecture is still poorly understood. Scaled experiments employed multiple buried explosions of known energies and depths within layered aggregates in order to assess the effects of explosion depth, and the morphology and compaction of the host on the distribution of host materials in resulting ejecta, the development of subcrater structures and deposits, and the relationships between them. Experimental craters were 1–2 m wide. Analysis of high-speed video shows that explosion jets had heights and shapes that were strongly influenced by scaled depth (physical depth scaled against explosion energy) and by the presence or absence of a crater. Jet properties in turn controlled the distribution of ejecta deposits outside the craters, and we infer that this is also reflected in the diverse range of deposit types at natural maars. Ejecta were dominated by material that originated above the explosion site, and the shallowest material was dispersed the farthest. Subcrater deposits illustrate progressive vertical mixing of host materials through successive explosions. We conclude that the progressive appearance of deeper-seated material stratigraphically upward in deposits of natural maars probably records the length and time scale for upward mixing through multiple explosions with ejection by shallow blasts, rather than progressive deepening of explosion sites in response to draw down of aquifers.","author":[{"family":"Graettinger","given":"Alison H."},{"family":"Valentine","given":"G. A."},{"family":"Sonder","given":"I."},{"family":"Ross","given":"P.-S."},{"family":"White","given":"J. D. L."},{"family":"Taddeucci","given":"J."}],"citation-key":"gfs7","container-title":"Geochem. Geophys. Geosys.","DOI":"10.1002/2013GC005198","ISSN":"1525-2027","issue":"3","issued":{"date-parts":[[2014]]},"page":"740-764","title":"Maar-diatreme geometry and deposits: Subsurface blast experiments with variable explosion depth","type":"article-journal","volume":"15"}, 37 {"id":"gfs8","abstract":"Infrasound and high-speed imaging during a series of field-scale buried explosions suggest new details about the generation and radiation patterns of acoustic waves from volcanic eruptions. We recorded infrasound and high-speed video from a series of subsurface explosions with differing burial depths and charge sizes. Joint observations and modeling allow the extraction of acoustic energy related to the magnitude of initial ground deformation, the contribution of gas breakout, and the timing of the fallback of displaced material. The existence and relative acoustic amplitudes of these three phases depended on the size and depth of the explosion. The results motivate a conceptual model that relates successive contributions from ground acceleration, gas breakout, and spall fallback to the acoustic amplitude and waveform characteristics of buried explosions. We place the literature on infrasound signals at Santiaguito Volcano, Guatemala, and Sakurajima and Suwonosejima Volcanoes, Japan, in the context of this model.","author":[{"family":"Bowman","given":"Daniel C."},{"family":"Taddeucci","given":"Jacopo"},{"family":"Kim","given":"Keehoon"},{"family":"Anderson","given":"Jacob F."},{"family":"Lees","given":"Jonathan M."},{"family":"Graettinger","given":"Alison H."},{"family":"Sonder","given":"Ingo"},{"family":"Valentine","given":"Greg A."}],"citation-key":"gfs8","container-title":"Geophysical Research Letters","container-title-short":"Geophys. Res. Lett.","DOI":"10.1002/2014GL059324","ISSN":"1944-8007","issue":"6","issued":{"date-parts":[[2014]]},"page":"1916-1922","title":"The acoustic signatures of ground acceleration, gas expansion, and spall fallback in experimental volcanic explosions","type":"article-journal","volume":"41"}, 38 {"id":"gfs9","abstract":"Subsurface phreatomagmatic explosions can result from the interaction of ascending magma with groundwater. Experiments over a wide range of energies show that for a given energy there is a depth below which an explosion will be contained within the subsurface (not erupt), and there is a corresponding shallower depth that will optimize ejecta dispersal. We combine these relationships with constraints on the energies of phreatomagmatic explosions at maar-diatreme volcanoes and show that most eruptions are likely sourced by explosions in the uppermost 200 m, and even shallower ones (¡100 m) are likely to dominate deposition onto tephra rings. Most explosions below 200 m will not erupt but contribute to formation of, and to the vertical mixing of materials within, a diatreme (vent structure), with only rare very high energy explosions between 200 and 500 m erupting. Similar constraints likely apply at other volcanoes that experience phreatomagmatic explosions.","author":[{"family":"Valentine","given":"Greg A."},{"family":"Graettinger","given":"Alison H."},{"family":"Sonder","given":"Ingo"}],"citation-key":"gfs9","container-title":"Geophysical Research Letters","container-title-short":"Geophys. Res. Lett.","DOI":"10.1002/2014GL060096","ISSN":"1944-8007","issue":"9","issued":{"date-parts":[[2014]]},"page":"3045-3051","title":"Explosion depths for phreatomagmatic eruptions","type":"article-journal","volume":"41"}, 39 {"id":"pvl27","abstract":"Basaltic melt drives most of earthq̊s volcanism. Understanding its rheology is crucial for any model of magma transport and volcanic eruption. Basaltic magma is generally treated as a quasi Newtonian liquid, but there are observations of Non-Newtonian behaviour. With a method, that allows measurement of Non-Newtonian viscosity of a representative melt (molten basaltic rock), we found a strong shear rate dependency of viscosity in a wide range of temperatures. The temperature-viscosity dependency indicates properties of the molten phase as the cause. The viscosity data are in good agreement with a power law model.","author":[{"family":"Sonder","given":"I."},{"family":"Büttner","given":"R."},{"family":"Zimanowski","given":"B."}],"citation-key":"pvl27","container-title":"Geophysical Research Letters","container-title-short":"Geophys. Res. Lett.","DOI":"10.1029/2005GL024240","issue":"2","issued":{"date-parts":[[2006,1]]},"page":"L02303","title":"Non-newtonian viscosity of basaltic magma","type":"article-journal","URL":"http://dx.doi.org/10.1029/2005GL024240","volume":"33"}, 40 {"id":"pvl28","abstract":"The release of kinetic energy during explosive volcanic eruptions is a key parameter for hazard assessment and civil defense. The explosive production of volcanic ash by intensive fragmentation of magma and host rocks represents a substantial part of this energy. For cases of explosive eruption where predominantly host rock was fragmented (phreatomagmatic eruptions) to form the major part of volcanic ash, rock mechanical parameters could be measured and fragmentation energies assigned. In cases where most of the produced ash is of juvenile origin (magmatic eruptions) a general method for the determination of fragmentation energy is still lacking. In this article we introduce a thermodynamic approach that relates grain size data of the produced ash deposits to shear rates acting during the deformation of magma. With the use of a standardized fragmentation experiment the physical parameters needed to determine the specific fragmentation energy and deformation history were measured. The experiment was calibrated and tested with two case histories of the Campi Flegrei volcanic field (southern Italy). Both eruptions are classified as “most probable worst-case scenarios” during the next period of activity, to be expected within the next 10–100 years. Using the experimentally determined specific fragmentation energies, the total mass of produced ash of each eruption, and assuming an energy dissipation as observed in the experiments, the total kinetic energy release of the worst-case Campi Flegrei eruptive events to come were calculated with 25 and 40 kt TNT equivalent.","author":[{"family":"Büttner","given":"R."},{"family":"Dellino","given":"P."},{"family":"Raue","given":"H."},{"family":"Sonder","given":"I."},{"family":"Zimanowski","given":"B."}],"citation-key":"pvl28","container-title":"Journal of Geophysical Research","container-title-short":"J. Geophys. Res.","DOI":"10.1029/2005JB003958","issued":{"date-parts":[[2006]]},"page":"B08204","title":"Stress induced brittle fragmentation of magmatic melts: Theory and experiments","type":"article-journal","URL":"http://dx.doi.org/10.1029/2005JB003958","volume":"111"}, 41 {"id":"pvl34","abstract":"Pyroclastic flows represent the most hazardous events of explosive volcanism, one striking example being the famous historical eruption of Vesuvius that destroyed Pompeii (AD 79). Much of our knowledge of the mechanics of pyroclastic flows comes from theoretical models and numerical simulations. Valuable data are also stored in the geological record of past eruptions, including the particles contained in pyroclastic deposits, but the deposit characteristics are rarely used for quantifying the destructive potential of pyroclastic flows. By means of experiments, we validate a model that is based on data from pyroclastic deposits. The model allows the reconstruction of the current's fluid-dynamic behaviour. Model results are consistent with measured values of dynamic pressure in the experiments, and allow the quantification of the damage potential of pyroclastic flows.","author":[{"family":"Dellino","given":"Pierfrancesco"},{"family":"Büttner","given":"Ralf"},{"family":"Dioguardi","given":"Fabio"},{"family":"Doronzo","given":"Domenico M."},{"family":"Volpe","given":"Luigi La"},{"family":"Mele","given":"Daniela"},{"family":"Sonder","given":"Ingo"},{"family":"Sulpizio","given":"Roberto"},{"family":"Zimanowski","given":"Bernd"}],"citation-key":"pvl34","container-title":"Earth and Planetary Science Letters","container-title-short":"Earth Planet. Sci. Lett.","DOI":"10.1016/j.epsl.2010.04.022","ISSN":"0012-821X","issue":"1–2","issued":{"date-parts":[[2010]]},"page":"314-320","title":"Experimental evidence links volcanic particle characteristics to pyroclastic flow hazard","type":"article-journal","URL":"http://www.sciencedirect.com/science/article/B6V61-50237HD-C/2/59170e45b9f033b4f1ad0773709cca4c","volume":"295"}, 42 {"id":"pvl36","abstract":"Compared to \"dry\" atmospheric eruption of magma or \"dry\" magma/rock contact, intensity and time scale of heat discharge from magma to the surroundings is strongly modified by an effective coolant: water or water-sediment mixes. In the case of subaqueous or subglacial eruptions magma-water contact must take place and can result in phreatomagmatic explosions. Even if no explosions occur, rapid cooling results in the formation of pyroclasts by thermal granulation. To study this process in detail, a short-term calorimeter was built for the direct measurement of the heat-flux from a magmatic melt to a coolant. Volcanic rocks from recent eruptions in Iceland were remelted and used to produce jets of melt poured into a coolant-filled container. Particles could be produced in a non-explosive process, that are practical identical to those from natural hyaloclastites. The process' fragmentation energy is about 10% of the total heat transferred from melt to coolant.","author":[{"family":"Schmid","given":"Andrea"},{"family":"Sonder","given":"Ingo"},{"family":"Seegelken","given":"Rolf"},{"family":"Zimanowski","given":"Bernd"},{"family":"Büttner","given":"Ralf"},{"family":"Gudmundsson","given":"Magnus Tumi"},{"family":"Oddsson","given":"Björn"}],"citation-key":"pvl36","container-title":"Geophysical Research Letters","container-title-short":"Geophys. Res. Lett.","DOI":"10.1029/2010GL044963","issue":"20","issued":{"date-parts":[[2010]]},"page":"L20311","title":"Experiments on the heat discharge at the dynamic magma-water-interface","type":"article-journal","URL":"http://dx.doi.org/10.1029/2010GL044963","volume":"37"}, 43 {"id":"pvl37","abstract":"A basic experimental study of the behavior of magma rheology was carried out on remelted volcanic rocks using wide gap viscometry. The complex composition of magmatic melts leads to complicated rheologic behavior which cannot be described with one simple model. Therefore, measurement procedures which are able to quantify non-Newtonian behavior have to be employed. Furthermore, the experimental apparatus must be able to deal with inhomogeneities of magmatic melts. We measured the viscosity of a set of materials representing a broad range of volcanic processes. For the lower viscous melts (low-silica compositions), non-Newtonian behavior is observed, whereas the high-silica melts show Newtonian behavior in the measured temperature and shear rate range (T = 1423 K - 1623 K, ̇γ=10⁻²s⁻¹ - 20 s⁻¹). The non-Newtonian materials show power-law behavior. The measured viscosities η and power-law indexes m lie in the intervals 8 Pas ≤η≤ 2103 Pas, 0.71 ≤m ≤ 1.0 (Grímsvötn basalt), 0.9 Pas ≤η≤350 Pas, 0.61 ≤m ≤ 0.93 (Hohenstoffeln olivine-melilitite), and 8 Pas ≤η≤ 1.5104 Pas, 0.55 ≤m ≤1.0 (Sommata basalt). Measured viscosities of the Newtonian high-silica melts lie in the range 104 Pas ≤η≤3 10⁵ Pas.","author":[{"family":"Hobiger","given":"Manuel"},{"family":"Sonder","given":"Ingo"},{"family":"Büttner","given":"Ralf"},{"family":"Zimanowski","given":"Bernd"}],"citation-key":"pvl37","container-title":"Journal of Volcanology and Geothermal Research","container-title-short":"J. Volcanol. Geotherm. Res.","DOI":"10.1016/j.jvolgeores.2010.11.020","ISSN":"0377-0273","issue":"1–2","issued":{"date-parts":[[2011]]},"page":"27-34","title":"Viscosity characteristics of selected volcanic rock melts","type":"article-journal","URL":"http://www.sciencedirect.com/science/article/B6VCS-51N228G-2/2/a34fbae3ec1dd4eafd70b05310ce91f4","volume":"200"}, 44 {"id":"pvl39","abstract":"The presence of water at volcanic vents can have dramatic effects on fragmentation and eruption dynamics, but little is known about how the presence of particulate matter in external water will further alter eruptions. Volcanic edifices are inherently “dirty” places, where particulate matter of multiple origins and grainsizes typically abounds. We present the results of experiments designed to simulate non-explosive interactions between molten basalt and various “coolants,” ranging from homogeneous suspensions of 0 to 30 mass% bentonite clay in pure water, to heterogeneous and/or stratified suspensions including bentonite, sand, synthetic glass beads and/or naturally-sorted pumice. Four types of data are used to characterise the interactions: (1) visual/video observations; (2) grainsize and morphology of resulting particles; (3) heat-transfer data from a network of eight thermocouples; and (4) acoustic data from three force sensors. In homogeneous coolants with b 10% bentonite, heat transfer is by convection, and the melt is efficiently fragmented into blocky particles through multiple thermal granulation events which produce associated acoustic signals. For all coolants with N 20% sediment, heat transfer is by forced convection and conduction, and thermal granulation is less efficient, resulting in fewer blocky particles, larger grainsizes, and weaker acoustic signals. Many particles are droplet-shaped or/and “vesicular,” containing bubbles filled with coolant. Both of these particle types indicate significant hydrodynamic magma–coolant mingling, and many of them are rewelded into compound particles. The addition of coarse material to heterogeneous suspensions further slows heat transfer thus reducing thermal granulation, and variable interlocking of large particles prevents efficient hydrodynamic mingling. This results primarily in rewelded melt piles and inefficient distribution of melt and heat throughout the coolant volume. Our results indicate that even modest concentrations of sediment in water will significantly limit heat transfer during non-explosive magma–water interactions. At high concentrations, the dramatic reduction in cooling efficiency and increase in mingling help to explain globular peperite, and provide information relevant to analyses of premixing associated with highly-explosive molten fuel–coolant interactions in debris-filled volcanic vents.","author":[{"family":"Schipper","given":"C. Ian"},{"family":"White","given":"James D. L."},{"family":"Zimanowski","given":"Bernd"},{"family":"Büttner","given":"Ralf"},{"family":"Sonder","given":"Ingo"},{"family":"Schmid","given":"Andrea"}],"citation-key":"pvl39","container-title":"Earth and Planetary Science Letters","container-title-short":"Earth Planet. Sci. Lett.","DOI":"10.1016/j.epsl.2011.01.010","issue":"3–4","issued":{"date-parts":[[2011]]},"page":"323-336","title":"Experimental interaction of magma and \"dirty\" coolants","type":"article-journal","URL":"http://dx.doi.org/10.1016/j.epsl.2011.01.010","volume":"303"}, 45 {"id":"pvl40","abstract":"Much of the volcanism on Earth takes place in subaqueous settings where magma has direct contact with a water reservoir of restricted or quasi unrestricted volume. In order to assess the intensity and time scale of non-explosive interaction of magmatic melts and water, experiments representing these settings were performed. Natural volcanic samples were remelted and poured as a continuous jet into a water-filled calorimeter where the melt interacts with its coolant. The rapid cooling results in granulation, i.e. brittle failure of the material. Granulation needs energy, which is taken from the thermal input of the hot melt. Energy used in granulation was found to require 5%–20% of the meltq̊s initial heat content. This energy loss fraction is insensitive to variations in coolant- and melt temperatures but instead depends on the meltq̊s thermo-mechanical properties. However analysis of the experimentally produced granulate indicates a strong correlation between the initial coolant temperature —i.e. the heat sink— and the grain-size distribution, but also shows variations due to material properties. The maximum of the grain-size distribution was determined to change from a diameter of 1 mm up to 4 mm due to coolant temperature increase. Properties of the heat source (melt) dominate the efficiency of the process, whereas both heat sink and source characteristics determine the products.","author":[{"family":"Sonder","given":"Ingo"},{"family":"Schmid","given":"Andrea"},{"family":"Seegelken","given":"Rolf"},{"family":"Zimanowski","given":"Bernd"},{"family":"Bütner","given":"Ralf"}],"citation-key":"pvl40","container-title":"Journal of Geophysical Research","container-title-short":"J. Geophys. Res.","DOI":"10.1029/2011JB008280","issue":"B9","issued":{"date-parts":[[2011,9]]},"page":"B09203","title":"Heat source or heat sink: What dominates behavior of non-explosive magma-water interaction?","type":"article-journal","URL":"http://dx.doi.org/10.1029/2011JB008280","volume":"116"}, 46 {"id":"pvl51","abstract":"Recent observations have shattered the long-held theory that deep-sea (¿500 m) explosive eruptions are impossible; however, determining the dynamics of unobserved eruptions requires interpretation of the deposits they produce. For accurate interpretation to be possible, the relative abilities of explosive magmatic degassing and non-explosive magma–water interaction to produce characteristic submarine volcaniclastic particles such as limu o Peleq̊ (bubble wall shards of glass) must be established. We experimentally address this problem by pouring remelted basalt (1300 ◦ C, anhydrous) into a transparent, water-filled reservoir, recording the interaction with a high-speed video camera and applying existing heat transfer models. We performed the experiments under moderate to high degrees of water subcooling (∼8 l of water at 58 and 3 ◦ C), with ∼0.1 to 0.15 kg of melt poured at ∼10−2 kg s−1 . Videos show the non-explosive, hydromagmatic blowing and bursting of isolated melt bubbles to form limu o Pele particles that are indistinguishable from those found in submarine volcaniclastic deposits. Pool boiling around growing melt bubbles progresses from metastable vapour film insulation, through vapour film retraction/collapse, to direct melt-water contact. These stages are linked to the evolution of melt-water heat transfer to verify the inverse relationship between vapour film stability and the degree of water subcooling. The direct contact stage in particular explains the extremely rapid quench rates determined from glass relaxation speedometry for natural limu. Since our experimentally produced limu is made entirely by the entrapping of ambient water in degassed basaltic melt, we argue that the presence of fast-quenched limu o Pele in natural deposits is not diagnostic of volatile-driven explosive eruptions. This must be taken into account if submarine eruption dynamics are to be accurately inferred from the deposits and particles they produce.","author":[{"family":"Schipper","given":"C. Ian"},{"family":"Sonder","given":"Ingo"},{"family":"Schmid","given":"Andrea"},{"family":"White","given":"James D. L."},{"family":"Dürig","given":"Tobias"},{"family":"Zimanowski","given":"Bernd"},{"family":"Büttner","given":"Ralf"}],"citation-key":"pvl51","container-title":"Geophysical Journal International","container-title-short":"Geophys. J. Int.","DOI":"10.1093/gji/ggs099","issue":"3","issued":{"date-parts":[[2013]]},"page":"1109-1115","title":"Vapour dynamics during magma-water interaction experiments: Hydromagmatic origins of submarine volcaniclastic particles (limu o Pele)","type":"article-journal","URL":"http://dx.doi.org/10.1093/gji/ggs099","volume":"192"}, 47 {"id":"sonder2018NSFLarge2021","abstract":"A collection of datasets which were recorded at the 2018 NSF Large Scale Experiment Multiblast workshop on volcanic hazards.\n\nThe workshop aimed to facilitate interdisciplinary collaboration and improve field-scale testing of monitoring methods and models. The workshop had 47 participants from US-based and international institutions. Read some more details in this EOS article or a full manuscript which is currently in review. <strong>attention</strong>: This dataset is UNDER CONSTRUCTION. It is close to, but not absolutely complete. We will publish version 1.0 once the accompanying JGR manuscript has been approved for publication. All data is provided in several zip archives, and small files containing metadata and descriptions. Large data chunks are separated into 'pads' (1–4), which refer to the four experiments that were performed. The archives contain a folder structure, which should allow for compatible extractions, so that archives can be downloaded to a common local folder (e.g. using a script) and extracted there without running into file name conflicts. Several teams collaborated to come up with this dataset. Below we list the teams from which data was used and is part of the current version of the dataset. More data may be published in the future and added in a later version. The teams collaborated to varying degrees for different tasks.","accessed":{"date-parts":[[2022,4,16]]},"author":[{"family":"Sonder","given":"Ingo"},{"family":"Graettinger","given":"Alison H."},{"family":"Neilsen","given":"Tracianne B."},{"family":"Matoza","given":"Robin S."},{"family":"Taddeucci","given":"Jacopo"},{"family":"Oppenheimer","given":"Julie"},{"family":"Lev","given":"Einat"},{"family":"Tsunematsu","given":"Kae"},{"family":"Waite","given":"Gregory P."},{"family":"Valentine","given":"Greg A."},{"family":"Befus","given":"Kenneth"}],"citation-key":"sonder2018NSFLarge2021","DOI":"10.5281/ZENODO.5879934","issued":{"date-parts":[[2021,8,31]]},"language":"en","license":"Creative Commons Attribution 4.0 International, Open Access","publisher":"Zenodo","source":"DOI.org (Datacite)","title":"2018 NSF Large Scale Experiment Workshop on Volcanic Blasts","type":"dataset","URL":"https://zenodo.org/record/5879934","version":"0.5"}, 48 {"id":"sonderMeterScaleMagmaWaterInteraction2017","abstract":"These are video and other sensor data of experiments in which \"magma\" — that is: volcanic rock, re-melted at ca. 1300°C — interacts with liquid water. The experiments aim to better understand the escalation behavior of the processes involved when magma comes into contact with liquid water. The dataset will grow over time as data of new experiments is added. <strong>Changes</strong> Version 1.0: Add the <code>pr06</code> experiment. Version 0.11: Add the <code>pr05</code> experiment. Version 0.10: Add the <code>ir16</code> experiment. Version 0.9: Add the <code>ir15</code> experiment. Version 0.8: Add the <code>ir14</code> experiment. Version 0.7: Add the <code>ir13</code> experiment. Version 0.6: Add the <code>ir12</code> experiment. Version 0.5: Add the <code>ir07</code> experiment. Version 0.4: Add the <code>ir06</code> experiment. Version 0.3: Add the <code>ir05</code> experiment. Version 0.2: Add the <code>ir04</code> experiment. Version 0.1: Start with experiment <code>ir03</code>.","accessed":{"date-parts":[[2023,9,15]]},"author":[{"family":"Sonder","given":"Ingo"}],"citation-key":"sonderMeterScaleMagmaWaterInteraction2017","DOI":"10.5281/ZENODO.7331894","issued":{"date-parts":[[2017,10,5]]},"language":"en","license":"Creative Commons Attribution 4.0 International, Open Access","publisher":"Zenodo","source":"DOI.org (Datacite)","title":"Meter-Scale Magma-Water Interaction Experiments","type":"dataset","URL":"https://zenodo.org/record/7331894","version":"1.0"}, 49 {"id":"sonderVaporFilmLifetime2022","abstract":"<strong>Video records of the meta-stable vapor film conditions on a spherical magma sample in contact with water.</strong> The dataset is the base the following article:<br> <em>Experimental constraints on the stability and oscillation of water vapor film–a precursor for phreatomagmatic and explosive submarine eruptions. </em>By I. Sonder, and P. Moitra, 2022 in Frontiers in Earth Science, 10, doi: 10.3389/feart.2022.983112 . The dataset consists of observations (videos) of three experiments, and manually drawn polygons outlining the vapor film on the melt sample, or areas of direct magma-water contact. Video material is stored in two formats: (a) as video file (<code>.mp4</code>) and (b) as zip container that contains each of the video's frames in <code>.jpg</code> format. The polygon markup is stored in JSON format. <strong>Changes</strong> <strong><em>Version</em> 0.1:</strong><br> Initial upload of video and polygonal markup material.","accessed":{"date-parts":[[2023,9,15]]},"author":[{"family":"Sonder","given":"Ingo"},{"family":"Moitra","given":"Pranabendu"}],"citation-key":"sonderVaporFilmLifetime2022","DOI":"10.5281/ZENODO.6950484","issued":{"date-parts":[[2022,8,1]]},"language":"en","license":"Creative Commons Attribution 4.0 International, Open Access","publisher":"Zenodo","source":"DOI.org (Datacite)","title":"Vapor Film Lifetime at Magma-Water Interface","type":"dataset","URL":"https://zenodo.org/record/6950484","version":"0.1"}, 50 {"id":"whiteQuenchGranulationMagma2008","abstract":"When a magmatic melt encounters water, heat is transferred and in many cases the melt is fragmented to varying degrees by a range of processes. Explosive MFCI interactions result from extremely rapid heat transfer during fine fragmentation. Under other conditions, interactions extend from quiet steaming to non- explosive granulation. Among the many variables in natural environments inferred to play a role in determining the style of magma-water interaction is the presence of impurities, such as particulate sediment, in the water. This has been argued to be of particular significance for interactions within volcanic vents, where debris accumulates during the course of an eruption. A simple set of experiments was undertaken at the Physical Volcanology Lab in Wuerzburg, Germany, to investigate the effect of such particulate mixtures. Magma (~200 gm) was poured from a fixed height into a receptacle with pure water, and water with 10, 20, and 30 percent suspended mud. Thermocouple and force measurements were collected during and after each pour, and reveal that with increasing sediment concentrations, the rate of heat transfer from magma to coolant, and the intensity of thermal granulation, is progressively reduced. The scale of reduction is impressive; for water, virtually all heat transfer from magma to water is complete within a few seconds after the pour, whereas with 30 percent suspended clay this stretches to in excess of 10 minutes. The change reflects reduced fragmentation of the magma, reduced heat capacity of the coolant, and strongly reduced convection in the coolant. A separate pour into a liquefied sand-clay sediment (64 percent sediment by mass) produced similarly reduced heat transfer, but was accompanied by quiet but pervasive hydrodynamic fragmentation of the melt into centimetric glass spheres, many of which welded together within the sediment.","author":[{"family":"White","given":"J. D. L."},{"family":"Zimanowski","given":"Bernd"},{"family":"Büttner","given":"Ralf"},{"family":"Sonder","given":"Ingo"}],"citation-key":"whiteQuenchGranulationMagma2008","event-title":"2008 AGU Fall Meeting","issued":{"date-parts":[[2008,12]]},"page":"V22C-08","publisher":"American Geophysical Union","title":"Quench and granulation of magma in sediment-water mixtures: 1st experimental results","type":"paper-conference","volume":"2008"} 51 ]