Experiments with vertically and laterally migrating subsurface explosions with applications to the geology of phreatomagmatic and hydrothermal explosion craters and diatremes

Valentine, Greg A.; Graettinger, Alison; Macorps, É.; Ross, Pierre-Simon; White, James D. L.; Döhring, Erika; Sonder, Ingo

doi:10.1007/s00445-015-0901-7

Cited by 70 publications

(47 citation statements)

References 36 publications

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“…Recent field and experimental studies of maars and their underlying diatremes show that subsurface explosions may or may not erupt onto the surface, depending upon their depths and energies; shallow explosions (upper ∼200 m) are most likely to actually eject material, while deeper blasts brecciate magma and country rock and mix them through combined upward-directed debris jets and subsidence (e.g., White and Ross, 2011;Graettinger et al, 2014;Valentine et al, 2015). A tephra ring produced by this end-member type of activity will have many depositional units, corresponding to many explosions, and will be dominated by tuff breccias, stratified and cross-stratified lapilli-tuff beds produced by pyroclastic surges, ballistic bombs and blocks, and thin ash fallout beds.…”

Section: Characteristics Of the End-membersmentioning

confidence: 99%

Maars to calderas: end-members on a spectrum of explosive volcanic depressions

et al. 2015

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We discuss maar-diatremes and calderas as end-members on a spectrum of negative volcanic landforms (depressions) produced by explosive eruptions (note-we focus on calderas formed during explosive eruptions, recognizing that some caldera types are not related to such activity). The former are dominated by ejection of material during numerous discrete phreatomagmatic explosions, brecciation, and subsidence of diatreme fill, while the latter are dominated by subsidence over a partly evacuated magma chamber during sustained, magmatic volatile-driven discharge. Many examples share characteristics of both, including landforms that are identified as maars but preserve deposits from non-phreatomagmatic explosive activity, and ambiguous structures that appear to be coalesced maars but that also produced sustained explosive eruptions with likely magma reservoir subsidence. A convergence of research directions on issues related to magma-water interaction and shallow reservoir mechanics is an important avenue toward developing a unified picture of the maar-diatreme-caldera spectrum.

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Section: Characteristics Of the End-membersmentioning

confidence: 99%

Maars to calderas: end-members on a spectrum of explosive volcanic depressions

et al. 2015

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“…Ennek hatására egyre kisebb lett a litoklasztok mennyisége a kitörés előre -haladtával, jelezvén a kürtő egyre stabilabb állapotát (LORENZ 1973(LORENZ , 1986. Jellegzetes, juvenilis szemcsékben gazdagabb zónák több diatréma esetében is ismertek, melyek jó analógiát mutathatnak a Badacsony megőrzött vulkáni szerkezetének értelmezéséhez (bár ilyen zónák a feltártsági viszonyok miatt a Badacsonynál nem ismertek; VALENTINE & WHITE 2012, VALENTINE et al 2015. 50% körüli juvenilis részarányt számos fiatal maart körülvevő piroklasztitgyűrűben is dokumentáltak, ami arra utal, hogy bizonyos periódusokban a vulkáni működést alapvetően a magmában oldott illók kiválása által okozott magmás típusú robbanásos kitörések jellemezhették (TCHAMABE et al 2015).…”

Section: Az Eredmények éRtelmezéseunclassified

A Badacsony freatomagmás piroklasztit-sorozata: következtetések a monogenetikus bazaltvulkáni működés folyamataira és formáira

et al. 2017

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In this paper the first quantitative description and volcanological interpretation is given of the Badacsony Hill, the latter being the most well-known butte of the Bakony-Balaton Highland Volcanic Field (BBHVF). The pyroclast/lithics ratio of the pyroclastics was investigated by using point-counting image analysis methodology on the surfaces of handcut specimens. The isometrical shape of different grains allowed the obtained 2D data to be converted to 3D volume data. By using this methodology it was possible to infer the relative depth of explosions with respect to the synvolcanic surface and the syneruptive morphology; moreover, the effusive and explosive phases of the volcanism could be identified.The results of point-counting image analysis and the position and extent of the phreatomagmatic sequence on the Badacsony Hill imply that the Badacsony volcano was a monogenetic (probably polycyclic) tuff ring or shallow maar volcano. Such volcanism is associated with the interaction of hot, molten material with groundwater, and this triggers shallow explosions. The low amount of accidental lithics within the deposits confirms the tuff ring scenario; however, such a low amount of accidental lithics could also be observed within deposits from shallow maars when these were formed on a soft, unconsolidated basement. Such an alternative model is envisaged for Badacsony.The development of the volcanism can be divided into explosive and effusive phases, based on the different composition and on the relative stratigraphic position of the respective phreatomagmatic sequences. Based on these results the present study proposes a volcanic evolution model. Given the scarcity of volcanological data on the Badacsony Hill, the results presented here could give a basis for further regional volcanological investigations.Keywords: Badacsony, Bakony-Balaton Highland Volcanic Field, image analysis, maar, monogenetic, phreatomagmatic eruption, tuff ring Összefoglalás A tanulmányban a Bakony-Balaton-felvidéki vulkáni terület (BBVT) legismertebb tanúhegyén, a Badacsonyon kibukkanó freatomagmás piroklasztit-összlet első kvantitatív leírását és vulkanológiai értelmezését mutatjuk be. A piroklasztitok juvenilis/litikus törmelékeinek arányát pontszámlálásos módszerrel vizsgáltuk vágott kézipéldány-fel színe -ken. A felület%-ban kapott eredményeket a kőzetminták teljes térfogatára vonatkozónak vettük. E módszer segít ségével meghatároztuk a freatomagmás robbanások relatív mélységét a szinvulkáni felszínhez képest, következ tetéseket vontunk le a lehetséges szineruptív vulkánmorfológiára, valamint a terepi megfigyelések és korábbi tanulmányok alapján rekonst ruáltuk a vulkán működésének teljes fejlődéstörténetét.A képelemzés során megállapítottuk a litikus elegyrészek minimális arányát. Ebből, valamint a piroklasztitok térbeli elter jedéséből és rétegtani helyzetéből valószínűsíthető, hogy a Badacsony egy monogenetikus (esetleg policiklikus) tufagyűrű vagy sekély maar vulkán volt, amelynek kialakulásában a víz-magma kölcsönhatás követke...

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“…The experiments consisted of shallow-buried explosions (blasts) into layered granular media (pads), in order to mimic the effects of discrete explosions, resulting in the formation of a crater and its subsurface structure. The reader is referred to Ross et al (2013), Graettinger et al (2014), and Valentine et al ( , 2015, for a detailed description of the experiments, and for information on energetics of phreatomagmatic explosions in forming maar-diatremes. The blasts were performed using chemical explosives of known size and energy density, emplaced at defined scaled depths (scaled…”

Section: Experiments Setupsmentioning

confidence: 99%

The effects of the host-substrate properties on maar-diatreme volcanoes: experimental evidence

et al. 2016

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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 subsurface 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 subsurface 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 nonlinear for crater depth, and nonexistent 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.

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Experiments with vertically and laterally migrating subsurface explosions with applications to the geology of phreatomagmatic and hydrothermal explosion craters and diatremes

Cited by 70 publications

References 36 publications

Maars to calderas: end-members on a spectrum of explosive volcanic depressions

Maars to calderas: end-members on a spectrum of explosive volcanic depressions

A Badacsony freatomagmás piroklasztit-sorozata: következtetések a monogenetikus bazaltvulkáni működés folyamataira és formáira

The effects of the host-substrate properties on maar-diatreme volcanoes: experimental evidence

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