To understand the complex structure of magmatic plumbing systems beneath volcanoes, one needs to study the different textures shown in the igneous rocks produced by the volcano in question. By doing this, one can get a clue of the processes that resulted in the final rock. One of the most important methods to use for studying rock samples is the Crystal Size Distribution (CSD), which can reveal a great amount of information about the history of the rock and give an insight in the journey of the crystals during their time in the magma. An extinct volcano named Chachahuén, located in Argentina, South America, was chosen for this study. Samples of rock were collected from one of its laccoliths named Cerro Bayo and was identified as hornblende-bearing dacite. The difference in crystal size was very significant in these samples, with both larger and smaller crystals embedded in the same matrix. This is interesting considering the fact that large crystals form by slow cooling of the magma while smaller crystals form as the magma cools rapidly. By studying the CSD and interpreting other textures found in samples of igneous rock, one may interpret different processes which affected the crystals, indicating what the structure of the magma chamber once looked like. / För att kunna förstå den komplexa strukturen hos magmatiska system under vulkaner måste man studera olika texturer som påträffas i de magmatiska bergarter producerade av vulkanen i fråga. Genom att göra detta kan man få en inblick i de processer som resulterade i den slutgiltiga bergarten. En av de viktigaste metoderna att använda sig av för att studera stenprov är kristallstorleksfördelningen (CSD), som kan avslöja en mängd viktig information om bergarten och kristallernas historia under sin färd i magman. En slocknad vulkan vid namn Chachahuén belägen i Argentina, Sydamerika, valdes ut för denna studie. Stenprover samlades från en av dess lakkoliter med namnet Cerro Bayo, och identifierades som hornblände-bärande dacit. Skillnaden i kristallstorleken var mycket markant, med både större och mindre kristaller inbäddade i samma matrix. Detta är intressant med tanke på att stora kristaller bildas under en långsam nedkylning av magma medan mindre kristaller bildas när magma kyls ner snabbt. Genom att studera CSD och tolka andra texturer som finns hos magmatiska stenprover kan man tolka olika processer som har påverkat kristallerna, vilket i sin tur indikerar hur strukturen av magmakammaren en gång såg ut.

Too few documentative descriptions exist from the reactivated Proterozoic Nasa Basement window in Sweden. This re-exposed crustal piece predominantly consisting of 1.8 Ga granite and volcanic basement rock lack structural evidences on maps. The Western Gneiss region gave example of how rocks in extreme cases may experience protolith overprinting through collisional vertical granite basement subduction to eclogite ambient conditions, which would give traces in metamorphic quartz (coesite), muscovite, pyroxene and kyanite, and increased densities. Preliminary indications from literature points towards a locally passive Nasa Basement with limited translation, but because of too little documentation it cannot be assured metamorphic inertia under fluid absence has been unimportant in the basement evolution. To address this highly structural issue, field reconnaissance mapping and sampling was carried out, and aimed to achieve a structural characterisation of historic deformation back to Proterozoic time. Observations were collected from 166 outcrop vicinities, and 17 of 27 carefully examined thin sections aimed to describe microscopic structures, in addition to mineral relation to metamorphic minerals. Collected evidences in this project encompass a Proterozoic macroscopic concentric fold with axis striking NW-SE, as well as, mesoscopic folds striking WNW-ESE. Tectonic movements record syn-collisional top-SE and post- collisional top-SW translation, which truncate weakly shortened and foliated blocks. Basement blocks locally preserve igneous coarse but weakly recrystallized texture fabrics. Overall optically produced paleothermometry indicates low- to medium grade facies conditions of deformation, through widespread bulging recrystallization, occasional subgrain rotation and rare grain boundary migration in quartz. Feldspar response to deformation is brittle and rarely ductile. Hydrous biotite, chlorite and epidote are abundant. Mineralogy together with an observed average density of 2,6 g/cm3 can possibly reject the idea of unreacted local continental subduction to eclogite depths, due to the overall presence of hydrous mineral phases. Top-to-the shear sense proves Caledonian reactivation, but Bourguer anomaly indicates at least locally an important limited translation. NW-SE striking lineaments and strikes of foliation show best accordance with lineaments mapped in Norway and alignment with tectonic contacts in the Baltica interior, and do so show the best examples of candidates for Proterozoic structures.

Sub-volcanic intrusions can form an extensive network of sills, dikes and other intrusion types that make up a plumbing system beneath volcanoes. Such intrusions are the heat source for high-temperature geothermal systems in volcanic areas and therefore, it is of great importance to study them in relation to geothermal exploration and production. In this thesis a part of the plumbing system of Breiðuvík caldera, an eroded central volcano in northeastern Iceland, is studied. A set of magmatic intrusions showing a great range in size and shapes, is exposed in Leirfjall, a mountain composed of the eroded caldera infill of the Breiðuvík volcanic system. Data from these intrusions and their host rock is used as the foundation for numerical modeling using finite element method (FEM) constructed in this thesis. The numerical modeling assumes heat transfer in porous media including conduction and convection where fluid flow is governed by the Darcy‘s law. The aims of it is to compare the cooling times of different intrusions and the temperature distribution caused by intrusions of different sizes and shapes. To obtain input parameters for the numerical modeling, a thermometry study based on the mineral chemistry of the magmatic intrusions in Leirfjall is conducted and the thermal and physical properties of the sedimentary host rock are estimated, while literature values are used for basaltic lava and hyaloclastite host rocks for comparison. The results of the numerical modeling suggest that higher maximum values of increased temperature are reached above one thick intrusions compared to multiple thinner intrusions. When comparing dikes and sills, the dikes raise the maximum temperature of the host rock more than the sills, while the sills raise the average temperature above the intrusions more than dikes. Results of the estimated heat transfer from an arrangement of intrusions similar to what is observed in Leirfjall suggests that a significant increase in maximum increased temperature caused by the intrusions would be short-lived, while the average increase would still be constant over a longer time. Despite of the simplified structure of the numerical models it is the hope that they will provide inspiring data for further research and contribute to a better understanding of the relationship between the shallow magmatic intrusions and geothermal systems. / Vulkaner är en viktig energikälla i många länder runt om i världen. Geotermisk vätska och ånga av högtemperatur som finns i vulkanområden kan utnyttjas för bland annat elproduktion och fjärrvärme. Värmekällan till de geotermiska områdena är magma som ligger ytligt i jordskorpan. All magma når inte ytan i utbrott, utan stannar under vulkanen i form av magmaintrusioner. Intrusionerna av olika former och storlekar utgör ett nätverk som tillsammans utgör vulkanens magma transportsystem. I denna studie studeras en uppsättning av magmaintrusioner på nordöstra Island. Intrusionerna har en gång befunnit sig längre ner i jordskorpan under ett aktivt vulkanområde men exponeras nu vid ytan på grund av glacial erosion. Intrusionernas storlek och form varierar, men de flesta återfinns som gångar, både vertikala och horisontella. När en magmatintrusion bildas värms omkringliggande berggrund och grundvatten upp. Studiens fokus är att undersöka hur temperaturfördelningen i omgivningen skiljer sig vid en stor intrusion jämfört med flera mindre intrusioner med totalt samma volym. Även effekten från olika typer av berggrund runt intrusionerna studerades genom att jämföra temperaturfördelningen och kylningstiderna för intrusioner i tre vanliga bergarter. Numerisk modellering användades för att besvara dessa frågor. Bergarternas fysiska och termiska egenskaper krävdes som ingångsparametrar för den numeriska modelleringen. Parametrana uppskattades genom laboratorieexperiment och termometriberäkningar från fältprover. Värden från publicerat material användes också i modelleringen. Resultaten från den numeriska modelleringen antyder att högre maximivärden för temperaturen nås i berget över en stor, enskild intrusion jämfört med flera mindre intrusioner. När man jämför vertikala og horisontella gångar, ökar de vertikala gångarna berggrundens temperatur mer än de horisontella, medan medeltemperaturen ökar mer över horisontella gångar än i vertikala gångar. Trots den numeriska modellens förenklade struktur är förhoppningen att den nya datan kan inspirera vidare forskning, och bidra till en bättre förståelse om förhållandet mellan grunda magmaintrusioner och geotermiska system.

The Kiirunavaara mine hosts one of the world’s largest apatite-iron ore mineralisations. This ore body has been subject to large amounts of research as well as extensive mining. The ore body is situated between the syenitic foot wall and the rhyodacitic hanging wall, of which consists of differing mineralogy and characteristics. Both these rock masses contain intrusive porphyry dykes, with distinct characteristics of it own. The aim of this study was to analyse 31 samples, mainly in the form of thin sections, and determine the mineralogy and identify eventual microstructures. This was done through the use of optical mineralogy as well as EDS/WDS analysis at the National Microprobe Lab at Uppsala University. The foot wall consists of syenite-porphyry and is dominated by feldspar in both groundmass as well as phenocrysts. Characteristic for the syenite-porphyry is the rounded nodules containing actinolite, titanite, magnetite and chlorite. The hanging wall is defined as quartz-bearing porphyry. It is a rhyodacitic rock with large amounts of feldspar along with green silicates, quartz, titanite and calcite. The intrusive porphyry dyke-rocks share many similarities with the quartz-bearing porphyry, but contain a finer groundmass with larger amounts of clinopyroxene, as well as lower amounts of quartz, magnetite and titanite. Hydrothermal alteration is prevalent in all the types of rock. Alteration minerals such as actinolite, biotite and chlorite are very common within the Kiirunavaara-rocks. The quartz-bearing porphyry displays the most extensive exposure to hydrothermal fluids. The hydrothermal fluids have penetrated several samples, replacing minerals and leaving very few remnant, older minerals. The quartz-bearing porphyry contains the most prominent deformation structures, of varying extent and magnitude. Magmatic flow structures can be seen in the groundmass, as parallel alignment of feldspar and silicate grains. Evidence of solid-state deformation most commonly occurs as pressure shadows around feldspar phenocrysts. / Kiirunavaara-gruvan är belägen vid en av världens största mineraliseringar av apatit-järnmalm. Denna malmkropp har stått i fokus för både omfattande gruvdrift samt genomgripande forskning. Malmkroppen är belägen mellan den syenitiska liggväggen och den ryodacitiska hängväggen, som består av varierande mineralogi och karaktär. Båda av dessa bergmassor innehåller intrusiv gångporfyr med distinkt karaktär. Målet med denna studie var att analysera 31 prover, främst i form av tunnsliper, och bestämma dess mineralogi samt att identifiera eventuella mikrostrukturer. Detta genomfördes genom användning av optisk mineralogi och EDS/WDS-analys vid det nationella mikrosondslaboratioriet vid Uppsala Universitet. Liggväggen består av syenitporfyr och domineras av fältspat i både mellanmassa och som fenokrister. Karaktäristiskt för syenitporfyren är de rundade nodulerna, innehållandes aktinolit, titanit, magnetit och klorit. Hängväggen definieras som kvartsförande porfyr. Det är en ryodacitisk bergart med stora mängder fältspat, gröna silikater, kvarts, titanit och kalcit. Gångporfyren delar många likheter med den kvartsförande porfyren, men består av en finare mellanmassa med större mängd klinopyroxen, samt innehåller mindre mängder kvarts, magnetit och titanit. Hydrotermal omvandling är allmänt förekommande i alla bergarter i Kiirunavaara. Omvandlingsmineral så som aktinolit, biotit och klorit är väldigt vanliga hos Kiirunavaara-bergarterna. Den kvartsförande porfyren uppvisar den mest omfattande exponeringen av hydrotermala vätskor. De hydrotermala vätskorna har penetrerat ett antal prover och därigenom omvandlat mineral, med liten mängd äldre mineral kvar. Den kvartsförande porfyren innehåller de mest prominenta deformationsstrukturer, av olika omfattning och magnitud. Magmatiska flytstrukturer kan observeras i mellanmassan som parallell orientering av fältspat- och silikatkorn. Tecken av fastfasdeformation förekommer främst i form av tryckskuggor runt fältspatsfenokrister.

Kongsfjordhallet is situated at 79° N on the North coast of Kongsfjorden, Spitsbergen.The landscape shows a large diversity of landforms and sediments and the aim of thisstudy has been to investigate the spatial distribution and temporal differences betweenthese landforms.The most prominent landform is interpreted as a lateral moraine dividing the area fromsoutheast to northwest. This is probably a sign of a standstill during the deglaciation ofan ice-sheet glacier tongue filling the fjord. The valley-glaciers at Kongsfjordhallet haveadvanced after this event and left end moraines on top of the lateral moraine. Largeamounts of meltwater have eroded parts of the Kongsfjordhallet, creating several fossilmeltwater channels that dissect the landscape. Erratic boulders of mainly gneiss type arescattered all over the landscape, as high up as 500 m a.s.l. In addition to the erraticboulders, a lot of allochthonous material is found incorporated in local material,especially as a diamict interpreted as till that covers large parts of Kongsfjordhallet.The till can likely be correlated to one of the diamict units in the cliff sections at theKongsfjordhallet coast. At present, two large ravines drain the area, moving water fromthe glaciers to the ocean and a beach is developing in the Southeast part of the area dueto ocean transgression. Landforms from two glacial events are found, one regional andone local. An episode of high sea-level as well as fluvial and mass-wasting activity afterthe deglaciation is also recorded. The formation of the landforms in the area is believedto be after the Last Glacial Maximum and into the Holocene, but no absolute dates areavailable. / SciencePub

Aligned ikaite porphyroblasts have been replaced by calcite with a maximum volume decrease of ~88% in Neoproterozoic Dalradian metalimestone exposed near Ballygrant on Islay, Scotland. Microscopic and structural analyses reveal that the ikaite minerals formed before deformation, at a time when Scotland was located at the lower latitudes, thus indicating a cold climate at the time of formation. The Ballygrant metalimestone underlies a ~900 meter thick glacial deposit that has previously been linked to the ‘Snowball Earth’ hypothesis. The discovery of these ikaite pseudomorphs below the glacial deposit points toward a relatively slow cooling of the climate near the equator reflecting a transition toward a ‘normal’ glacial period and thus refutes a suggested ‘Snowball Earth’ event, which is reported to reflect a more abrupt switch over from warm to cold climate in the sediment record.

Geophysical methods are frequently applied in conjunction with exploration efforts to increase the understanding of the surveyed area. Their purpose is to determine the nature of the geophysical response of the subsurface, which can reveal the lithological and structural character. By combining geophysical measurements with the drill core data, greater clarity can be achieved about the structures and lithology of the borehole. The purpose of the project was to give the student an opportunity to discover borehole logging operations and to have a greater understanding of the local geology, in particular the iron mineralizations in the apatite iron ore intersected by the boreholes. In order to do this, the student participated in performing a geophysical borehole survey and analyzing the results. These were combined with a drill core log in order to cross plot the results and increase understanding. / Geofysiska metoder används ofta i samband med prospektering för att öka förståelsen av området. Utförda från ytan ger de en relativt god tolkning av vad som kan finnas på djupet och är även kostnadseffektiva jämfört med provborrning. Borrhålsloggning sker däremot efter att själva hålet borrats och ändamålet är ofta att utöka förståelsen om området omedelbart kring det loggade hålet. Genom att kombinera geofysisk fältdata med tolkning av borrkärnan kan man erhålla en ökad förståelse för borrhålets strukturer och litologi. Syftet med det här projektet var att utöka studentens förståelse inom borrhålsloggning, samt att avgöra hur relevant metoden är för att identifiera järnmineraliseringar i apatitjärnmalmen som kännetecknar norra Bergslagen

The southern part of Iceland incorporates two parallel volcanic zones, the Eastern Volcanic Zone and the Western Volcanic Zone. These two branches are connected by an E-W transform. Hekla is located close to intersection between the two plate boundaries. Hekla is one of Iceland's most active and explosive volcanoes. Unique to Hekla is that it is one of the few volcanoes on Iceland that produces explosive silica rich magma. Hekla gives no clear warning of its eruptions and sends out seismic signals with very short notice. It is therefore of interest to try to understand Hekla's magma system and magmatic processes in order to gain an increased knowledge of its volcanic processes. The study is based on calculating crystallization conditions for the minerals plagioclase, clinopyroxene and orthoproxene. Calculations is based on the assumption that minerals, which are in equilibrium with the associated melt are directly associated with the thermodynamics of crystallization. The result of the study shows that Hekla's magma chamber is located at a depth of 8-12 km. The samples from Hekla are poor in minerals, which can be explained by separation due to fractional crystallization that forms a crystal mush. Fast ascending primitive magma along with degassing will eventually lead to an eruption. The absence of crystal zoning indicates a limited chance of magma mixing or crustal contamination. Oxides related to the eruption tend to comprise a low titanium content, which is related with an increased pressure condition. Geospeedometry suggested that recharge occurred up to 10 days before eruption. Erupted oxides shows up to 30 years residence which suggest long-term crystal mush. / Hekla är en av Islands mest aktiva och explosiva vulkan. Dess vulkaniska beteende grundar sig i det underliggande magma systemet samt kompositionen av magman. Unikt för Hekla är att det är en av få vulkaner på Island som producerar explosiv kiselrik magma. Hekla sänder dessutom inte ut tydliga varnings signaler innan utbrott. Det är därför av intresse att försöka förstå Heklas magma system och magmatiska processer för att kunna få en ökad uppfattning om dess vulkaniska processer.Undersökningen grundar sig i att beräkna kristalliseringsförhållanden för mineralerna plagioklas, klinopyroxen samt ortopyroxen. Resultatet av studien påvisar att Heklas magmaförvar är belägget på ett djup av 8-12 km. Proverna från Hekla har varit fattiga i mineraler vilket kan förklaras genom att mineraler har separerats från magman genom kristallisering. Magmas komposition kommer därför att ändras i och med att mineraler som kristalliserats tar bort element från den. Mineralkristallerna bildar sedan en egen zon som innefattar en liten del magma. Utbrotten triggas sedan när varm mafisk magma från ett större djup infiltrerar den grunda magma kammaren samt frisläppandet av gaser som sker vid kristallisering av mineraler.Beräkningar av tiden det tar för oxider att svalna tyder på att ny magma har infiltrerat magma kammaren upp till 10 dagar innan utbrottet. Den nya magman hinner inte blanda sig med den mer utvecklade magman. Detta event skulle leda till att kluster av mineral skulle följa med i utbrottssekvensen. Ett antal oxider visar även på att det börjat svalna upp till 30 år sedan, vilket kan förklaras av en zon bestående av kristaller.

Fluids, mainly H2O and CO2, are released from H- and C-bearing phases during prograde metamorphism. Because of the buoyancy of these fluids, they rise within the crust towards the surface of the Earth. Metamorphic fluids take advantage of permeable horizons, shear zones, fold hinges, fractures, and are channelled into high-flux zones. Fluid fluxes for channelized fluid flow may exceed background pervasive fluxes by several orders of magnitude. Metamorphic fluids react with the surrounding rock during fluid flow, and altered zones are commonly observed adjacent to high-flux conduits. Fluid-altered rock is texturally, mineralogically, chemically, and isotopically different from rock unaffected by fluid flow. In this thesis, fluid-rock interaction is studied at two localities in the Scottish Highlands: Glen Esk and the Isle of Islay. Glen Esk is one of the type localities used by George Barrow (1853-1932) to propose the concept of metamorphic zones and metamorphic index minerals as an approximate determination of metamorphic grade. In several of the metamorphic zones in Glen Esk, index mineral distribution is highly dependent on proximity to veins. The occurrence of index minerals is therefore not only controlled by pressure and temperature, but also by the availability of metamorphic fluids. Evidence of a retrograde fluid flow event from the North Esk Fault is observed in Glen Esk, for which a time-averaged fluid flux of 0.0003 – 0.0126 m3∙m-2∙yr-1 is calculated. The duration of the fluid event is estimated to between 16 and 334 kyr. On the Isle of Islay, kyanite is observed in rocks of chlorite or lower-biotite metamorphic grade, i.e. much lower temperatures than usually associated with kyanite formation. The favoured explanation for this is retrograde infiltration of extremely high-CO2 fluids, at least locally XCO2 &gt; 0.7, at ~340°C, which altered these rocks and stabilised kyanite in a carbonate-bearing assemblage. Oxygen and carbon stable isotope profiles across the Islay Anticline reveals highly channelized fluid flow along the axial region of this fold, with fluid:rock ratios at least four times higher than in rock farther away from the fold. Although carbon and oxygen isotope ratios of metacarbonate rocks were altered along the Islay Anticline, negative anomalies observed below and above the Port Askaig Tillite Formation cannot solely be attributed to metamorphic fluid flow, which implies that these rocks to varying degree retain their primary paleoclimatological isotopic signatures. / Stora volymer H2O och CO2 frigörs som fluider under prograd metamorfos. Metamorfa fluider har lägre densitet än det omgivande berget, varför de stiger genom jordskorpan mot jordytan. Metamorfa fluider kanaliseras i permabla lager, skjuvzoner, veckaxlar, sprickor och andra högflödeszoner. Kanaliserade fluidflöden kan vara flera storleksordningar högre än bakgrundsvärdet för fluidflöde inom en bergart. Metamorfa fluider reagerar under transport med det omgivande berget och bildar fluidomvandlade zoner i anslutning till högflödeskanaler. Fluidomvandlat berg uppvisar texturella, mineralogiska, kemiska och isotopsammansättningsmässiga skillnader i jämförelse med berg som inte utsatts för fluidomvandling. I denna avhandling behandlas reaktioner mellan fluid och berg som studerats i två lokaler i de skotska högländerna: Glen Esk och Islay. Glen Esk är en av de typlokaler som George Barrow (1853-1932) använde för att lägga fram konceptet om metamorfa zoner och metamorfa indexmineral som används för att ungefärligt uppskatta metamorf grad. I flera av de metamorfa zonerna är förekomsten av indexmineral i hög grad beroende av närhet till kvartsådror, vilket visar att bildandet av indexmineral inte bara styrs av tryck och temperatur, utan också av åtkomst till metamorfa fluider. I Glen Esk finns också spår av ett fluidflöde från North Esk-förkastningen, under retrograda metamorfa förhållanden, för vilket mededfluidflödet över tid uppgår till 0.0003 – 0.0126 m3∙m-2∙år-1. Denna fluidflödeshändelse beräknas ha pågått mellan 16 000 och 334 000 år. På ön Islay i de sydvästra högländerna återfinns bergarter, som trots sin låga metamorfa grad i klorit- eller biotitzonen innehåller mineralet kyanit, dvs. temperaturer långt under vad som vanligen associeras med kyanitbildning. Detta förklaras med infiltration av fluider med extremt hög CO2-halt, åtminstone lokalt så högt som XCO2 &gt; 0.7, vid ca. 340°C. Fluidomvandling av dessa bergarter stabiliserade kyanit tillsammans med karbonatmineral. Syre- och kolisotopprofiler över Islayantiklinen påvisar hög kanalisering av fluider längs dess veckaxeln. Förhållandet mellan fluid och berg var mer än fyra gånger så högt i närheten av veckaxeln jämfört lokaler längre ifrån densamma. Påverkan av metakarbonatbergarters isotopförhållanden har skett längs Islayantiklinen, men fluidpåverkan kan inte ensamt förklara de isotopanomalier som observerats under och ovan Port Askaig-tilliten, varför dessa bergarter kan ha bibehållit sin primära paleoklimatologiska isotopsignatur. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript.</p>

Magma plumbing systems represent the physical framework of magma transport and storage from the source region in the mantle, through the crust, until reaching the surface in a volcanic eruption. Characterising the different aspects of magma plumbing, in particular the distribution of magma storage zones throughout the crust, is of key importance to better understand the behaviour of individual volcanoes. In particular, shallow crustal magma storage and associated magma-crust interaction processes could potentially explain some of the worlds most unpredictable and explosive volcanoes. This thesis studies magma plumbing architecture in the Sunda Arc (Indonesia), and the North Atlantic Igneous Province, based on elemental and isotope geochemistry, and derived petrological modelling. In this study, I have employed petrological models, so called geothermobarometers, to calculate pressures and temperatures (P-T) of crustal magma storage. Geothermobarometers are calibrated thermodynamic formulations based on the composition of magmatic minerals and their co-existing melt as a function of the P-T conditions of crystallisation. Using the calculated P-T estimates, I was able to derive the depth of magma storage, and thereby reconstruct the architecture of magma storage systems. A number of different geothermobarometers based on different mineral phases, including plagioclase, clinopyroxene and olivine, were used for this purpose, The geothermobarometric modelling was combined with additional elemental and isotope geochemical analyses, as well as collaborations with geophysical investigations. These additional approaches were used to corroborate the findings of the geothermobarometric modelling, and also to model and quantify magma-crust interaction processes that take place during crustal magma storage, such as assimilation of crustal lithologies into the magmatic system. The findings of this thesis build upon the growing body of evidence in support of the prevalence of shallow magma storage in different volcanic settings worldwide. This realisation is relevant to volcano monitoring and hazard mitigation worldwide.