Articles de revues sur le sujet « Experimental volcanology »

Abstract. Fluid flow on different scales is of interest for several Earth science disciplines like petrophysics, hydrogeology and volcanology. To parameterize fluid flow in large-scale numerical simulations (e.g. groundwater and volcanic systems), flow properties on the microscale need to be considered. For this purpose experimental and numerical investigations of flow through porous media over a wide range of porosities are necessary. In the present study we sinter glass bead media with various porosities and measure the permeability experimentally. The microstructure, namely effective porosity and effective specific surface, is investigated using image processing. We determine flow properties like tortuosity and permeability using numerical simulations. We test different parameterizations for isotropic low-porosity media on their potential to predict permeability by comparing their estimations to computed and experimentally measured values.

The purpose of this paper is to integrate, or even modify where necessary, the geo-volcanological setting outlined by other authors on the history of the small volcanic field of San Venanzo (Umbria, Central Italy). To attain this goal, new accurate field investigations were carried out in that area, coupled with detailed stratigraphic studies and laboratory analyses, to support field evidence with experimental results. The first objective was to stress the importance of a groundwater reservoir whose interaction with magma at various degrees was responsible not only for the explosive character of volcanism in that area, but also for the complex morphology of the volcanic deposits that are widely scattered on the underlying sedimentary basement. Another objective was to clarify the role played by tectonic activity in enhancing the fast and discontinuous ascent of batches of magma from the mantle to the surface, through two different sets of faults, opened by tectonic unrest into the crust, that were also responsible for the morphology and spatial distribution of volcanic centres. This was considered to be very important in consideration of the still-active stress field of the region. Finally, special attention was focused on the presence of a palaeosol between two eruptive sequences, as it most likely denoted a split in the volcanic activity of this site into two separate phases. This observation leads to the conclusion that, in spite of its eruptive characteristics, the small volcano of San Venanzo is not monogenic. For all of these topics, a number of conclusions have been drawn and they are reported with more data in the following sections of this paper.

Olivine, once overlooked as a host of trace elements, is becoming increasingly important for our understanding of the kinetic and equilibrium behaviour of these elements. Much of our understanding of trace element substitution and diffusion in geological materials comes as a result of experimental and petrological studies of olivine. Here, we consider trace element concentrations and incorporation mechanisms, and how these relate to diffusive behaviour. If we understand trace element behaviour in olivine, we have a powerful tool kit that can be directly applied to address many problems in petrology and volcanology. Perhaps more importantly, what we have learned from olivine can be applied to other minerals and aid us in addressing other far-reaching questions from across the Earth sciences.

The turbulent motion of buoyant plumes released into turbulently convecting environments is studied. By assuming that the turbulent environment removes fluid from the plume at a rate proportional to a characteristic environmental velocity scale, we derive a model describing the fluid behaviour. For the example of pure buoyancy plumes, entrainment dominates near the source and the plume radius increases with distance, while further from the source removal, or extrainment, of plume material dominates, and the plume radius decreases to zero. Theoretical predictions are consistent with laboratory experiments, a major feature of which is the natural variability of the convection. We extend the study to include the evolution of a finite confined environment, the end-member regimes of which are a well-mixed environment at all times (high convective velocities), and a ‘filling-box’ model similar to that of Baines & Turner (1969) (low convective velocities). These regimes, and the motion of the interface in a ‘filling-box’ experiment, match experimental observations. We find that the convecting filling box is not stable indefinitely, but that the density stratification will eventually be overcome by thermal convection. The model presented here has important applications in volcanology, ventilation studies and environmental science.

Few furniture designs are built around the concept of withstanding earthquakes. This capstone project aims to integrate tensegrity into furniture to replicate the earthquake safety measures used on larger scales with seismic isolation and withstand earthquakes better than traditional furniture. The researchers tested the product at the Philippine Institute of Volcanology and Seismology (PHIVOLCS), located at Diliman, Quezon City. The researchers made use of the institute’s earthquake simulator to have the earthquake intensities scaled accurately. They made use of true experimental research design, which gave them access to the scientific method in making the designs for the furniture. The researchers conducted the experiment in four phases, denoted as the research phase, the design phase, the experiment phase, and the evaluation phase. The results showed that the calculated t-value of 35.317 is greater than the critical t-value of 2.56. This meant that tensegrity-integrated furniture is significantly more earthquake-resistant than traditional household furniture. Measures such as adding weights to the structure’s base increase further increase its stability. Tensile integrity integrated into furniture is a modern take on earthquake safety measures, similar to existing ones like seismic isolation. And with the proper setup and more improvements, its earthquake resistance factor can save lives.

Tanah longsor merupakan bencana tahunan yang senantiasa melanda disebagian wilayah Indonesia. Terjadinya bencana tanah longsor dapat menimbulkan dampak yang sangat besar baik terhadap kehidupan maupun lingkungan. Berdasarkan data Pusat Vulkanologi dan Mitigasi Bencana Geologi terdapat 918 lokasi rawan tanah longsor yang tersebar diberbagai wilayah di Indonesia. Provinsi Bali merupakan salah satu wilayah yang rawan terhadap tanah longsor. Peningkatkan kesiapsiagaan terhadap bahaya tanah longsor, dapat mengurangi dampak yang ditimbulkan dari bencana tersebut. Penelitian ini bertujuan mengetahui pengaruh penggunaan media komik terhadap kesiapsiagaan siswa dalam menghadapi bencana tanah longsor. Jenis penelitian adalah pre-experimental design dengan rancangan one-roup pretest-posttest menggunakan teknik total sampling dengan jumlah sampel sebanyak 57 orang. Pengumpulan data dilakukan dengan menggunakan kuisioner kesiapsiagaan bencana tanah longsor dan dianalisa dengan uji paired t-test. Hasil penelitian menunjukkan bahwa skor rata-rata kesiapsiagaan siswa sebelum perlakuan 69,68 dan setelah perlakuan sebesar 76,63 dengan selisih rata-rata sebelum dan sesudah perlakuan sebesar 6,94 dengan p value 0,001 sehingga disimpulkan ada pengaruh penggunaan media komik terhadap kesiapsiagaan siswa dalam menghadapi bencana tanah longsor di SDN 1 Sukawana.Kata kunci: bencana tanah longsor; kesiapsiagaan; media komik The Use Of Comics On Student Preparedness In Facing Landslide DisasterABSTRACT Landslides are an annual disaster that always hits parts of Indonesia. The occurrence of landslides can have a huge impact on both life and the environment. Based on data from the Center for Volcanology and Geological Hazard Mitigation, there were 918 landslide-prone locations spread across various regions in Indonesia. Bali Province is one of the areas prone to landslides. Increasing preparedness against landslides can reduce the impact of the disaster. This study was aimed to determine the effect of using comic’s media on student preparedness in dealing with landslides. This type of research was a pre-experimental design with a one-group pretest-posttest design using a total sampling technique with a total sample of 57 people. Data was collected using a landslide disaster preparedness questionnaire, and it was tested by using a paired t-test. The results show the average score of students' preparedness before treatment is 69.68 and after treatment is 76.63 with an average difference before and after treatment of 6.94 with p-value = 0.001. It was concluded that there was an effect of using comic’s media on students' preparedness in dealing with landslides at SDN 1 Sukawana. Keywords: landslide disaster; preparedness; comics’ media

Abstract In 2013, a pre-project activity of Experimental Power Reactor (RDE Project) was started. The reactor type is a High Temperature Gas-cooled Reactor (HTGR) with a 10 MWth capacity. At present the project has been postponed due to some reason, however, there was an important stage that has been achieved, regarding the site evaluation process to obtain site permits from the Regulatory Body (BAPETEN). Site evaluation is an critical activity that will guarantee the safety of nuclear facilities from natural and human induced external events as well as the safety of population and the environment due to nuclear facility accidents. Site evaluation for the RDE project has the same process as a large NPP project, considering that at the time of the site evaluation process there were no specific regulations that considered a graded approach for a mini-scale NPP. The site evaluation process includes two stages, namely 1). Site Evaluation Program (SEP) and Management System of Site Evaluation (MSSE) Approval and 2) Site Evaluation Approval. SEP is intended to establish the scope and criteria for site evaluation safety. Whereas the Site Evaluation Management System is a managerial instrument that makes site safety as the top priority in each activity and process of RDE site evaluation. BATAN as the project owner delivered the SEP document and MSSE to BAPETEN on March 10, 2014. These documents was intensively discussed by BAPETEN and BATAN to determine agreement on the scope of site evaluation, criteria and management aspects based on site safety considerations. The technical aspects that must be evaluated are seismicity, volcanic hazard, geotechnical and foundation, meteorology, hydrology, human induced events, dispersion and population distribution. This document was approved by BAPETEN on March 2, 2015. Considering the very wide scope with various fields of competence and need supporting data for evaluation, this can not be done only by BATAN experts, it must collaborate with various institution that have competence related to the site aspect. The experts that involved in the site evaluation come from Meteorology and Geophysics Agency (BMKG) for seismic and meteorological aspects, Geospatial Information Agency (BIG) to support geospatial data and ground movements/deformation, Geological Survey Center (PSG) to support geological data and geological structures, Center for Volcanology and Geological Disaster Mitigation (PVMBG) to support volcanic catalog data and volcanic hazard, University to support geotechnical, foundation and hydrology evaluation. BATAN experts from various Centers involved for evaluating topography, human induced events, dispersion, dose assessment, population distribution, emergency preparedness, and technology aspects. Data acquisition activities such as geophysics, drilling, geological mapping, volcanic mapping, hydrology, satellite imagery and digitizing processes are contracted through third parties with guidance developed by the BATAN Expert Team. Considering the very limited time and financial resources availability, in order to achieve the effectiveness of all activities, a special organization was formed to control site evaluation with the BATAN Chairman as Top Management. The Site evaluation document was submitted in two stages. The first stage is administrative completeness and it was declared administratively complete on November 15, 2015. The second step is BAPETEN assessed and evaluated the technical documents submitted to determine the acceptability of the site. The process of evaluating the site evaluation document lasts quite a long and intensive. Finally, the site permit was issued on January 23, 2017. The valuable lessons during the site evaluation project are: 1) It require the same understanding and perception between applicant and regulator regarding the site licensing process; 2) The establishment and implementation of an effective organization; 3) controlling the project schedule.

Study of petrological and geochemical characteristics of mantle peridotite xenoliths in Pliocene alkaline basalt in Nghia Dan (West Nghe An) was carried out. Rock-forming clinopyroxenes, the major trace element containers, were separated from the xenoliths to analyze for major, trace element and Sr-Nd isotopic compositions. The data were interpreted for source geochemical characteristics and geodynamic processes of the lithospheric mantle beneath the region. The peridotite xenoliths being mostly spinel-lherzolites in composition, are residual entities having been produced following partial melting events of ultramafic rocks in the asthenosphere. They are depleted in trace element abundance and Sr-Nd isotopic composition. Some are even more depleted as compared to mid-ocean ridge mantle xenoliths. Modelled calculation based on trace element abundances and their corresponding solid/liquid distribution coefficients showed that the Nghia Dan mantle xenoliths may be produced of melting degrees from 8 to 12%. Applying various methods for two-pyroxene temperature- pressure estimates, the Nghia Dan mantle xenoliths show ranges of crystallization temperature and pressure, respectively, of 1010-1044°C and 13-14.2 kbar, roughly about 43km. A geotherm constructed for the mantle xenoliths showed a higher geothermal gradient as compared to that of in the western Highlands (Vietnam) and a conductive model, implying a thermal perturbation under the region. The calculated Sm-Nd model ages for the clinopyroxenes yielded 127 and 122 Ma. If the age is meaningful it suggests that there was a major geodynamic process occurred beneath Western Nghe An in the middle- Early Cretaceous that was large enough to cause perturbation in the evolutional trend of the Sm-Nd isotopic system.ReferencesAn A-R., Choi S.H., Yu Y-g., Lee D-C., 2017. Petrogenesis of Late Cenozoic basaltic rocks from southern Vietnam. Lithos, 272-273 (2017), 192-204.Anders E., Grevesse N., 1989. Abundances of the elements: meteorite and solar. Geochimica et Cosmochimica Acta, 53, 197-214.Anderson D.L, 1994. The subcontinental mantle as the source of continental flood basalts; the case against the continental lithosphere mantle and plume hear reservoirs. Earth and Planetary Science Letter, 123, 269-280.Arai S., 1994. Characterization of spinel peridotites by olivine-spinel compositional relationships: review and interpretation. Chemical Geology, 113, 191-204.Ballhaus C., Berry R.G., Green D.H., 1991. High pressure experimental calibration of the olivine orthopyroxene-spinel oxygen geobarometer: implications for the oxidation state of the upper mantle. Contributions to Mineralogy and Petrology, 107, 27-40.Barr S.M. and MacDonald A.S., 1981. Geochemistry and geochronology of late Cenozoic basalts of southeast Asia: summary. Geological Society of America Bulletin, 92, 508-512.Brey G.P., Köhler T., 1990. Geothermobarometry in four-phase lherzolite II. New thermobarometers, and practical assessment of existing thermobarometers. Journal of Petrology, 31, 1353-1378.Briais A., Patriat P., Tapponnier P., 1993. Updated interpretation of magnetic anomalies and seafloor spreading stages in the South China Sea, implications for the Tertiary tectonics of SE Asia. Journal of Geophysical Research, 98, 6299-6328.Carlson R.W., Irving A.J., 1994. Depletion and enrichment history of subcontinental lithospheric mantle: an Os, Sr, Nd and Pb isotopic study of ultramafic xenoliths from the northwestern Wyoming Craton. Earth and Planetary Science Letters, 126, 457-472.Carlson R.W., Lugmair G.W., 1979. Sm-Nd constraints on early lunar differentiation and the evolution of KREEP. Earth and Planetary Science Letters, 45, 123-132.Carlson R.W., Lugmair G.W., 1981. Sm-Nd age of lherzolite 67667: implications for the processes involved in lunar crustal formation. Earth and Planetary Science Letters, 56, 1-8.Choi H.S., Mukasa S.B., Zhou X-H., Xian X-G.H., Andronikov A.V., 2008. Mantle dynamics beneath East Asia constrained by Sr, Nd, Pb and Hf isotopic systematics of ultramafic xenoliths and their host basalts from Hannuoba, North China. Chemical Geology, 248, 40-61.Choi S.H., Jwa Y.-J., Lee H.Y., 2001. Geothermal gradient of the upper mantle beneath Jeju Island, Korea: evidence from mantle xenoliths. Island Arc, 10, 175-193.Choi S.H., Kwon S-T., Mukasa S.B., Sagon H., 2005. Sr-Nd-Pb isotope and trace element systematics of mantle xenoliths from Late Cenozoic alkaline lavas, South Korea. Chemical Geology, 22, 40-64.Cox K.G., Bell J.D., Pankhurst R.J., 1979. The Interpretation of Igneous Rocks. George Allen & Unwin.Cung Thuong Chi, Dorobek S.L., Richter C., Flower M., Kikawa E., Nguyen Y.T., McCabe R., 1998. Paleomagnetism of Late Neogene basalts in Vietnam and Thailand: Implications for the Post-Miocene tectonic history of Indochina. In: Flower M.F.J., Chung, S.L., Lo, C.H., (Eds.). Mantle Dynamics and Plate Interactions in East Asia. Geodynamics Ser, American Geophysical Union, 27, 289-299.De Hoog J.C.M., Gall L., Cornell D.H., 2010. Trace-element geochemistry of mantle olivine and application to mantle petrogenesis and geothermobarometry. Chemical Geology, 270, 196-215.DePaolo D. J., 1981. Neodymium isotopes in the Colorado Front Range and crust - mantle evolution in the Proterozoic. Nature, 291, 193-197.DePaolo D.J., Wasserburg G.J., 1976. Nd isotopic variations and petrogenetic models. Geophysical Research Letters, 3(5), 249-252. Doi: https://doi.org/10.2113/gselements.13.1.11.Embey-Isztin A., Dobosi G., Meyer H.-P., 2001. Thermal evolution of the lithosphere beneath the western Pannonian Basin: evidence from deep-seat xenoliths. Tectonophysics, 331, 285-306.Fedorov P.I., Koloskov A.V., 2005. Cenozoic volcanism of Southeast Asia. Petrologiya, 13(4), 289-420.Frey F.A., Prinz M., 1978. Ultramafic inclusions from San Carlos, Arizona: Petrologic and geochemical data bearing on their Petrogenesis. Earth and Planetary Science Letters, 38, 129-176.Garnier V., Ohmenstetter D., Giuliani G., Fallick A.E., Phan T.T., Hoang Q.V., Pham V.L., Schawarz D., 2005. Basalt petrology, zircon ages and sapphire genesis from Dak Nong, southern Vietnam. Mineralogical Magazine, 69(1), 21-38.Gast P.W., 1968. Trace element fractionation and the origin of tholeiitic and alkaline magma types. Geochimica et Cosmochimica Acta, 32, 1057-1086.Gorshkov A.P, Ivanenko A.N., Rashidov V.A., 1984. Hydro-magnetic investigations of submarine volcanic zones in the marginal seas of Pacific Ocean (Novovineisky and Bien Dong seas). Pacific Ocean Geology, 1, 13-20.Gorshkov A.P., 1981. Investigation of submarine volcanoes during the 10th course of scientific research vessel ‘Volcanolog’. Volcanology and Seismology, 6, 39-45 (in Russian).Hart S.R., 1988. Heterogeneous mantle domains: signatures, genesis and mixing chronologies. Earth and Planetary Science Letters, 90, 273-296.Hirose K., Kushiro I., 1993. Partial melting of dry peridotites at high pressures: determination of composition of melts segregated from peridotite using aggregate of diamond. Earth Planet Science Letters, 114, 477-489.Hoang-Thi H.A., Choi S.H., Yongjae Yu Y-g., Pham T.H., Nguyen K.H., Ryu J-S., 2018. Geochemical constraints on the spatial distribution of recycled oceanic crust in the mantle source of late Cenozoic basalts, Vietnam. Lithos, 296-299 (2018), 382-395.Izokh A.E., Smirnov S.Z., Egorova V.V., Tran T.A., Kovyazin S.V., Ngo T.P., Kalinina V.V., 2010. The conditions of formation of sapphire and zircon in the areas of alkali-basaltoid volcanism in Central Vietnam. Russian Geology and Geophysics, 51(7), 719-733.Johnson K.T., Dick H.J.B. and Shimizu N., 1990. Melting in the oceanic upper mantle: An ion microprobe study of diopsides in abyssal peridotites. Journal of Geophysical Research (solid earth), 95, 2661-2678.Kölher T.P., Brey G.P., 1990. Calcium exchange between olivine and clinopyroxene calibrated as a geothermobarometer for natural peridotites from 2 to 60 kb with applications. Geochimica et Cosmochimica Acta, 54(9), 2375-2388.Kushiro I., 1996. Partial melting of a fertile mantle peridotite at high pressure: An experimental study using aggregates of diamond. In: A. Basu and S.R. Hart (Eds.), Earth Processes: Reading the Isotopic Code. AGU Monograph, 95, 109-122.Kushiro I., 1998. Compositions of partial melts formed in mantle peridotites at high pressures and their relation to those of primitive MORB. Physics of Earth and Planetary Interiors, 107, 103-110.Latin D., White N., 1990. Generating melt during lithospheric extension: Pure shear vs. simple shear. Geology, 18, 327-331.Lee T.-y. and Lawver L., 1995. Cenozoic plate reconstruction of Southeast Asia. In: M.F.J. Flower, R.J. McCabe and T.W.C. Hilde (Editors), Southeast Asia Structure, Tectonics, and Magmatism. Tectonophysics, 85-138.Li C-F., et al., 2015. Seismic stratigraphy of the central South China Sea basin and implications for neotectonics. Journal of Geophysical Research (solid earth), 120, 1377-1399. Doi:10.1002/2014JB011686.Li C.-F., et al., 2014. Ages and magnetic structures of the South China Sea constrained by deep tow magnetic surveys and IODP Expedition 349 Geochemistry, Geophysics, Geosystems, 14, 4958-4983.Malinovsky A.I., Rashidov V.A., 2015. Compositional characteristics of sedimentary and volcano-sedimentary rocks of Phu Quy-Catwick island group in the continental shelf of Vietnam. Bulletin of Kamchatka Regional Association of ‘Educational - Scientific’ Center, Earth Sciences, 27(3), 12-34 (in Russian with English summary).McCulloch M.T., Wasserburg G.J., 1978. Sm-Nd and Rb-Sr chronology of continental crust formation. Science, 200(4345), 1003-1011.Menzies M.A., Arculus R.L., Best M.G., et al., 1987. A record of subduction process and within-plate volcanism in lithospheric xenoliths of the southwestern USA. In P.H. Nixon (Editor), Mantle Xenoliths, John Wiley & Sons, Chichester, 59-74.Nguyen Hoang, Ogasawara M., Tran Thi Huong, Phan Van Hung, Nguyen Thi Thu, Cu Sy Thang, Pham Thanh Dang, Pham Tich Xuan, 2014. Geochemistry of Neogene Basalts in the Nghia Dan district, western Nghe An. J. Sci. of the Earth, 36, 403 -412.Nguyen Kinh Quoc, Nguyen Thu Giao, 1980. Cenozoic volcanic activity in Viet Nam. Geology and Mineral Resources, 2, 137-151 (in Vietnamese with English abstract).Nixon P.H., 1987 (Editor). Mantle xenoliths. John Wiley and Sons, 844p.Norman M.D. and Garcia M.O., 1999. Primitive magmas and source characteristics of the Hawaiian plume: petrology and geochemistry of shield picrites. Earth and Planetary Science Letters, 168, 27-44.Pollack H.N., Chapman D.S., 1977. On the regional variation of heat flow, geotherms and lithospheric thickness. Tectonophysics, 38, 279-296.Putirka K., 2008. Thermometers and Barometers for Volcanic Systems. In: Putirka, K., Tepley, F. (Eds.), Minerals, Inclusions and Volcanic Processes, Reviews in Mineralogy and Geochemistry, Mineralogical Soc. Am., 69, 61-120. Putirka K.D., 2017. Down the craters: where magmas stored and why they erupt. Methods and Further Reading. Supplement to February 2017 issue of Elements, 3(1), 11-16.Putirka K.D., Johnson M., Kinzler R., Longhi J., Walker D., 1996. Thermobarometry of mafic igneous rocks based on clinopyroxene-liquid equilibria, 0-30 kbar. Contributions to Mineralogy and Petrology, 123, 92-108. Putirka K.D., Mikaelian H., Ryerson F., Shaw H., 2003. New clinopyroxene-liquid thermobarometers for mafic, evolved, and volatile-bearing lava compositions, with applications to lavas from Tibet and the Snake River Plain, Idaho. American Mineralogist, 88, 1542-1554. Qi Q., Taylor L.A., Zhou X., 1995. Petrology and geochemistry of mantle peridotite xenoliths from SE China. Journal of Petrology, 36, 55-79.Sachtleben T.H., Seck H.A., 1981. Chemical control on the Al-solubility in orthopyroxene and its implications on pyroxene geothermometry. Contributions to Mineralogy and Petrology, 78, 157-65.Shaw D.M., 1970. Trace element fractionation during anataxis. Geochimica et Cosmochimica Acta, 34, 237-243.Sun S-S, McDonough W.F., 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Saunders A.D. and Norry, M.J. (eds) Magmatism in the Ocean Basins. Geological Society Special Publication, 42, 313-345.Takahashi E., 1986. Melting of a dry peridotite KLB-1 up to 14 Gpa: implications on the origin of peridotite upper mantle. J. Geophysical Research, 91, 9367-9382.Takahashi E., Kushiro I., 1983. Melting of a dry peridotite at high pressure and basalt magma genesis. American Mineralogist, 68, 859-879.Tamaki K., 1995. Upper mantle extrusion tectonics of southeast Asia and formation of western Pacific backarc basins. In: International Workshop: Cenozoic Evolution of the Indochina Peninsula, Hanoi/Do Son, April, p.89 (Abstract with Programs).Tapponnier P., Lacassin R., Leloup P.H., Shärer U., Dalai Z., Haiwei W., Xiaohan L., Shaocheng J., Lianshang Z., Jiayou Z., 1990. The Ailao Shan/Red River metamorphic belt: Tertiary left-lateral shear between Indochina and South China. Nature, 343(6257), 431-437.Tapponnier P., Peltzer G., La Dain A.Y., Armijo R., Cobbold P., 1982. Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine. Geology, 7, 611-616.Tatsumoto M., Basu A.R., Huang W., Wang J., Xie G., 1992. Sr, Nd, and Pb isotopes of ultramafic xenoliths in volcanic rocks of eastern China: enriched components EMI and EMII in subcontinental lithosphere. Earth Planet Sci. Letters, 113, 107-128.Taylor S.R., McLennan S.M., 1981. The composition and evolution of the continental crust: rare earth element evidence from sedimentary rocks. Philosophical Transactions of the Royal Society of London, 301, 381-399.Tu K., Flower M.F.J., Carlson R.W., Xie G-H., 1991. Sr, Nd, and Pb isotopic compositions of Hainan basalt (south China): Implications for a subcontinental lithosphere Dupal source. Geology, 19, 567-569.Tu K., Flower M.F.J., Carlson R.W., Xie G-H., Zhang M., 1992. Magmatism in the South China Basin 1. Isotopic and trace-element evidence for an endogenous Dupal component. Chemical Geology, 97, 47-63.Warren J.M., 2016. Global variations in abyssal peridotite compositions. Lithos, 248-251, 193-219.Webb S.A., Wood B.J., 1986. Spinel pyroxene- garnet relationships and their dependence on Cr/Al ratio. Contributions to Mineralogy and Petrology, 92, 471-480.Wells P.R.A., 1977. Pyroxene thermometry in simple and complex systems. Contributions to Mineralogy and Petrology, 62, 129-139.Whitford-Stark J.L., 1987. A survey of Cenozoic olcanism on mainland Asia, special paper, 213. Geological Society of America, 74p.Workman R.K., Hart S.R., 2005. Major and trace element composition of the depleted MORB mantle (DMM). Earth and Planetary Science Letters, 231, 53-72.Zhou P., Mukasa S., 1997. Nd-Sr-Pb isotopic, and major- and trace-element geochemistry of Cenozoic lavas from the Khorat Plateau, Thailand, sources and petrogenesis. Chemical Geology, 137, 175-193.Zindler A., Hart S.R., 1986. Chemical geodynamics. Annual Review of Earth and Planetary Sciences, 14, 493-571.

AbstractQuantitative shape analysis of juvenile pyroclasts is applied in volcanology to reconstruct the dynamics and styles of eruptions, and to explore the details of tephra transport, dispersal, and emplacement. Morphometric analyses often include comparison of multiple data sets with a set of dimensionless shape parameters. Here we present “DendroScan”, an open source Matlab program that provides the user with all the multivariate statistical methods needed to produce such morphometric comparisons. Serving as a statistical “toolbox”, DendroScan conducts Levene-, t-, and equivalence tests, presenting the results in ad hoc interpretable graphs. Furthermore, it is designed to conduct dendrogrammatic analyses of particle morphometry, a recently developed approach for the inter-comparison of multiple morphometric data sets. DendroScan produces tree diagrams, in which the analysed samples are sorted according to their morphometric dissimilarity, allowing the user to identify, e.g., samples that are statistically equivalent. To demonstrate DendroScan’s potential, ten experimental samples are compared with volcanic ash samples generated by the Havre 2012 deep-sea eruption in the Kermadec arc (New Zealand). We show how, using DendroScan-based results, information on the eruptive mechanism can be inferred, and how the cooling history of the experimental melt is reflected in the dissimilarity of thermally granulated fragments.

AbstractLaterally directed explosive eruptions are responsible for multiple fatalities over the past decade and are an increasingly important volcanology problem. To understand the energy dynamics for these events, we collected field-scale explosion data from nine acoustic sensors surrounding a tiltable cannon as part of an exploratory experimental design. For each cannon discharge, the blast direction was varied systematically at 0°, 12°, and 24° from vertical, capturing acoustic wavefield directivity related to the tilt angle. While each event was similar in energy discharge potential, the resulting acoustic signal features were variable event-to-event, producing non-repetitious waveforms and spectra. Systematic features were observed in a subset of individual events for vertical and lateral discharges. For vertical discharges, the acoustic energy had a uniform radiation pattern. The lateral discharges showed an asymmetric radiation pattern with higher frequencies in the direction of the blast and depletion of those frequencies behind the cannon. Results suggest that, in natural volcanic systems, near-field blast directionality may be elucidated from acoustic sensors in absence of visual data, with implications for volcano monitoring and hazard assessment. Graphical Abstract

AbstractThis review summarizes what the volcanology community has learned thus far from studying the deposits of pyroclastic currents (PCs) from the 1980 eruption sequence at Mount St. Helens. The review includes mass flow events during the May 18 eruption, including the lateral blast, the afternoon column collapse and boil-over PC activity, and some aspects of the debris avalanche. We also include a summary of PCs generated in the smaller eruptions following the climactic May 18 event. Our objective is to summarize the state of our understanding of PC transport and emplacement mechanisms from the combination of field and laboratory observations, granular flow experiments, and numerical modeling techniques. Specifically, we couple deposit characteristics, experiments, and numerical modeling techniques to critically address the problems of (1) constraining conditions in the flow boundary zone at the time of deposition; (2) the influence of substrate roughness and topography on PC behavior; (3) the prevalence, causes, and consequences of substrate erosion by PCs; and (4) the reconstruction of PC transportation and sedimentation processes from a combination of geophysical and sedimentological observations. We conclude by providing opportunities for future research as our field, experimental, and numerical research techniques advance.

<p>Following the Ml 5.9 earthquake that struck the Emilia area in northern Italy on May 20, 2012, at 02:03:53 UTC, and in co-operation with the personnel of the Municipality of Ferrara and the University of Ferrara, a team of seismologists of the Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS; National Institute of Oceanography and Experimental Geophysics) deployed a temporary seismographic network. This consisted of eight portable seismological stations, to record the local earthquakes that occurred during the seismic sequence. The OGS intervention was integrated into the broader action of the emergency response to the earthquake sequence, which was promoted by the National Department of Civil Protection and the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology) [Moretti et al. 2012, this volume]. The aim of the OGS intervention was on the one hand to extend the seismic monitoring area towards the East, to include Ferrara and its surroundings, to be ready in case of migration of the seismicity in that direction, and on the other hand to evaluate the seismic response at the instrumented sites. Some days later, another team of researchers coordinated by the University of Potenza carried out some investigations at a number of sites, and in particular at three of the sites instrumented by the OGS temporary network. […]</p><p> </p>

Abstract Metallogeny is the science of ore and mineral deposit formation in geological space and time. Metallogeny is interdisciplinary by nature, comprising elements of natural science disciplines such as planetology to solid state physics and chemistry, and volcanology. It is the experimental forefront of research and bold thinking, based on an ever-growing foundation of solid knowledge. Therefore, metallogeny is not a closed system of knowledge but a fast-growing assemblage of structured and unstructured information in perpetual flux. This paper intends to review its current state and trends. The latter may introduce speculation and fuzziness. Metallogeny has existed for over 100 years as a branch of Earth Science. From the discovery of plate tectonics (ca. 1950) to the end of the last century, metallogeny passed through a worldwide phase of formally published ‘metallogenetic’ maps. In the last decades, a rapidly growing number of scientists, digitization and splendid new tools fundamentally boosted research. More innovations may be expected by the growing use of an evolving systematic ‘Geodata Science’ for metallogenic research by an increasingly global human talent pool. Future requirements for metallic and mineral raw materials, especially the critical natural elements and compounds that are needed for the nascent carbon-free economy, already drive activities on stock markets and in the resource industry. State geological surveys, academia and private companies embrace the challenges. The new age requires intensified metallogenic backing. In this paper, principles of metallogeny are recalled concerning concepts and terms. A metallogenic classification of ore and mineral deposits is proposed, and the intimate relations of metallogenesis with geodynamics are sketched (ancient lid tectonics and modern plate tectonics). Metallogenic models assemble a great diversity of data that allow an ever better understanding of ore formation, foremost by illuminating the geological source-to-trap migration of ore metals, the petrogenetic and geodynamic–tectonic setting, the spatial architecture of ore deposits and the nature and precise timing of involved processes. Applied metallogeny allows companies to choose strategy and tactics for exploration investment and for planning the work. Based on comprehensive metallogenic knowledge, mineral system analysis (MSA) selects those elements of complex metallogenic models, which are detectable and can guide exploration in order to support applications such as mineral prospectivity mapping, mineral potential evaluation and targeting of detailed investigations. MSA founded on metallogenic models can be applied across whole continents, or at the scale of regional greenfield search, or in brownfields at district to camp scale. By delivering the fundamental keys for MSA, supported by unceasing innovative research, the stream of new metallogenic insights is essential for improving endowment estimates and for successful exploration.

Abstract We present a detailed petrologic study of rhyolites from seven eruptions spanning the full (∼190 k.y.) history of rhyolitic volcanism at Krafla volcano, northeast Iceland. The eruptions vary widely in size and style, but all rhyolites are crystal-poor (&lt;6 modal%: plagioclase + augite ± pigeonite ± orthopyroxene ± titanomagnetite ± fayalite) and have similar evolved compositions (73.7–75.8 wt% normalised whole-rock SiO2) and trace element patterns. Macrocryst rim compositions from each eruption cluster within a narrow range and are appropriate for equilibrium with their carrier melt. Crystal cores and interiors display complex growth patterns and commonly host resorption surfaces, but compositional variations are slight (e.g., typically &lt;10 mol% An for plagioclase, Mg# &lt;10 for pyroxene), and consistent with an overall trend of cooling and differentiation by crystal fractionation. Although most crystal core and interior compositions are broadly appropriate for equilibrium with melts similar to their host whole-rock, variable growth histories, juxtaposition of grains with distinct trace element compositions, and scatter in melt inclusion compositions imply mixing of antecrysts from compositionally similar evolved melts and/or assimilated felsic mush or intrusions before final rim growth. Evidence for mafic recharge (e.g., coupled increases in An and Fe in plagioclase) is absent in most crystals; rhyolite storage and fractionation thus occurred largely in isolation from the underlying mafic system. Comparison of observed matrix glass compositions with published experimental work on melting of altered (meta)basalts casts doubt on prior models favouring rhyolite generation by partial melting of hydrothermally altered basalts, instead supporting recent isotopic and modeling arguments for a crystallisation-driven process [Hampton, R. L. et al. (2021). Journal of Volcanology and Geothermal Research 414, 107229]. MELTS fractional crystallisation and assimilation-fractional crystallisation (AFC) models at 1 kbar predict liquid major and trace element compositions similar to Krafla rhyolites after ∼60–70 vol% crystallisation of a quartz tholeiite melt representative of the evolved crystal-poor basalts commonly erupted within Krafla caldera. We thus suggest that stalling and crystallisation of these evolved basalts at shallow depth forms crystal mushes from which evolved (broadly dacitic to rhyolitic) melts are extracted. These melts ascend and mix with other compositionally similar melt bodies and/or assimilate felsic intrusive material in the uppermost crust. The Daly gap between ∼57–71 wt% SiO2 at Krafla is consistent with preferential extraction of evolved melts from quartz tholeiite mushes in the ∼50–70% crystallinity window. Residual solid (cumulate) compositions predicted by MELTS are exclusively mafic, hence efficient silicic melt extraction from quartz tholeiite mushes may also explain the apparent compositional bimodality in some Icelandic plutonic suites.

Abstract How silicic magmas are stored in the upper crust before they erupt to form 100-1000s km3 ash-sheets remains a fundamental, but unanswered question in volcanology. While some studies posit storage in an eruptible state at low viscosity (&lt;50% crystals) and high temperatures (&gt;760-740°C) (warm storage), others suggest storage in a rigid state (&gt;50% crystals) at lower, near-solidus temperatures (cold storage). Storage temperature and time spent near the solidus are typically constrained by mineral thermometry and diffusional relaxation modelling (at a given temperature), respectively. Since quartz is abundant over a range of temperatures and compositions and can incorporate titanium (Ti) at magmatic temperatures, a Ti-in-Quartz thermometer has been calibrated and Ti diffusion coefficients (DTi) have been measured. However, simply applying this thermometer or diffusion coefficient to volcanic quartz is burdened by an ongoing debate regarding their experimental calibration. This debate centers around three recent Ti-in-Quartz thermometers by Huang & Audétat (2012), Zhang et al. (2020), Osborne et al. (2022) and three DTi by Cherniak et al. (2007), Jollands et al. (2020), Audétat et al. (2021), each of which when applied to igneous systems favors either warm or cold storage. To determine their applicability for estimating the pre-eruptive thermal history of silicic magmatic systems, we apply the different Ti-in-Quartz thermometers and DTi to quartz from the Fish Canyon Tuff (USA). This tuff is an optimal location for such a study because it is a prime example of cold storage with multiple previous studies providing constraints on its storage conditions. We find that a temperature of 737 ± 16°C using the Zhang et al. (2020) thermometer is the most consistent with other temperature estimates for the Fish Canyon Tuff. Temperatures calculated using Huang & Audétat (2012) are acceptable, while those using Osborne et al. (2022) are unrealistic. Applying each of the DTi to quartz in the Fish Canyon Tuff and comparing these timescales to timescales from Ba-in-Sanidine diffusion and the total storage time of the mush (derived from the range in zircon U-Pb ages and the local eruption history), three different scenarios for pre-eruptive storage are possible. At a temperature of 737°C, timescales using DTi by Audétat et al. (2021) exceed the total storage time of the Fish Canyon system by ~2 Myr. These DTi are only consistent if storage temperatures were significantly higher, implying warm storage. Such a scenario is inconsistent with cold storage of the Fish Canyon system. Timescales derived from DTi by Jollands et al. (2020) and Cherniak et al. (2007) are consistent with cold storage of the Fish Canyon system. While DTi by Jollands et al. (2020) suggest long-term storage near 737°C and an extended period of pre-eruptive reheating, DTi by Cherniak et al. (2007) suggests storage below 737°C and rapid reheating.