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Zundel M, Spiegel C, Mark C, Millar I, Chew D, Klages J, Gohl K, Hillenbrand CD, Najman Y, Salzmann U, Ehrmann W, Titschack J, Bauersachs T, Uenzelmann-Neben G, Bickert T, Müller J, Larter R, Lisker F, Bohaty S, Kuhn G. A large-scale transcontinental river system crossed West Antarctica during the Eocene. SCIENCE ADVANCES 2024; 10:eadn6056. [PMID: 38838149 DOI: 10.1126/sciadv.adn6056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/24/2024] [Indexed: 06/07/2024]
Abstract
Extensive ice coverage largely prevents investigations of Antarctica's unglaciated past. Knowledge about environmental and tectonic development before large-scale glaciation, however, is important for understanding the transition into the modern icehouse world. We report geochronological and sedimentological data from a drill core from the Amundsen Sea shelf, providing insights into tectonic and topographic conditions during the Eocene (~44 to 34 million years ago), shortly before major ice sheet buildup. Our findings reveal the Eocene as a transition period from >40 million years of relative tectonic quiescence toward reactivation of the West Antarctic Rift System, coinciding with incipient volcanism, rise of the Transantarctic Mountains, and renewed sedimentation under temperate climate conditions. The recovered sediments were deposited in a coastal-estuarine swamp environment at the outlet of a >1500-km-long transcontinental river system, draining from the rising Transantarctic Mountains into the Amundsen Sea. Much of West Antarctica hence lied above sea level, but low topographic relief combined with low elevation inhibited widespread ice sheet formation.
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Affiliation(s)
| | | | - Chris Mark
- School of Earth Sciences, University College Dublin, Belfield, Dublin, Ireland
| | - Ian Millar
- British Geological Survey, Keyworth, Nottingham, UK
| | - David Chew
- Department of Geology, Trinity College Dublin, College Green, Dublin, Ireland
| | - Johann Klages
- Department of Geosciences, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | - Karsten Gohl
- Department of Geosciences, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | | | - Yani Najman
- Lancaster University, Lancaster Environment Centre, Lancaster, UK
| | - Ulrich Salzmann
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Werner Ehrmann
- Institute for Geophysics and Geology, University of Leipzig, Leipzig, Germany
| | - Jürgen Titschack
- MARUM-Center for Marine Environmental Sciences, Bremen, Germany
- Marine Research Department, Senckenberg am Meer, Wilhelmshaven, Germany
| | - Thorsten Bauersachs
- Institute of Organic Biogeochemistry in Geo-Systems, RWTH Aachen University, Aachen, Germany
| | - Gabriele Uenzelmann-Neben
- Department of Geosciences, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | - Torsten Bickert
- MARUM-Center for Marine Environmental Sciences, Bremen, Germany
| | - Juliane Müller
- Department of Geosciences, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | | | - Frank Lisker
- Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Steve Bohaty
- Institute of Earth Sciences, University of Heidelberg, Heidelberg, Germany
| | - Gerhard Kuhn
- Faculty of Geosciences, University of Bremen, Bremen, Germany
- Department of Geosciences, Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
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2
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Clerc F, Behn MD, Minchew BM. Deglaciation-enhanced mantle CO 2 fluxes at Yellowstone imply positive climate feedback. Nat Commun 2024; 15:1526. [PMID: 38378722 PMCID: PMC10879189 DOI: 10.1038/s41467-024-45890-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
Mantle melt generation in response to glacial unloading has been linked to enhanced magmatic volatile release in Iceland and global eruptive records. It is unclear whether this process is important in systems lacking evidence of enhanced eruptions. The deglaciation of the Yellowstone ice cap did not observably enhance volcanism, yet Yellowstone emits large volumes of CO2 due to melt crystallization at depth. Here we model mantle melting and CO2 release during the deglaciation of Yellowstone (using Iceland as a benchmark). We find mantle melting is enhanced 19-fold during deglaciation, generating an additional 250-620 km3. These melts segregate an additional 18-79 Gt of CO2 from the mantle, representing a ~3-15% increase in the global volcanic CO2 flux (if degassed immediately). We suggest deglaciation-enhanced mantle melting is important in continental settings with partially molten mantle - including Greenland and West Antarctica - potentially implying positive feedbacks between deglaciation and climate warming.
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Affiliation(s)
- Fiona Clerc
- Previously at: MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering, Cambridge, MA, USA.
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA.
| | - Mark D Behn
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, USA
| | - Brent M Minchew
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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Jordan TA, Thompson S, Kulessa B, Ferraccioli F. Geological sketch map and implications for ice flow of Thwaites Glacier, West Antarctica, from integrated aerogeophysical observations. SCIENCE ADVANCES 2023; 9:eadf2639. [PMID: 37256953 PMCID: PMC10413667 DOI: 10.1126/sciadv.adf2639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 04/25/2023] [Indexed: 06/02/2023]
Abstract
The geology beneath Thwaites Glacier, the Antarctic glacial catchment most vulnerable to climate change, is unknown. Thwaites Glacier lies within the West Antarctic Rift System, but details of the subglacial geology relevant to glacial flow, including sediment availability, underlying lithology, and heat flux, are lacking. We present the first sketch map of the subglacial geology of Thwaites Glacier, interpreted from maps of airborne gravity, magnetic and radar data, supported by 2D models and 3D inversion of subsurface properties, and the regional geological context. A zone of Cretaceous mafic magmatism extending ~200 km inland from the coast is interpreted, while sedimentary basins are restricted to a region 150 to 200 km inboard of the coast, underlying just 20% of the catchment. Several granitic subglacial highlands are identified, forming long-lived topographic highs. Our geological interpretation places constraints on the basal properties of Thwaites Glacier, laying the foundation for both improved predictions of ice sheet change and studies of West Antarctic tectonics.
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Affiliation(s)
| | - Sarah Thompson
- Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Bernd Kulessa
- School of Biosciences, Geography and Physics, Swansea University, Swansea, UK
- School of Geography, Planning, and Spatial Sciences, University of Tasmania, Hobart, Australia
| | - Fausto Ferraccioli
- British Antarctic Survey, Cambridge, UK
- Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Borgo Grotta Gigante, Sgonico, Italy
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4
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A large West Antarctic Ice Sheet explains early Neogene sea-level amplitude. Nature 2021; 600:450-455. [PMID: 34912089 DOI: 10.1038/s41586-021-04148-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 10/14/2021] [Indexed: 11/08/2022]
Abstract
Early to Middle Miocene sea-level oscillations of approximately 40-60 m estimated from far-field records1-3 are interpreted to reflect the loss of virtually all East Antarctic ice during peak warmth2. This contrasts with ice-sheet model experiments suggesting most terrestrial ice in East Antarctica was retained even during the warmest intervals of the Middle Miocene4,5. Data and model outputs can be reconciled if a large West Antarctic Ice Sheet (WAIS) existed and expanded across most of the outer continental shelf during the Early Miocene, accounting for maximum ice-sheet volumes. Here we provide the earliest geological evidence proving large WAIS expansions occurred during the Early Miocene (~17.72-17.40 Ma). Geochemical and petrographic data show glacimarine sediments recovered at International Ocean Discovery Program (IODP) Site U1521 in the central Ross Sea derive from West Antarctica, requiring the presence of a WAIS covering most of the Ross Sea continental shelf. Seismic, lithological and palynological data reveal the intermittent proximity of grounded ice to Site U1521. The erosion rate calculated from this sediment package greatly exceeds the long-term mean, implying rapid erosion of West Antarctica. This interval therefore captures a key step in the genesis of a marine-based WAIS and a tipping point in Antarctic ice-sheet evolution.
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Assessing the Use of Optical Satellite Images to Detect Volcanic Impacts on Glacier Surface Morphology. REMOTE SENSING 2021. [DOI: 10.3390/rs13173453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Globally, about 250 Holocene volcanoes are either glacier-clad or have glaciers in close proximity. Interactions between volcanoes and glaciers are therefore common, and some of the most deadly (e.g., Nevado del Ruiz, 1985) and most costly (e.g., Eyjafjallajökull, 2010) eruptions of recent years were associated with glaciovolcanism. An improved understanding of volcano-glacier interactions is therefore of both global scientific and societal importance. This study investigates the potential of using optical satellite images to detect volcanic impacts on glaciers, with a view to utilise detected changes in glacier surface morphology to improve glacier-clad volcano monitoring and eruption forecasting. Roughly 1400 optical satellite images are investigated from key, well-documented eruptions around the globe during the satellite remote sensing era (i.e., 1972 to present). The most common observable volcanic impact on glacier morphology (for both thick and thin ice-masses) is the formation of ice cauldrons and openings, often associated with concentric crevassing. Other observable volcanic impacts include ice bulging and fracturing due to subglacial dome growth; localized crevassing adjacent to supraglacial lava flows; widespread glacier crevassing, presumably, due to meltwater-triggered glacier acceleration and advance. The main limitation of using optical satellite images to investigate changes in glacier morphology is the availability of cloud- and eruption-plume-free scenes of sufficient spatial- and temporal resolution. Therefore, for optimal monitoring and eruption prediction at glacier-clad volcanoes, optical satellite images are best used in combination with other sources, including SAR satellite data, aerial images, ground-based observations and satellite-derived products (e.g., DEMs).
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Seco J, Xavier JC, Coelho JP, Pereira B, Tarling G, Pardal MA, Bustamante P, Stowasser G, Brierley AS, Pereira ME. Spatial variability in total and organic mercury levels in Antarctic krill Euphausia superba across the Scotia Sea. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 247:332-339. [PMID: 30685674 DOI: 10.1016/j.envpol.2019.01.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/08/2019] [Accepted: 01/09/2019] [Indexed: 06/09/2023]
Abstract
Total and organic mercury concentrations were determined for males, females and juveniles of Euphausia superba collected at three discrete locations in the Scotia Sea (South Orkney Islands, South Georgia and Antarctic Polar Front) to assess spatial mercury variability in Antarctic krill. There was clear geographic differentiation in mercury concentrations, with specimens from the South Orkney Islands having total mercury concentrations 5 to 7 times higher than Antarctic krill from South Georgia and the Antarctic Polar Front. Mercury did not appear to accumulate with life-stage since juveniles had higher concentrations of total mercury (0.071 μg g-1 from South Orkney Islands; 0.014 μg g-1 from South Georgia) than adults (0.054 μg g-1 in females and 0.048 μg g-1 in males from South Orkney Islands; 0.006 μg g-1 in females and 0.007 μg g-1 in males from South Georgia). Results suggest that females may use egg laying as a mechanism to excrete mercury, with eggs having higher concentrations than the corresponding somatic tissue. Organic mercury makes up a minor percentage of total mercury (15-37%) with the percentage being greater in adults than in juveniles. When compared to euphausiids from other parts of the world, the concentration of mercury in Antarctic krill is within the same range, or higher, highlighting the global distribution of this contaminant. Given the high potential for biomagnification of mercury through food webs, concentrations in Antarctic krill may have deleterious effects on long-lived Antarctic krill predators.
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Affiliation(s)
- José Seco
- Department of Chemistry and CESAM, University of Aveiro, 3810-193, Aveiro, Portugal; Pelagic Ecology Research Group, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK.
| | - José C Xavier
- British Antarctic Survey, NERC, High Cross, Madingley Road, CB30ET, Cambridge, UK; MARE-Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, 3000-456, Coimbra, Portugal
| | - João P Coelho
- Department of Biology and CESAM, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Bárbara Pereira
- Department of Chemistry and CESAM, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Geraint Tarling
- British Antarctic Survey, NERC, High Cross, Madingley Road, CB30ET, Cambridge, UK
| | - Miguel A Pardal
- CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-Université de La Rochelle, 2 Rue Olympe de Gouges, 17000, La Rochelle, France
| | - Gabriele Stowasser
- British Antarctic Survey, NERC, High Cross, Madingley Road, CB30ET, Cambridge, UK
| | - Andrew S Brierley
- Pelagic Ecology Research Group, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK
| | - Maria E Pereira
- Department of Chemistry and CESAM, University of Aveiro, 3810-193, Aveiro, Portugal
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Analysis of air mass back trajectories with present and historical volcanic activity and anthropogenic compounds to infer pollution sources in the South Shetland Islands (Antarctica). ACTA ACUST UNITED AC 2018. [DOI: 10.2478/bgeo-2018-0020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Abstract
This work analyses atmospheric transport of natural and anthropogenic pollution to the South Shetland Islands (SSI), with particular reference to the period September 2015 – August 2017. Based on data from the Global Volcanism Program database and air mass back trajectories calculated using the HySPLIT model, it was found that it is possible that in the analysed period volcanic pollution was supplied via long-range transport from South America, and from the South Sandwich Islands. Air masses flowed in over the South Shetland Islands from the South America region relatively frequently – 226 times during the study period, which suggests the additional possibility of anthropogenic pollution being supplied by this means. In certain cases the trajectories also indicated the possibility of atmospheric transport from the New Zealand region, and even from the south-eastern coast of Australia. The analysis of the obtained results is compared against the background of research by other authors. This is done to indicate that research into the origin of chemical compounds in the Antarctic environment should take into account the possible influx of pollutants from remote areas during the sampling period, as well as the possible reemission of compounds accumulated in snow and ice.
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8
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Evidence of an active volcanic heat source beneath the Pine Island Glacier. Nat Commun 2018; 9:2431. [PMID: 29934507 PMCID: PMC6014989 DOI: 10.1038/s41467-018-04421-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 04/16/2018] [Indexed: 12/05/2022] Open
Abstract
Tectonic landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~ 2500 ± 1700 MW, which is ca. half as large as the active Grimsvötn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS. The West Antarctic Ice Sheet sits atop an extensional rift system with volcano-like features, yet we do not know if any of these volcanoes are active, because identifying subglacial volcanism remains a challenge. Here, the authors find evidence in helium isotopes that a large volcanic heat source is emanating from beneath the fast-melting Pine Island Ice Glacier.
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9
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Licht KJ, Groth T, Townsend JP, Hennessy AJ, Hemming SR, Flood TP, Studinger M. Evidence for Extending Anomalous Miocene Volcanism at the Edge of the East Antarctic Craton. GEOPHYSICAL RESEARCH LETTERS 2018; 45:3009-3016. [PMID: 33122867 PMCID: PMC7592695 DOI: 10.1002/2018gl077237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/18/2018] [Indexed: 06/11/2023]
Abstract
Using field observations followed by petrological, geochemical, geochronological, and geophysical data we infer the presence of a previously unknown Miocene subglacial volcanic center ~230 km from the South Pole. Evidence of volcanism is from boulders of olivine-bearing amygdaloidal/vesicular basalt and hyaloclastite deposited in a moraine in the southern Transantarctic Mountains. 40Ar/39Ar ages from five specimens plus U-Pb ages of detrital zircon from glacial till indicate igneous activity 25-17 Ma. The likely source of the volcanism is a circular -735 nT magnetic anomaly 60 km upflow from the sampling site. Subaqueous textures of the volcanics indicate eruption beneath ice or into water at the margin of an ice mass during the early Miocene. These rocks record the southernmost Cenozoic volcanism in Antarctica and expand the known extent of the oldest lavas associated with West Antarctic rift system. They may be an expression of lithospheric foundering beneath the southern Transantarctic Mountains.
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Affiliation(s)
- K J Licht
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - T Groth
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - J P Townsend
- HEDP Theory Department, Sandia National Laboratories, Albuquerque, NM, USA
| | - A J Hennessy
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - S R Hemming
- Department of Earth and Environmental Sciences, Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, USA
| | - T P Flood
- Geology Department, St. Norbert College, DePere, WI, USA
| | - M Studinger
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
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Contrafatto D, Fasone R, Ferro A, Larocca G, Laudani G, Rapisarda S, Scuderi L, Zuccarello L, Privitera E, Cannata A. Design of a seismo-acoustic station for Antarctica. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:044502. [PMID: 29716353 DOI: 10.1063/1.5023481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In recent years, seismological studies in Antarctica have contributed plenty of new knowledge in many fields of earth science. Moreover, acoustic investigations are now also considered a powerful tool that provides insights for many different objectives, such as analyses of regional climate-related changes and studies of volcanic degassing and explosive activities. However, installation and maintenance of scientific instrumentation in Antarctica can be really challenging. Indeed, the instruments have to face the most extreme climate on the planet. They must be tolerant of very low temperatures and robust enough to survive strong winds. Moreover, one of the most critical tasks is powering a remote system year-round at polar latitudes. In this work, we present a novel seismo-acoustic station designed to work reliably in polar regions. To enable year-round seismo-acoustic data collection in such a remote, extreme environment, a hybrid powering system is used, integrating solar panels, a wind generator, and batteries. A power management system was specifically developed to either charge the battery bank or divert energy surplus to warm the enclosure or release the excess energy to the outside environment. Finally, due to the prohibitive environmental conditions at most Antarctic installation sites, the station was designed to be deployed quickly.
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Affiliation(s)
- Danilo Contrafatto
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | | | - Angelo Ferro
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Graziano Larocca
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Giuseppe Laudani
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Salvatore Rapisarda
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Luciano Scuderi
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Luciano Zuccarello
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Eugenio Privitera
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
| | - Andrea Cannata
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy
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