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Paraskevi Nomikou - One of the best experts on this subject based on the ideXlab platform.
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Microbial strains isolated from CO2-venting Kolumbo Submarine Volcano show enhanced co-tolerance to acidity and antibiotics.
Marine Environmental Research, 2019Co-Authors: Manolis Mandalakis, Paraskevi Nomikou, Paraskevi N. Polymenakou, Georgios Kotoulas, Asimenia Gavriilidou, Christos A. Christakis, Matej Medvecký, Stephanos P. Kilias, Maroudio Kentouri, Antonios MagoulasAbstract:As ocean acidification intensifies, there is growing global concern about the impacts that future pH levels are likely to have on marine life and ecosystems. By analogy, a steep decrease of seawater pH with depth is encountered inside the Kolumbo Submarine Volcano (northeast Santorini) as a result of natural CO2 venting, making this system ideal for ocean acidification research. Here, we investigated whether the increase of acidity towards deeper layers of Kolumbo crater had any effect on relevant phenotypic traits of bacterial isolates. A total of 31 Pseudomonas strains were isolated from both surface- (SSL) and deep-seawater layers (DSL), with the latter presenting a significantly higher acid tolerance. In particular, the DSL strains were able to cope with H+ levels that were 18 times higher. Similarly, the DSL isolates exhibited a significantly higher tolerance than SSL strains against six commonly used antibiotics and As(III). More importantly, a significant positive correlation was revealed between antibiotics and acid tolerance across the entire set of SSL and DSL isolates. Our findings imply that Pseudomonas species with higher resilience to antibiotics could be favored by the prospect of acidifying oceans. Further studies are required to determine if this feature is universal across marine bacteria and to assess potential ecological impacts.
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Geochemistry of CO2-Rich Gases Venting From Submarine Volcanism: The Case of Kolumbo (Hellenic Volcanic Arc, Greece)
Frontiers Media S.A., 2019Co-Authors: Andrea Luca Rizzo, Paraskevi Nomikou, Antonio Caracausi, Valérie Chavagnac, Paraskevi N. Polymenakou, Manolis Mandalakis, Georgios Kotoulas, Antonios Magoulas, Alain Castillo, Danai LampridouAbstract:Studies of Submarine hydrothermal systems in Mediterranean Sea are limited to the southern Italian volcanism, while are totally missing in the Aegean. Here, we report on the geochemistry of high-temperature fluids (up to 220°C) venting at 500 m b.s.l. from the floor of Kolumbo Submarine Volcano (Hellenic Volcanic Arc, Greece), which is located 7 km northeast of Santorini Island. Despite the recent unrest at Santorini, Kolumbo Submarine Volcano is considered more active due to a higher seismicity. Rizzo et al. (2016) investigated the He-isotope composition of gases collected from seven chimneys and showed that are dominated by CO2 (>97%), with only a small air contamination. Here we provide more-complete chemical data and isotopic compositions of CO2 and CH4, and Hg(0) concentration. We show that the gases emitted from different vents are fractionated by the partial dissolution of CO2 in water. Fractionation is also evident in the C-isotope composition (δ13CCO2), which varies between -0.04 and 1.15‰. We modeled this process to reconstruct the chemistry and δ13CCO2 of intact magmatic gases before fractionation. We argue that the CO2 prior to CO2 dissolution in water had δ13C ∼-0.4‰ and CO2/3He ∼1 × 1010. This model reveals that the gases emitted from Kolumbo originate from a homogeneous mantle contaminated with CO2, probably due to decarbonation of subducting limestone, which is similar to other Mediterranean arc Volcanoes (e.g., Stromboli, Italy). The isotopic signature of CH4 (δ13C ∼-18‰ and δD ∼-117‰) is within a range of values typically observed for hydrothermal gases (e.g., Panarea and Campi Flegrei, Italy), which is suggestive of mixing between thermogenic and abiotic CH4. We report that the concentrations of Hg(0) in Kolumbo fluids are particularly high (∼61 to 1300 ng m-3) when compared to land-based fumaroles located on Santorini and worldwide aerial volcanic emissions. This finding may represent further evidence for the high level of magmatic activity at Kolumbo. Based on the geo-indicators of temperature and pressure, we calculate that the magmatic gases equilibrate within the Kolumbo hydrothermal system at about 270°C and at a depth of ∼1 km b.s.l
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Temperature and Conductivity as Indicators of the Morphology and Activity of a Submarine Volcano: Avyssos (Nisyros) in the South Aegean Sea, Greece
Geosciences, 2018Co-Authors: Evangelos Bakalis, Theo J. Mertzimekis, Paraskevi Nomikou, Francesco ZerbettoAbstract:The morphology and the activity of a Submarine caldera, Avyssos, at the northern part of Nisyros Volcano in the South Aegean Sea (Greece), has been studied by means of remotely-operated underwater vehicle dives. The recorded time series of temperature and conductivity over the Submarine Volcano have been analyzed in terms of the generalized moments method. The findings of the mathematical analysis shed light on the volcanic activity, but also on the morphology (shape) of the Submarine Volcano. The conductivity time series indicates that the Volcano is at rest, in agreement with other types of observations. On the other hand, temperature fluctuations, which in general describe a multifractal process, show that the Submarine caldera operates as an open system that interacts with its surroundings. This type of analysis can be used as an indicator for the state of activity and the morphological structure (closed or open system) of a Submarine Volcano.
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Breathing modes of Kolumbo Submarine Volcano (Santorini, Greece).
Scientific Reports, 2017Co-Authors: Evangelos Bakalis, Theo J. Mertzimekis, Paraskevi Nomikou, Francesco ZerbettoAbstract:Submarine Volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo’s hydrothermal vent system. The respective time series have been analyzed in terms of non–equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non–conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.
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A distinct source and differentiation history for Kolumbo Submarine Volcano, Santorini volcanic field, Aegean arc
Geochemistry Geophysics Geosystems, 2016Co-Authors: Martijn Klaver, Paraskevi Nomikou, Steven Carey, Ingrid Smet, Athanasios Godelitsas, Pieter Z. VroonAbstract:This study reports the first detailed geochemical characterization of Kolumbo Submarine Volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (
William W Chadwick - One of the best experts on this subject based on the ideXlab platform.
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Recent Eruptions Between 2012 and 2018 Discovered at West Mata Submarine Volcano (NE Lau Basin, SW Pacific) and Characterized by New Ship, AUV, and ROV Data
Frontiers in Marine Science, 2019Co-Authors: William W Chadwick, Susan G. Merle, Kenneth H. Rubin, Andra M. Bobbitt, Tom Kwasnitschka, R. W. EmbleyAbstract:West Mata is a Submarine Volcano located in the SW Pacific Ocean between Fiji and Samoa in the NE Lau Basin. West Mata was discovered to be actively erupting at its summit in September 2008 and May 2009. Water-column chemistry and hydrophone data suggest it was probably continuously active until early 2011. Subsequent repeated bathymetric surveys of West Mata have shown that it changed to a style of frequent but intermittent eruptions away from the summit since then. We present new data from ship-based bathymetric surveys, high-resolution bathymetry from an autonomous underwater vehicle, and observations from remotely operated vehicle dives that document four additional eruptions between 2012-2018. Three of those eruptions occurred between September 2012 and March 2016; one near the summit on the upper ENE rift, a second on the NE flank away from any rift zone, and a third at the NE base of the Volcano. The latter intruded a sill into a basin with thick sediments, uplifted them, and then extruded lava onto the seafloor around them. The most recent of the four eruptions occurred between March 2016 and November 2017 along the middle ENE rift zone and produced pillow lava flows with a shingled morphology and tephra as well as clastic debris that mantled the SE slope. ROV dive observations show that the shallower recent eruptions at West Mata include a substantial pyroclastic component, based on thick (>1m) tephra deposits near eruptive vents. The deepest eruption sites lack these near-vent tephra deposits, suggesting that pyroclastic activity is minimal below ~2500 mbsl. The multibeam sonar re-surveys constrain the timing, thickness, area, morphology, and volume of the new eruptions. The cumulative erupted volume since 1996 suggests that eruptions at West Mata are volume-predictable with an average eruption rate of 7.8 x 106 m3/yr. This relatively low magma supply rate and the high frequency of eruptions (every 1-2 years) suggests that the magma reservoir at West Mata is relatively small. With its frequent activity, West Mata continues to be an ideal natural laboratory for the study of Submarine volcanic eruptions.
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Long-term explosive degassing and debris flow activity at West Mata Submarine Volcano
Geophysical Research Letters, 2015Co-Authors: Robert P. Dziak, Susan G. Merle, Edward T. Baker, Sharon L Walker, Delwayne R. Bohnenstiehl, Robert W. Embley, H. Matsumoto, Jacqueline Caplan-auerbach, Tai-kwan Lau, William W ChadwickAbstract:West Mata is a 1200 m deep Submarine Volcano where explosive boninite eruptions were observed in 2009. The acoustic signatures from the Volcano's summit eruptive vents Hades and Prometheus were recorded with an in situ (~25 m range) hydrophone during ROV dives in May 2009 and with local (~5 km range) moored hydrophones between December 2009 and August 2011. The sensors recorded low frequency (1–40 Hz), short duration explosions consistent with magma bubble bursts from Hades, and broadband, 1–5 min duration signals associated with episodes of fragmentation degassing from Prometheus. Long-term eruptive degassing signals, recorded through May 2010, preceded a several month period of declining activity. Degassing episodes were not recorded acoustically after early 2011, although quieter effusive eruption activity may have continued. Synchronous optical measurements of turbidity made between December 2009 and April 2010 indicate that turbidity maxima resulted from occasional south flank slope failures triggered by the collapse of accumulated debris during eruption intervals.
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Imaging of CO2 bubble plumes above an erupting Submarine Volcano, NW Rota‐1, Mariana Arc
Geochemistry Geophysics Geosystems, 2014Co-Authors: William W Chadwick, Joseph A. Resing, Susan G. Merle, Nathaniel J. Buck, J. William Lavelle, Vicki Lynn FerriniAbstract:NW Rota-1 is a Submarine Volcano in the Mariana volcanic arc located ∼100 km north of Guam. Underwater explosive eruptions driven by magmatic gases were first witnessed there in 2004 and continued until at least 2010. During a March 2010 expedition, visual observations documented continuous but variable eruptive activity at multiple vents at ∼560 m depth. Some vents released CO2 bubbles passively and continuously, while others released CO2 during stronger but intermittent explosive bursts. Plumes of CO2 bubbles in the water column over the Volcano were imaged by an EM122 (12 kHz) multibeam sonar system. Throughout the 2010 expedition numerous passes were made over the eruptive vents with the ship to document the temporal variability of the bubble plumes and relate them to the eruptive activity on the seafloor, as recorded by an in situ hydrophone and visual observations. Analysis of the EM122 midwater data set shows: (1) bubble plumes were present on every pass over the summit and they rose 200–400 m above the vents but dissolved before they reached the ocean surface, (2) bubble plume deflection direction and distance correlate well with ocean current direction and velocity determined from the ship's acoustic doppler current profiler, (3) bubble plume heights and volumes were variable over time and correlate with eruptive intensity as measured by the in situ hydrophone. This study shows that midwater multibeam sonar data can be used to characterize the level of eruptive activity and its temporal variability at a shallow Submarine Volcano with robust CO2 output.
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imaging of co2 bubble plumes above an erupting Submarine Volcano nw rota 1 mariana arc
Geochemistry Geophysics Geosystems, 2014Co-Authors: William W Chadwick, Joseph A. Resing, Susan G. Merle, Nathaniel J. Buck, William J Lavelle, Vicki Lynn FerriniAbstract:NW Rota-1 is a Submarine Volcano in the Mariana volcanic arc located ∼100 km north of Guam. Underwater explosive eruptions driven by magmatic gases were first witnessed there in 2004 and continued until at least 2010. During a March 2010 expedition, visual observations documented continuous but variable eruptive activity at multiple vents at ∼560 m depth. Some vents released CO2 bubbles passively and continuously, while others released CO2 during stronger but intermittent explosive bursts. Plumes of CO2 bubbles in the water column over the Volcano were imaged by an EM122 (12 kHz) multibeam sonar system. Throughout the 2010 expedition numerous passes were made over the eruptive vents with the ship to document the temporal variability of the bubble plumes and relate them to the eruptive activity on the seafloor, as recorded by an in situ hydrophone and visual observations. Analysis of the EM122 midwater data set shows: (1) bubble plumes were present on every pass over the summit and they rose 200–400 m above the vents but dissolved before they reached the ocean surface, (2) bubble plume deflection direction and distance correlate well with ocean current direction and velocity determined from the ship's acoustic doppler current profiler, (3) bubble plume heights and volumes were variable over time and correlate with eruptive intensity as measured by the in situ hydrophone. This study shows that midwater multibeam sonar data can be used to characterize the level of eruptive activity and its temporal variability at a shallow Submarine Volcano with robust CO2 output.
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Submarine landslide triggered by volcanic eruption recorded by in situ hydrophone
Geology, 2011Co-Authors: William W Chadwick, J. H. Haxel, Robert P. Dziak, Robert W. Embley, H. MatsumotoAbstract:NW Rota-1 is a Submarine Volcano in the Mariana volcanic arc that is notable as the site where underwater explosive eruptions were first witnessed in A.D. 2004. After years of continuous low-level eruptive activity, a major landslide occurred at NW Rota-1 in August 2009, triggered by an unusually large eruption that produced 10 times the acoustic energy of the background level of activity. An anomalous earthquake swarm preceded the eruption, suggesting that the sequence started with a magmatic intrusion and associated faulting beneath the Volcano. We quantify the size and extent of the landslide using bathymetric resurveys and interpret the timing of events using data from an in situ hydrophone. This is the first instrumental documentation of an earthquake-eruption-landslide sequence at a Submarine Volcano, and illustrates the close interaction between magmatic activity and mass wasting events in the growth of undersea arc Volcanoes.
Steven Carey - One of the best experts on this subject based on the ideXlab platform.
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Flank instability assessment at Kick-’em-Jenny Submarine Volcano (Grenada, Lesser Antilles): a multidisciplinary approach using experiments and modeling
Bulletin of Volcanology, 2016Co-Authors: F. J-y. Dondin, Michael J. Heap, Richard Robertson, J-f. M. Dorville, Steven CareyAbstract:Kick-’em-Jenny (KeJ)—located ca. 8 km north of the island of Grenada—is the only active Submarine Volcano of the Lesser Antilles Volcanic Arc. Previous investigations of KeJ revealed that it lies within a collapse scar inherited from a past flank instability episode. To assess the likelihood of future collapse, we employ here a combined laboratory and modeling approach. Lavas collected using a remotely operated vehicle (ROV) provided samples to perform the first rock physical property measurements for the materials comprising the KeJ edifice. Uniaxial and triaxial deformation experiments showed that the dominant failure mode within the edifice host rock is brittle. Edifice fractures (such as those at Champagne Vent) will therefore assist the outgassing of the nearby magma-filled conduit, favoring effusive behavior. These laboratory data were then used as input parameters in models of slope stability. First, relative slope stability analysis revealed that the SW to N sector of the Volcano displays a deficit of mass/volume with respect to a Volcanoid (ideal 3D surface). Slope stability analysis using a limit equilibrium method (LEM) showed that KeJ is currently stable, since all values of stability factor or factor of safety (Fs) are greater than unity. The lowest values of Fs were found for the SW-NW sector of the Volcano (the sector displaying a mass/volume deficit). Although currently stable, KeJ may become unstable in the future. Instability (severe reductions in Fs) could result, for example, from overpressurization due to the growth of a cryptodome. Our modeling has shown that instability-induced flank collapse will most likely initiate from the SW-NW sector of KeJ, therefore mobilizing a volume of at least ca. 0.7 km3. The mobilization of ca. 0.7 km3 of material is certainly capable of generating a tsunami that poses a significant hazard to the southern islands of the West Indies.
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Exploring the “Sharkcano”: Biogeochemical observations of the Kavachi Submarine Volcano (Solomon Islands)
Oceanography, 2016Co-Authors: Brennan T. Phillips, Matthew Dunbabin, Brad Henning, Corey Howell, Alex Deciccio, Ashton Flinders, Katherine A. Kelley, Jarrod Scott, Simon Albert, Steven CareyAbstract:An expedition to the Kavachi Submarine Volcano (Solomon Islands) in January 2015 was serendipitously timed with a rare lull in volcanic activity that permitted access to the inside of Kavachi’s active crater and its flanks. The isolated location of Kavachi and its explosive behavior normally restrict scientific access to the Volcano’s summit, limiting previous observational efforts to surface imagery and peripheral water-column data. This article presents medium-resolution bathymetry of the main peak along with benthic imagery, biological observations of multiple trophic levels living inside the active crater, petrological and geochemical analysis of samples from the crater rim, measurements of water temperature and gas flux over the summit, and descriptions of the hydrothermal plume structure. A second peak was identified to the southwest of the main summit and displayed evidence of diffuse-flow venting. Microbial samples collected from the summit indicate chemosynthetic populations dominated by sulfur-reducing e-proteobacteria. Populations of gelatinous animals, small fish, and sharks were observed inside the active crater, raising new questions about the ecology of active Submarine Volcanoes and the extreme environments in which large marine animals can exist.
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A distinct source and differentiation history for Kolumbo Submarine Volcano, Santorini volcanic field, Aegean arc
Geochemistry Geophysics Geosystems, 2016Co-Authors: Martijn Klaver, Paraskevi Nomikou, Steven Carey, Ingrid Smet, Athanasios Godelitsas, Pieter Z. VroonAbstract:This study reports the first detailed geochemical characterization of Kolumbo Submarine Volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (
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a distinct source and differentiation history for kolumbo Submarine Volcano santorini volcanic field aegean arc
Geochemistry Geophysics Geosystems, 2016Co-Authors: Paraskevi Nomikou, Steven Carey, Martijn Klaver, Ingrid Smet, Athanasios Godelitsas, Pieter Z. VroonAbstract:This study reports the first detailed geochemical characterization of Kolumbo Submarine Volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (<18.82) that has not been recognized in the Santorini volcanic products. The strong dissimilarity in both petrogenesis and inferred mantle sources between Kolumbo and Santorini suggests that pronounced source variations can be manifested in arc magmas that are closely associated in space and time within a single volcanic field.
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Hydrothermal venting and mineralization in the crater of Kick'em Jenny Submarine Volcano, Grenada (Lesser Antilles)
Geochemistry Geophysics Geosystems, 2016Co-Authors: Steven Carey, John E. Lupton, Marvin D. Lilley, Rene Olsen, Katerine L.c. Bell, Robert D. Ballard, Frederic Dondin, Chris Roman, Clara Smart, Brad A. SeibelAbstract:Kick'em Jenny is a frequently erupting, shallow Submarine Volcano located 7.5 km off the northern coast of Grenada in the Lesser Antilles subduction zone. Focused and diffuse hydrothermal venting is taking place mainly within a small (∼70 × 110 m) depression within the 300 m diameter crater of the Volcano at depths of about 265 m. Much of the crater is blanketed with a layer of fine-grained tephra that has undergone hydrothermal alteration. Clear fluids and gas are being discharged near the center of the depression from mound-like vents at a maximum temperature of 180°C. The gas consists of 93–96% CO2 with trace amounts of methane and hydrogen. Gas flux measurements of individual bubble streams range from 10 to 100 kg of CO2 per day. Diffuse venting with temperatures 5–35°C above ambient occurs throughout the depression and over large areas of the main crater. These zones are colonized by reddish-yellow bacteria with the production of Fe-oxyhydroxides as surface coatings, fragile spires up to several meters in height, and elongated mounds up to tens of centimeters thick. A high-resolution photomosaic of the inner crater depression shows fluid flow patterns descending the sides of the depression toward the crater floor. We suggest that the negatively buoyant fluid flow is the result of phase separation of hydrothermal fluids at Kick'em Jenny generating a dense saline component that does not rise despite its elevated temperature.
Susan G. Merle - One of the best experts on this subject based on the ideXlab platform.
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Recent Eruptions Between 2012 and 2018 Discovered at West Mata Submarine Volcano (NE Lau Basin, SW Pacific) and Characterized by New Ship, AUV, and ROV Data
Frontiers in Marine Science, 2019Co-Authors: William W Chadwick, Susan G. Merle, Kenneth H. Rubin, Andra M. Bobbitt, Tom Kwasnitschka, R. W. EmbleyAbstract:West Mata is a Submarine Volcano located in the SW Pacific Ocean between Fiji and Samoa in the NE Lau Basin. West Mata was discovered to be actively erupting at its summit in September 2008 and May 2009. Water-column chemistry and hydrophone data suggest it was probably continuously active until early 2011. Subsequent repeated bathymetric surveys of West Mata have shown that it changed to a style of frequent but intermittent eruptions away from the summit since then. We present new data from ship-based bathymetric surveys, high-resolution bathymetry from an autonomous underwater vehicle, and observations from remotely operated vehicle dives that document four additional eruptions between 2012-2018. Three of those eruptions occurred between September 2012 and March 2016; one near the summit on the upper ENE rift, a second on the NE flank away from any rift zone, and a third at the NE base of the Volcano. The latter intruded a sill into a basin with thick sediments, uplifted them, and then extruded lava onto the seafloor around them. The most recent of the four eruptions occurred between March 2016 and November 2017 along the middle ENE rift zone and produced pillow lava flows with a shingled morphology and tephra as well as clastic debris that mantled the SE slope. ROV dive observations show that the shallower recent eruptions at West Mata include a substantial pyroclastic component, based on thick (>1m) tephra deposits near eruptive vents. The deepest eruption sites lack these near-vent tephra deposits, suggesting that pyroclastic activity is minimal below ~2500 mbsl. The multibeam sonar re-surveys constrain the timing, thickness, area, morphology, and volume of the new eruptions. The cumulative erupted volume since 1996 suggests that eruptions at West Mata are volume-predictable with an average eruption rate of 7.8 x 106 m3/yr. This relatively low magma supply rate and the high frequency of eruptions (every 1-2 years) suggests that the magma reservoir at West Mata is relatively small. With its frequent activity, West Mata continues to be an ideal natural laboratory for the study of Submarine volcanic eruptions.
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Long-term explosive degassing and debris flow activity at West Mata Submarine Volcano
Geophysical Research Letters, 2015Co-Authors: Robert P. Dziak, Susan G. Merle, Edward T. Baker, Sharon L Walker, Delwayne R. Bohnenstiehl, Robert W. Embley, H. Matsumoto, Jacqueline Caplan-auerbach, Tai-kwan Lau, William W ChadwickAbstract:West Mata is a 1200 m deep Submarine Volcano where explosive boninite eruptions were observed in 2009. The acoustic signatures from the Volcano's summit eruptive vents Hades and Prometheus were recorded with an in situ (~25 m range) hydrophone during ROV dives in May 2009 and with local (~5 km range) moored hydrophones between December 2009 and August 2011. The sensors recorded low frequency (1–40 Hz), short duration explosions consistent with magma bubble bursts from Hades, and broadband, 1–5 min duration signals associated with episodes of fragmentation degassing from Prometheus. Long-term eruptive degassing signals, recorded through May 2010, preceded a several month period of declining activity. Degassing episodes were not recorded acoustically after early 2011, although quieter effusive eruption activity may have continued. Synchronous optical measurements of turbidity made between December 2009 and April 2010 indicate that turbidity maxima resulted from occasional south flank slope failures triggered by the collapse of accumulated debris during eruption intervals.
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Imaging of CO2 bubble plumes above an erupting Submarine Volcano, NW Rota‐1, Mariana Arc
Geochemistry Geophysics Geosystems, 2014Co-Authors: William W Chadwick, Joseph A. Resing, Susan G. Merle, Nathaniel J. Buck, J. William Lavelle, Vicki Lynn FerriniAbstract:NW Rota-1 is a Submarine Volcano in the Mariana volcanic arc located ∼100 km north of Guam. Underwater explosive eruptions driven by magmatic gases were first witnessed there in 2004 and continued until at least 2010. During a March 2010 expedition, visual observations documented continuous but variable eruptive activity at multiple vents at ∼560 m depth. Some vents released CO2 bubbles passively and continuously, while others released CO2 during stronger but intermittent explosive bursts. Plumes of CO2 bubbles in the water column over the Volcano were imaged by an EM122 (12 kHz) multibeam sonar system. Throughout the 2010 expedition numerous passes were made over the eruptive vents with the ship to document the temporal variability of the bubble plumes and relate them to the eruptive activity on the seafloor, as recorded by an in situ hydrophone and visual observations. Analysis of the EM122 midwater data set shows: (1) bubble plumes were present on every pass over the summit and they rose 200–400 m above the vents but dissolved before they reached the ocean surface, (2) bubble plume deflection direction and distance correlate well with ocean current direction and velocity determined from the ship's acoustic doppler current profiler, (3) bubble plume heights and volumes were variable over time and correlate with eruptive intensity as measured by the in situ hydrophone. This study shows that midwater multibeam sonar data can be used to characterize the level of eruptive activity and its temporal variability at a shallow Submarine Volcano with robust CO2 output.
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imaging of co2 bubble plumes above an erupting Submarine Volcano nw rota 1 mariana arc
Geochemistry Geophysics Geosystems, 2014Co-Authors: William W Chadwick, Joseph A. Resing, Susan G. Merle, Nathaniel J. Buck, William J Lavelle, Vicki Lynn FerriniAbstract:NW Rota-1 is a Submarine Volcano in the Mariana volcanic arc located ∼100 km north of Guam. Underwater explosive eruptions driven by magmatic gases were first witnessed there in 2004 and continued until at least 2010. During a March 2010 expedition, visual observations documented continuous but variable eruptive activity at multiple vents at ∼560 m depth. Some vents released CO2 bubbles passively and continuously, while others released CO2 during stronger but intermittent explosive bursts. Plumes of CO2 bubbles in the water column over the Volcano were imaged by an EM122 (12 kHz) multibeam sonar system. Throughout the 2010 expedition numerous passes were made over the eruptive vents with the ship to document the temporal variability of the bubble plumes and relate them to the eruptive activity on the seafloor, as recorded by an in situ hydrophone and visual observations. Analysis of the EM122 midwater data set shows: (1) bubble plumes were present on every pass over the summit and they rose 200–400 m above the vents but dissolved before they reached the ocean surface, (2) bubble plume deflection direction and distance correlate well with ocean current direction and velocity determined from the ship's acoustic doppler current profiler, (3) bubble plume heights and volumes were variable over time and correlate with eruptive intensity as measured by the in situ hydrophone. This study shows that midwater multibeam sonar data can be used to characterize the level of eruptive activity and its temporal variability at a shallow Submarine Volcano with robust CO2 output.
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Eruption‐fed particle plumes and volcaniclastic deposits at a Submarine Volcano: NW Rota‐1, Mariana Arc
Journal of Geophysical Research: Solid Earth, 2008Co-Authors: Sharon L Walker, Geoffrey T Lebon, John E. Lupton, Joseph A. Resing, Edward T. Baker, William W Chadwick, Susan G. MerleAbstract:[1] NW Rota-1 is an active Submarine Volcano in the Mariana Arc with a summit depth of 517 m and an explosively erupting volcanic vent southwest of the summit at a depth of 530–560 m. During a period of ongoing explosive eruptions, particle plumes surrounded the Volcano and at least 3.3 × 107 m3 of volcaniclastic material was deposited on the southern flank. Particle plumes over the summit were magmatic-hydrothermal in origin characterized by 3He enrichment, hydrothermal precipitates, and low pH values. Plumes at multiple depths below the summit surrounded the Volcano and were composed overwhelmingly of fresh, glassy shards of basalt. Rare anhydrite particles were present, but there was a complete absence of other hydrothermal components in the deep plume samples. These short-lived anhydrite particles indicate the source of the deep plumes is from within or very near the eruptive vent, and the mechanism for transport down the flanks of the Volcano must be far faster than settling of individual particles. The deep plumes most likely originated from sediment gravity flows generated by explosive eruptions or slope failure and landslides of unstable materials that had accumulated near the eruptive vent. Suspended sediments detach from the Volcano slopes at multiple depths and are transported laterally up to tens of kilometers where they contribute to fall-out deposits in distal sediments. These observations link mechanisms for the transport of volcanic ash in the Submarine environment to the types of deposits common in volcaniclastic aprons and fine ash layers in distal sediments.
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A distinct source and differentiation history for Kolumbo Submarine Volcano, Santorini volcanic field, Aegean arc
Geochemistry Geophysics Geosystems, 2016Co-Authors: Martijn Klaver, Paraskevi Nomikou, Steven Carey, Ingrid Smet, Athanasios Godelitsas, Pieter Z. VroonAbstract:This study reports the first detailed geochemical characterization of Kolumbo Submarine Volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (
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a distinct source and differentiation history for kolumbo Submarine Volcano santorini volcanic field aegean arc
Geochemistry Geophysics Geosystems, 2016Co-Authors: Paraskevi Nomikou, Steven Carey, Martijn Klaver, Ingrid Smet, Athanasios Godelitsas, Pieter Z. VroonAbstract:This study reports the first detailed geochemical characterization of Kolumbo Submarine Volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (<18.82) that has not been recognized in the Santorini volcanic products. The strong dissimilarity in both petrogenesis and inferred mantle sources between Kolumbo and Santorini suggests that pronounced source variations can be manifested in arc magmas that are closely associated in space and time within a single volcanic field.
