submarine volcano
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2021 ◽  
Author(s):  
Kosuke Heki ◽  
Tatsuya Fujimoto

Abstract Continuous Plinian eruptions of volcanoes often excite atmospheric resonant oscillations with several distinct periods of a few minutes. We detected such harmonic oscillations excited by the 2021 August eruption of the Fukutoku-Okanoba volcano, a submarine volcano in the Izu-Bonin arc, in ionospheric total electron content (TEC) observed from global navigation satellite system (GNSS) stations deployed on three nearby islands, Chichijima, Hahajima, and Iwojima. Continuous records with the geostationary satellite of Quasi-Zenith Satellite System (QZSS) presented four frequency peaks of such atmospheric modes. The harmonic TEC oscillations, started at ~5:16 UT, exhibited an unprecedented large amplitude but decayed in a few hours.


2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Noriko Tada ◽  
Haruka Nishikawa ◽  
Hiroshi Ichihara ◽  
Hiromi Kayama Watanabe ◽  
Tatsu Kuwatani

AbstractOcean bottom electromagnetometers (OBEMs) installed on the seafloor around Nishinoshima Island (Bonin Islands) were missing after a December volcanic eruption. In February 2021, one was found on a beach on Iriomote Island (Ryukyu Islands), implying that it drifted westward for 1700 km. The reason(s) for the disappearance of the OBEMs and the path followed by the recovered OBEM while drifting are important information for future ocean bottom observations and seafloor volcanology in general. We conducted particle drifting simulations with and without horizonal eddy diffusion to estimate the possible drift path and duration of the recovered OBEM. Our simulations show that particles arriving at Iriomote Island have a 7–10% probability of having been transported from Nishinoshima; thus, such transport is not a rare occurrence. Transport durations in our simulations varied widely between 140 and 602 days depending on the drift paths. More detailed insight into the path and duration of drift of the OBEM will require further comparison between drifting simulations and growth histories of barnacles attached on the OBEM. A similar drift duration and path was reported for pumices that erupted from Fukutoku-Oka-no-Ba submarine volcano (southern Bonin Islands) during 18–21 January 1986 and arrived in the Ryukyu Islands in late May 1986. Such drifting simulations may prove useful for identifying the sources of drift pumices, and thus otherwise undetectable eruptions. Finally, the Fukutoku-Oka-no-Ba submarine volcano erupted on 13 August 2021, producing abundant pumice rafts that, based on our results, would likely arrive in the Ryukyu Islands. In fact, the beginning of October 2021, they began to arrive in the Ryukyu Islands. Graphical Abstract


2021 ◽  
Author(s):  
Helena Seivane ◽  
Rosa Martín ◽  
Javier Almendros ◽  
William Wilcock ◽  
Dax Soule

2021 ◽  
Vol 83 (11) ◽  
Author(s):  
Samuel J. Mitchell ◽  
Kristen E. Fauria ◽  
Bruce F. Houghton ◽  
Rebecca J. Carey

AbstractSilicic submarine volcanic eruptions can produce large volumes of pumices that may rise buoyantly to the ocean surface and/or sink to the seafloor. For eruptions that release significant volumes of pumice into rafts, the proximal to medial submarine geologic record is thus depleted in large volumes of pumice that would have sedimented closer to source in any subaerial eruption. The 2012 eruption of Havre volcano, a submarine volcano in the Kermadec Arc, presents a unique opportunity to study the partitioning of well-constrained rafted and seafloor pumice. Macro- and microtextural analysis was performed on clasts from the Havre pumice raft and from coeval pumiceous seafloor units around the Havre caldera. The raft and seafloor clasts have indistinguishable macrotextures, componentry, and vesicularity ranges. Microtextural differences are apparent as raft pumices have higher vesicle number densities (109 cm−3 vs. 108 cm−3) and significantly lower pore space connectivity (0.3–0.95 vs. 0.9–1.0) than seafloor pumices. Porosity analysis shows that high vesicularity raft pumices required trapping of gas in the connected porosity to remain afloat, whereas lower vesicularity raft pumices could float just from gas within isolated porosity. Measurements of minimum vesicle throat openings further show that raft pumices have a larger proportion of small vesicle throats than seafloor pumices. Narrow throats increase gas trapping as a result of higher capillary pressures acting over gas–water interfaces between vesicles and lower capillary number inhibiting gas bubble escape. Differences in isolated porosity and pore throat distribution ultimately control whether pumices sink or float and thus whether pumice deposits are preserved or not on the seafloor.


2021 ◽  
Author(s):  
Noriko Tada ◽  
Haruka Nishikawa ◽  
Hiroshi Ichihara ◽  
Hiromi Kayama Watanabe ◽  
Tatsu Kuwatani

Abstract Ocean bottom electromagnetometers (OBEMs) installed on the seafloor around Nishinoshima Island (Bonin Islands) were missing after a December volcanic eruption. In February 2021, one was found on a beach on Iriomote Island (Ryukyu Islands), implying that it drifted westward for 1,700 km. The reason(s) for the disappearance of the OBEMs and the path followed by the recovered OBEM while drifting are important information for future ocean bottom observations and seafloor volcanology in general. We conducted particle drifting simulations with and without horizonal eddy diffusion to estimate the possible drift path and duration of the recovered OBEM. Our simulations show that particles transported from Nishinoshima have a 7-10 % probability of arriving at Iriomote Island, which is thus not a rare occurrence. Transport durations in our simulations varied widely between 140 and 602 days depending on the drift paths. The most likely drift duration in our simulation was 150 – 180 days, with or without eddy diffusion, corresponding to the release from the seafloor of the OBEM between 22 August and 21 September 2020. These dates follow shortly after intensifying eruptions at Nishinoshima, which may have affected the seafloor around the island. A similar drift duration and path was reported for pumices that erupted from Fukutoku-Oka-no-Ba submarine volcano (northern Bonin Islands) during 18-21 January 1986 and arrived in the Ryukyu Islands in late May 1986. Such drifting simulations may prove useful for identifying the sources of drift pumices, and thus otherwise undetectable eruptions. Finally, the Fukutoku-Oka-no-Ba submarine volcano erupted on 13 August 2021, producing abundant pumice rafts that, based on our results, will likely arrive in the Ryukyu Islands in the coming months.


Geosciences ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 374
Author(s):  
Anna Olivé Abelló ◽  
Beatriz Vinha ◽  
Francisco Machín ◽  
Francesco Zerbetto ◽  
Evangelos Bakalis ◽  
...  

Temperature and conductivity fluctuations caused by the hydrothermal emissions released during the degasification stage of the Tagoro submarine volcano (Canary Islands, Spain) have been analysed as a robust proxy for characterising and forecasting the activity of the system. A total of 21 conductivity-temperature-depth time series were gathered on a regular high-resolution grid over the main crater of Tagoro volcano. Temperature and conductivity time series, as manifestations of stochastic events, were investigated in terms of variance and analysed by the Generalised Moments Method (GMM). GMM provides the statistical moments, the structure functions of a process whose shape is an indicator of the underlying stochastic mechanisms and the state of activity of the submarine volcano. Our findings confirm an active hydrothermal process in the submarine volcano with a sub-normal behaviour resulting from anti-persistent fluctuations in time. Its hydrothermal emissions are classified as multifractal processes whose structure functions present a crossover between two time scales. In the shorter time scale, findings point to the multiplicative action of two random processes, hydrothermal vents, which carries those fluctuations driving the circulation over the crater, and the overlying aquatic environment. Given that both temperature and conductivity fluctuations are nonstationary, Tagoro submarine volcano can be characterised as an open system exchanging energy to its surroundings.


2021 ◽  
Author(s):  
Teresa Trua ◽  
Michael P. Marani ◽  
Fabiano Gamberi

Abstract Magmatic reservoirs feed active volcanoes and contribute to Earth’s crust formation. Among the processes operating in these systems, those controlling the early chemical evolution stages of magma are the most difficult to identify. This paper reports the first multi-mineral crystal archive that offers insights on the magmatic dynamics governing the production of basalt to andesite lavas at an oceanic back-arc spreading centre. As a result of these dynamics, a mush-dominated transcrustal system developed in the last 0.7 million years. The micro-scale crystal view identifies physicochemical magmatic environments that pass unobserved using whole-rock chemistry alone. It also supplies an interpretative formation model for plumbing system components, functional for the interpretation of geophysical data.


2021 ◽  
Vol 8 ◽  
Author(s):  
María Luz Fernández de Puelles ◽  
Magdalena Gazá ◽  
Miguel Cabanellas-Reboredo ◽  
Alba González-Vega ◽  
Inma Herrera ◽  
...  

The mesozooplankton community was analyzed over a 6-year period (2013-2018) during the post-eruptive stage of the submarine volcano Tagoro, located south of the island of El Hierro (Canary Archipelago, Spain). Nine cruises from March 2013 to March 2018 were carried out in two different seasons, spring (March-April) and autumn (October). A high-resolution study was carried out across the main cones of Tagoro volcano, as well as a large number of reference stations surrounding El Hierro (unaffected by the volcano). The zooplankton community at the reference stations showed a high similarity with more than 85% of the variation in abundance and composition attributable to seasonal differences. Moreover, our data showed an increase in zooplankton abundance in waters affected by the volcano with a higher presence of non-calanoid copepods and a decline in the diversity of the copepod community, indicating that volcanic inputs have a significant effect on these organisms. Fourteen different zooplankton groups were found but copepods were dominant (79%) with 59 genera and 170 species identified. Despite the high species number, less than 30 presented a larger abundance than 1%. Oncaea and Clausocalanus were the most abundant genera followed by Oithona and Paracalanus (60%). Nine species dominated (>2%): O. media, O. plumifera, and O. setigera among the non-calanoids and M. clausi, P. nanus, P. parvus, C. furcatus, C. arcuicornis, and N. minor among the calanoids. After the initial low abundance of the copepods as a consequence of the eruption, an increase was observed in the last years of the study, where besides the small Paracalanus and Clausocalanus, the Cyclopoids seem to have a good adaptive strategy to the new water conditions. The increase in zooplankton abundance and the decline in the copepod diversity in the area affected by the volcano indicate that important changes in the composition of the zooplankton community have occurred. The effect of the volcanic emissions on the different copepods was more evident in spring when the water was cooler and the mixing layer was deeper. Further and longer research is recommended to monitor the zooplankton community in the natural laboratory of the Tagoro submarine volcano.


2021 ◽  
Vol 8 ◽  
Author(s):  
Sara García-Davis ◽  
Carolina P. Reyes ◽  
Irene Lagunes ◽  
José M. Padrón ◽  
Eugenio Fraile-Nuez ◽  
...  

Marine ecosystems are unique and rich reservoirs of biodiversity with high potential toward improving the quality of human life. The extreme physical–chemical conditions of the oceans have favored marine organisms to produce a great variety of new molecules as a mechanism to ensure their survival, and such compounds possess great biopharmaceutical interest. In particular, marine microbiota represent a promising and inexhaustible source for the development of new drugs. This work presents the taxonomic study of the samples obtained from the underwater volcano Tagoro, which has allowed us to develop a collection of 182 marine bacterial strains. On October 10th, 2011, at La Restinga–El Mar de Las Calmas Marine Reserve, an underwater eruption gave rise to a novel shallow submarine volcano at 1.8 km south of the island of El Hierro, Canary Islands, Spain. During the first 6 months, extreme physical–chemical perturbations, comprising thermal changes, water acidification, deoxygenation, and metal enrichment, resulted in significant alterations of the marine ecosystem. After March 2012, the submarine volcano Tagoro entered an active hydrothermal phase that involved a release of heat, gases, metals, and micronutrients that continues till our present. During 2016, our research team had the opportunity to participate in one of the monitoring oceanographic cruises carried out in the area in order to isolate microorganisms associated with both rock samples and deep-sea invertebrates over Tagoro submarine volcano. In this study, Proteobacteria revealed as the most abundant Phylum with 70.2% among all isolated strains, followed by Firmicutes 19%, Actinobacteria 9.5%, and Bacteroidetes 1.2%. Furthermore, we present the results of the antiproliferative assays of the extracts obtained from small-scale cultures of selected bacterial strains. An analysis of the effects of culture conditions in the antiproliferative activity showed that strains grown in Marine Broth (MB) presented lower GI50 values than those cultured in a modified medium (MM1). This effect is improved when the strains are incubated under agitation conditions. The antiproliferative potential of genera such as Halobacillus, Kangiella, Photobacterium, and Halomonas is revealed. Their biotechnological development provides an excellent starting point to access novel secondary metabolites and enzymes with potential for pharmaceutical and industrial applications.


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