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1
Schmidt, Anja, et Benjamin A. Black. « Reckoning with the Rocky Relationship Between Eruption Size and Climate Response : Toward a Volcano-Climate Index ». Annual Review of Earth and Planetary Sciences 50, no 1 (31 mai 2022) : 627–61. http://dx.doi.org/10.1146/annurev-earth-080921-052816.
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Volcanic eruptions impact climate, subtly and profoundly. The size of an eruption is only loosely correlated with the severity of its climate effects, which can include changes in surface temperature, ozone levels, stratospheric dynamics, precipitation, and ocean circulation. We review the processes—in magma chambers, eruption columns, and the oceans, biosphere, and atmosphere—that mediate the climate response to an eruption. A complex relationship between eruption size, style, duration, and the subsequent severity of the climate response emerges. We advocate for a new, consistent metric, the Volcano-Climate Index, to categorize climate response to eruptions independent of eruption properties and spanning the full range of volcanic activity, from brief explosive eruptions to long-lasting flood basalts. A consistent metric for categorizing the climate response to eruptions that differ in size, style, and duration is critical for establishing the relationshipbetween the severity and the frequency of such responses aiding hazard assessments, and furthering understanding of volcanic impacts on climate on timescales of years to millions of years. ▪ We review the processes driving the rocky relationship between eruption size and climate response and propose a Volcano-Climate Index. ▪ Volcanic eruptions perturb Earth's climate on a range of timescales, with key open questions regarding how processes in the magmatic system, eruption column, and atmosphere shape the climate response to volcanism. ▪ A Volcano-Climate Index will provide information on the volcano-climate severity-frequency distribution, analogous to earthquake hazards. ▪ Understanding of the frequency of specific levels of volcanic climate effects will aid hazard assessments, planning, and mitigation of societal impacts.
2
Tsatsanifos, C., V. Kontogianni et S. Stiros. « Tunneling and other engineering works in volcanic environments : Sousaki and Thessaly ». Bulletin of the Geological Society of Greece 40, no 4 (1 janvier 2007) : 1733. http://dx.doi.org/10.12681/bgsg.17102.
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This study is inspired by the impacts on a tunnel of the Sousaki volcano, in the vicinity of Corinth and examines possible impacts of the Quaternary volcanism on major engineering works in Thessaly. The Sousaki volcano, at the NW edge of the Aegean Volcanic Arc has been associated with important volcanic activity in the past, but its current activity is confined to géothermie phenomena. A tunnel for the new Athens-Corinth High Speed Rail was excavated through the solfatara of the volcano, an area characterized by numerous faults and physical cavities. High temperatures and geothermal gases released in the underground opening through the faults caused disturbance to the tunnel construction, need for supplementary investigations and adoption of special measures to maintain tunnel stability. Experience from the tunnel at Sousaki indicates that similar risks may be faced in future major engineering works in other regions of Greece. Such an example is the area of Microthives and Achillio, Magnesia, Thessaly. Tunnels for the new highway and railway networks constructed or planned through at least two volcanic domes and other main engineering works may also face volcano-associated effects. Optimization of the network routes in combination with special construction techniques and safety measures need to be followed for minimization of such volcanic risks.
3
Ibáñez, Jesús M., Ignacio Castro-Melgar, Ornella Cocina, Luciano Zuccarello, Stefano Branca, Edoardo Del Pezzo et Janire Prudencio. « First 2-D intrinsic and scattering attenuation images of Mt Etna volcano and surrounding region from active seismic data ». Geophysical Journal International 220, no 1 (7 octobre 2019) : 267–77. http://dx.doi.org/10.1093/gji/ggz450.
Texte intégralRésumé :
SUMMARY We present 2-D attenuation images of the Mt Etna volcanic region on the basis of separation of intrinsic and scattering effects. The analysis presented here exploits a large active seismic database that fully covers the area under study. We observe that scattering effects dominate over intrinsic attenuation, suggesting that the region is very heterogeneous. Comparison with analyses conducted at other volcanoes reveals that the Mt Etna region is characterized by high intrinsic attenuation, resulting from the presence of large volcanoclastic deposits at shallow depth. The 2-D distributions of intrinsic and scattering anomalies show the presence of regions characterized by high and low attenuation effects, corresponding to several tectonic and volcanic features. In particular, we identify a high attenuation region in the SW sector of the Mt Etna volcanic complex, which is correlated with high seismicity rates and volcanism. This work supports the hypothesis of a link between the dynamics of the SW flank and the recharge of the volcano in the last decades, occurring under the summit crater and, secondarily, the upper South rift zone.
4
Bredemeyer, Stefan, Franz-Georg Ulmer, Thor Hansteen et Thomas Walter. « Radar Path Delay Effects in Volcanic Gas Plumes : The Case of Láscar Volcano, Northern Chile ». Remote Sensing 10, no 10 (21 septembre 2018) : 1514. http://dx.doi.org/10.3390/rs10101514.
Texte intégralRésumé :
Modern volcano monitoring commonly involves Interferometric Synthetic Aperture Radar (InSAR) measurements to identify ground motions caused by volcanic activity. However, InSAR is largely affected by changes in atmospheric refractivity, in particular by changes which can be attributed to the distribution of water (H2O) vapor in the atmospheric column. Gas emissions from continuously degassing volcanoes contain abundant water vapor and thus produce variations in the atmospheric water vapor content above and downwind of the volcano, which are notably well captured by short-wavelength X-band SAR systems. These variations may in turn cause differential phase errors in volcano deformation estimates due to excess radar path delay effects within the volcanic gas plume. Inversely, if these radar path delay effects are better understood, they may be even used for monitoring degassing activity, by means of the precipitable water vapor (PWV) content in the plume at the time of SAR acquisitions, which may provide essential information on gas plume dispersion and the state of volcanic and hydrothermal activity. In this work we investigate the radar path delays that were generated by water vapor contained in the volcanic gas plume of the persistently degassing Láscar volcano, which is located in the dry Atacama Desert of Northern Chile. We estimate water vapor contents based on sulfur dioxide (SO2) emission measurements from a scanning UV spectrometer (Mini-DOAS) station installed at Láscar volcano, which were scaled by H2O/SO2 molar mixing ratios obtained during a multi-component Gas Analyzer System (Multi-GAS) survey on the crater rim of the volcano. To calculate the water vapor content in the downwind portion of the plume, where an increase of water vapor is expected, we further applied a correction involving estimation of potential evaporation rates of water droplets governed by turbulent mixing of the condensed volcanic plume with the dry atmosphere. Based on these estimates we obtain daily average PWV contents inside the volcanic gas plume of 0.2–2.5 mm equivalent water column, which translates to a slant wet delay (SWD) in DInSAR data of 1.6–20 mm. We used these estimates in combination with our high resolution TerraSAR-X DInSAR observations at Láscar volcano, in order to demonstrate the occurrence of repeated atmospheric delay patterns that were generated by volcanic gas emissions. We show that gas plume related refractivity changes are significant and detectable in DInSAR measurements. Implications are two-fold: X-band satellite radar observations also contain information on the degassing state of a volcano, while deformation signals need to be interpreted with care, which has relevance for volcano observations at Láscar and for other sites worldwide.
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Toman, Ivan, David Brčić et Serdjo Kos. « Contribution to the Research of the Effects of Etna Volcano Activity on the Features of the Ionospheric Total Electron Content Behaviour ». Remote Sensing 13, no 5 (6 mars 2021) : 1006. http://dx.doi.org/10.3390/rs13051006.
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This research represents a contribution to the theory on the coupling of the volcanic activity and the ionospheric dynamics, represented by total electron content (TEC) patterns and their behaviour. The ionospheric response to the activity of the Etna volcano has been analysed using global navigation satellite system (GNSS)-derived TEC values, employing data from International GNSS Service (IGS) reference station near the volcano and on two distant IGS locations. Volcanic activity has been modelled using volcanic radiative power (VRP) data obtained by the Middle InfraRed Observation of Volcanic Activity (MIROVA) system. The estimated minimal night TEC values have been averaged over defined index days of the VRP increase. During the analysed period of 19 years, the volcano activity was categorised according to pre-defined criteria. The influence of current space weather and short-term solar activity on TEC near the volcano was systematically minimised. The results showed mean/median TEC increases of approximately +3 standard deviations from the overall mean values, with peak values placed approximately 5 days before the VRP increase and followed by general TEC depletion around the time of the actual volcanic activity increase. Additionally, TEC oscillation pattern was found over the volcano site with a half-period of 6.25 days. The main interpretation of results indicates that the volcanic activity has modified the ionospheric dynamics within the nearby ionospheric region before the actual VRP increase, and that the residual impact in the volcano’s surrounding area refers to terrestrial endogenous processes and air–earth currents. Those changes can be detected during criteria predefined in the research: during quiet space weather conditions, observing night-time TEC values and within the limits of low short-term solar influence.
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Hu, Yiwei, Boxi Li et Yue Yin. « The Causes of Volcanic Eruptions and How They Affect Our Environment ». Highlights in Science, Engineering and Technology 26 (30 décembre 2022) : 391–96. http://dx.doi.org/10.54097/hset.v26i.4013.
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Volcanic eruptions often have an impact on the environment. In the context of the environmental problem of global warming, a large amount of carbon dioxide released by volcanic eruptions will aggravate the greenhouse effect, which has aroused widespread concern. This article first explains the volcano's cone-shaped structure with several craters, cones, and vents. Although each volcano is unique, most volcanoes can be separated into three major types, the first type is a cinder cone, the second type is a composite volcano, and the third type is a shield volcano. Furthermore, this article interprets the causes of volcanic eruptions by decompression melting, and crustal movement. In addition to this, the environmental impacts of volcanic eruptions from three different angles are explained in the article. The First is the environmental impact of volcanic eruptions at different latitudes. It not only examines the sea surface temperatures' responses to volcanic forcing but also mentions a phenomenon of wind (El Niño de Navidad) caused by volcanic. The second argument is the impact of volcanic eruption on climate. It explains the effects of volcanic dust, Sulphur dioxide, and greenhouse gases, these three main volcanic substances that contribute to environmental cooling, acid rain, and global warming respectively. The final point is the impact of volcanic eruption on the benefits and disadvantages of plant cultivation, hoping this article could raise awareness of volcanoes and global environmental problems and prevent them.
7
Santer, Benjamin, Susan Solomon, David Ridley, John Fyfe, Francisco Beltran, Céline Bonfils, Jeff Painter et Mark Zelinka. « Volcanic effects on climate ». Nature Climate Change 6, no 1 (23 décembre 2015) : 3–4. http://dx.doi.org/10.1038/nclimate2859.
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Mehmood, Maria, Sajid Saleem et Renato Filjar. « Eyjafjallajökull Volcanic Ash 2010 Effects on GPS Positioning Performance in the Adriatic Sea Region ». Atmosphere 13, no 1 (28 décembre 2021) : 47. http://dx.doi.org/10.3390/atmos13010047.
Texte intégralRésumé :
The Eyjafjallajökull volcanic ash crisis in 2010 temporarily suspended European air traffic operations, as the 39-day eruption caused widely dispersed ashes to enter the lower atmosphere. In this paper, we assessed the effects of this event on the ionosphere layer and, consequently, on GPS positioning. We collected and analysed the data from four IGS stations, nearest to the volcano, for the month of April 2010. We recorded Vertical Total Electron Content (VTEC) time series, analysed their dynamics, and compared them with the GPS positioning errors of a commercial-grade, un-aided, single-frequency GPS receiver (simulating the response of a mass-market GPS receiver). The geomagnetic indices during the time period show little geomagnetic disturbance, especially during the volcanic event. Our results show an enhancement in ionosphere error by up to 15% during the volcanic ash event and an enhanced variance in GPS position components errors. This study reveals the potential impact of the charged volcanic ash on single-frequency, unaided GPS positioning accuracy in the Adriatic Sea region and establishes a foundation for studying similar events in future.
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Plummer, C. T., M. A. J. Curran, T. D. van Ommen, S. O. Rasmussen, A. D. Moy, T. R. Vance, H. B. Clausen, B. M. Vinther et P. A. Mayewski. « An independently dated 2000-yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the c. 1450s eruption of Kuwae, Vanuatu ». Climate of the Past Discussions 8, no 3 (2 mai 2012) : 1567–90. http://dx.doi.org/10.5194/cpd-8-1567-2012.
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Abstract. Volcanic eruptions are an important cause of natural climate variability. In order to improve the accuracy of climate models, precise dating and magnitude of the climatic effects of past volcanism are necessary. Here we present a 2000-yr record of Southern Hemisphere volcanism recorded in ice cores from the high accumulation Law Dome site, East Antarctica. The ice cores were analyzed for a suite of chemistry signals and are independently dated via annual layer counting, with 11 ambiguous years by the end of the record. Independently dated records are important to avoid circular dating where volcanic signatures are assigned a date from some external information rather than using the date it is found in the ice core. Forty-five volcanic events have been identified using the sulfate chemistry of the Law Dome record. Comparisons between Law Dome and NGRIP (Greenland) volcanic records suggest Law Dome is the most accurately dated Antarctic volcanic dataset and allows for the records to be synchronized with NGRIP, leading to an improved global volcanic forcing dataset. Volcanic sulfate deposition estimates are important for modeling the climatic response to eruptions. The largest volcanic sulfate events in our record are dated at 1458 CE (Kuwae, Vanuatu), 1257 and 423 CE (unidentified). Using our record we refine the dating of previously known volcanic events and present evidence for two separate eruptions during the period 1450–1460 CE, potentially causing confusion in the assignment of the Kuwae (Vanuatu) eruption to volcanic signatures during this time interval.
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De Ragone, Argelia H. C., Amalia N. F. De Manzano, Ana G. Elias et Marta Z. De Artigas. « Ionospheric effects of volcanic eruptions ». Geofísica Internacional 43, no 2 (1 avril 2004) : 187–92. http://dx.doi.org/10.22201/igeof.00167169p.2004.43.2.169.
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Se han realizado numerosos estudios sobre los efectos ionosféricos de la erupción volcánica del Monte Pinatubo de junio de 1991. Basados en intervalos de 1 minuto de sondaje realizado en estaciones ubicadas al norte del volcán, se han detectado perturbaciones ionosféricas caracterizadas por trenes de onda cuasi-periódicas. Las ondas ionosféricas fueron atribuidas a ondas gravitatorias generadas por la fuerte erupción volcánica del Monte Pinatubo y sus características fueron determinadas. En el presente trabajo se busca detectar perturbaciones ionosféricas causadas por erupciones volcánicas en América, basados en datos horarios de la frecuencia crítica de la capa F2 (foF2) y la altura virtual de la capa F (h’F). El estudio fue realizado para periodos de nivel de actividad magnética tranquila. Ninguna de las erupciones aquí analizadas alcanza la intensidad del Pinatubo. Sin embargo, un decrecimiento de foF2 y de su amplitud de variación y un aumento de h’F en relación con sus valores durante el día previo y el posterior al de la erupción fueron detectados en algunos casos. En otros, la perturbación fue detectada solamente en uno de los parámetros analizados. La ausencia de perturbaciones en registros horarios podría deberse a la falta de coincidencia de los máximos apartamientos de los valores respecto a una situación de normalidad con el momento del registro de los parámetros ionosféricos. La observación de los efectos está directamente relacionada con la intensidad de la erupción.
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RAMPINO, MICHAEL R., RICHARD B. STOTHERS et STEPHEN SELF. « Climatic effects of Volcanic eruptions ». Nature 313, no 6000 (janvier 1985) : 272. http://dx.doi.org/10.1038/313272a0.
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BURKE, KEVIN, et PETER FRANCIS. « Climatic effects of volcanic eruptions ». Nature 314, no 6007 (mars 1985) : 136. http://dx.doi.org/10.1038/314136b0.
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Hansell, A. L. « Respiratory effects of volcanic emissions ». Occupational and Environmental Medicine 60, no 7 (1 juillet 2003) : 529—a—530. http://dx.doi.org/10.1136/oem.60.7.529-a.
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Baxter, Peter J. « Medical effects of volcanic eruptions ». Bulletin of Volcanology 52, no 7 (septembre 1990) : 532–44. http://dx.doi.org/10.1007/bf00301534.
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Chikita, Kazuhisa A., Kazuhiro Amita, Hideo Oyagi et Jun Okada. « Effects of a Volcanic-Fluid Cycle System on Water Chemistry of a Deep Caldera Lake : Lake Tazawa, Akita Prefecture, Japan ». Water 14, no 19 (10 octobre 2022) : 3186. http://dx.doi.org/10.3390/w14193186.
Texte intégralRésumé :
Lake Tazawa, the deepest lake (423.4 m depth at maximum) in Japan underwent drastically changed water quality in 1940, because volcanic water from two active volcanos was then drawn into the lake for power generation and irrigation. Thereby, the pH of lake water decreased from 6.7 to 4.2, which exterminated a land-locked type of sockeye salmon, Oncorhynchus nerkakawamurae (locally called Kunimasu trout). Additionally, the mean residence time of lake water changed from 195 years to 8.9 years by rapidly increasing the outflow for power generation and irrigation. In this study, long-term chemical fluxes controlling lake water chemistry were obtained, and a groundwater water cycle system between the lake and the volcano was explored by estimating hydrological and chemical budgets of the lake. In the chemical budget estimate, two ionic species, SO42− and Cl−, in volcanic fluids were chosen and each mass conservation equation was yielded. The hydrological budget estimate gave us the net groundwater inflow at −1.36 m3/s on average over three periods in 2020–2021, and then the simultaneous equation coupled with the chemical budget equation allowed us to separate into groundwater inflow and outflow at 6.01 m3/s and 7.37 m3/s, averaged over the three periods, respectively. The evaluated groundwater inflow and outflow were compared with those of the other crater or caldera lakes. The linear relationship between the lake volume and the magnitude of groundwater inflow or outflow suggests that the groundwater cycle scale in such a lake increases with the magnitude of the volcanic eruption to have formed the lake.
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Plummer, C. T., M. A. J. Curran, T. D. van Ommen, S. O. Rasmussen, A. D. Moy, T. R. Vance, H. B. Clausen, B. M. Vinther et P. A. Mayewski. « An independently dated 2000-yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the 1450s CE eruption of Kuwae, Vanuatu ». Climate of the Past 8, no 6 (28 novembre 2012) : 1929–40. http://dx.doi.org/10.5194/cp-8-1929-2012.
Texte intégralRésumé :
Abstract. Volcanic eruptions are an important cause of natural climate variability. In order to improve the accuracy of climate models, precise dating and magnitude of the climatic effects of past volcanism are necessary. Here we present a 2000-yr record of Southern Hemisphere volcanism recorded in ice cores from the high accumulation Law Dome site, East Antarctica. The ice cores were analysed for a suite of chemistry signals and are independently dated via annual layer counting, with 11 ambiguous years at 23 BCE, which has presently the lowest error of all published long Antarctic ice cores. Independently dated records are important to avoid circular dating where volcanic signatures are assigned a date from some external information rather than using the date it is found in the ice core. Forty-five volcanic events have been identified using the sulphate chemistry of the Law Dome record. The low dating error and comparison with the NGRIP (North Greenland Ice Core Project) volcanic records (on the GICC05 timescale) suggest Law Dome is the most accurately dated Antarctic volcanic dataset, which will improve the dating of individual volcanic events and potentially allow better correlation between ice core records, leading to improvements in global volcanic forcing datasets. One of the most important volcanic events of the last two millennia is the large 1450s CE event, usually assigned to the eruption of Kuwae, Vanuatu. In this study, we review the evidence surrounding the presently accepted date for this event, and make the case that two separate eruptions have caused confusion in the assignment of this event. Volcanic sulphate deposition estimates are important for modelling the climatic response to eruptions. The largest volcanic sulphate events in our record are dated at 1458 CE (Kuwae?, Vanuatu), 1257 and 422 CE (unidentified).
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Flower, Verity J. B., Thomas Oommen et Simon A. Carn. « Improving global detection of volcanic eruptions using the Ozone Monitoring Instrument (OMI) ». Atmospheric Measurement Techniques 9, no 11 (16 novembre 2016) : 5487–98. http://dx.doi.org/10.5194/amt-9-5487-2016.
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Abstract. Volcanic eruptions pose an ever-present threat to human populations around the globe, but many active volcanoes remain poorly monitored. In regions where ground-based monitoring is present the effects of volcanic eruptions can be moderated through observational alerts to both local populations and service providers, such as air traffic control. However, in regions where volcano monitoring is limited satellite-based remote sensing provides a global data source that can be utilised to provide near-real-time identification of volcanic activity. This paper details a volcanic plume detection method capable of identifying smaller eruptions than is currently feasible, which could potentially be incorporated into automated volcanic alert systems. This method utilises daily, global observations of sulfur dioxide (SO2) by the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite. Following identification and classification of known volcanic eruptions in 2005–2009, the OMI SO2 data, analysed using a logistic regression analysis, permitted the correct classification of volcanic events with an overall accuracy of over 80 %. Accurate volcanic plume identification was possible when lower-tropospheric SO2 loading exceeded ∼ 400 t. The accuracy and minimal user input requirements of the developed procedure provide a basis for incorporation into automated SO2 alert systems.
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Tremiño, Rosa María, Teresa Real-Herraiz, Viviana Letelier et José Marcos Ortega. « Microstructure and Durability Performance of Mortars with Volcanic Powder from Calbuco Volcano (Chile) after 4 Hardening Years ». Materials 14, no 7 (2 avril 2021) : 1751. http://dx.doi.org/10.3390/ma14071751.
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One of the most popular ways to lessen the impact of the cement industry on the environment consists of substituting clinker by additions. The service life required for real construction elements is generally long, so it would be interesting to obtain information about the effects of new additions after a hardening period of several years. Analyzed here are the effects of the incorporation of volcanic ashes, coming from Calbuco volcano’s last eruption (Chile), as clinker replacement, in the durability and pore structure of mortars, after approximately 4 hardening years (1500 days), in comparison with reference specimens without additions. The substitution percentages of clinker by volcanic powder studied were 10% and 20%. The microstructure was characterized with mercury intrusion porosimetry and impedance spectroscopy. In order to evaluate the pozzolanic activity of the volcanic powder after 1500 days, differential thermal analyses were performed. Water absorption after immersion, steady-state diffusion coefficient and length change were also studied. In accordance with the results obtained, the 10% and 20% substitution of clinker by volcanic powder from the Calbuco volcano showed beneficial effects in the mortars after 4 years, especially regarding the microstructure and chloride diffusion, without noticeable influence in their water absorption.
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Eliasson, Jonas, Junichi Yoshitani, Konradin Weber, Nario Yasuda, Masato Iguchi et Andreas Vogel. « Airborne Measurement in the Ash Plume from Mount Sakurajima : Analysis of Gravitational Effects on Dispersion and Fallout ». International Journal of Atmospheric Sciences 2014 (19 octobre 2014) : 1–16. http://dx.doi.org/10.1155/2014/372135.
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Volcanic ash concentrations in the plume from Sakurajima volcano in Japan are observed from airplanes equipped with optical particle counters and GPS tracking devices. The volcano emits several puffs a day. The puffs are also recorded by the Sakurajima Volcanological Observatory. High concentrations are observed in the puffs and fallout driven by vertical air current, called streak fallout. Puffs dispersion is analyzed by the classical diffusion-advection method and a new gravitational dispersion method. The fluid mechanic of the gravitational dispersion, streak fallout, and classical diffusion-advection theory is described in three separate appendices together with methods to find the time gravitational dispersion constant and the diffusion coefficient from satellite photos. The diffusion-advection equation may be used to scale volcanic eruptions so the same eruption plumes can be scaled to constant flux and wind conditions or two eruptions can be scaled to each other. The dispersion analyses show that dispersion of volcanic plumes does not follow either theories completely. It is most likely diffusion in the interface of the plume and the ambient air, together with gravitational flattening of the plumes core. This means larger boundary concentration gradients and smaller diffusion coefficients than state of the art methods can predict.
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Flores-Marquez, E. L., G. Galvez-Coyt et G. Cifuentes-Nava. « Fractal dimension analysis of the magnetic time series associated with the volcanic activity of Popocatépetl ». Nonlinear Processes in Geophysics 19, no 6 (12 décembre 2012) : 693–701. http://dx.doi.org/10.5194/npg-19-693-2012.
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Abstract. Fractal analysis of the total magnetic field (TMF) time series from 1997 to 2003 at Popocatépetl Volcano is performed and compared with the TMF-series of the Teoloyucan Magnetic Observatory, 100 km away. Using Higuchi's fractal dimension method (D). The D changes over time for both series were computed. It was observed, when the time windows used to compute D increase in length, both series show nearly the same behavior. Some criteria of comparison were employed to discriminate the local effects inherent to volcano-magnetism. The simultaneous maximum in D (1.8) of the TMF series at Popocatépetl Volcano and the recovered volcanic activity indicates a scaling relation of the TMF at Popocatépetl Volcano and demonstrates a link between the magnetic field and volcanic activity.
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Letelier, Viviana, José Marcos Ortega, Rosa María Tremiño, Bastián I. Henriquéz-Jara, Ivo Fustos, Teresa Real-Herraiz, Giacomo Moriconi, Miguel Ángel Climent et Isidro Sánchez. « The Use of Volcanic Powder as a Cement Replacement for the Development of Sustainable Mortars ». Applied Sciences 10, no 4 (21 février 2020) : 1460. http://dx.doi.org/10.3390/app10041460.
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Currently, reduction of environmental effects of the cement industry is an issue of global interest and one of the alternatives is to replace clinker with additions such as volcanic powder. The purpose of this work is to study the influence of up to 400 hardening days of volcanic powder, obtained from the last eruption of the Calbuco volcano (Chile), on the pore structure, mechanical performance, and durability-related properties of mortars which incorporate up to 20% volcanic powder as a substitution for clinker. In addition, an evaluation of greenhouse gases emissions was performed in order to quantify the possible environmental benefits of incorporating the volcanic powder in the mortars. The results obtained indicated that mortars with contents of 10% and 20% of volcanic powder had adequate service properties and improved all durability-related properties overall as compared with those noted for ordinary Portland cement. Additionally, the use of up to 20% volcanic powder makes it possible to reduce the CO2 emissions of mortars by almost 20%, demonstrating the advantages of incorporating this addition in mortars.
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Johansson, Daniel J. A., Brian C. O'Neill, Claudia Tebaldi et Olle Häggström. « Reply to 'Volcanic effects on climate' ». Nature Climate Change 6, no 1 (23 décembre 2015) : 4–5. http://dx.doi.org/10.1038/nclimate2861.
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Shakirova, A. A. « SEISMIC EFFECTS AHEAD OF KARYMSKY VOLCANO (KAMCHATKA) EXPLOSIONS IN FEBRUARY 2019 ». BULLETIN OF KAMCHATKA REGIONAL ASSOCIATION «EDUCATIONAL-SCIENTIFIC CENTER». EARTH SCIENCES 1, no 53 (2022) : 12–23. http://dx.doi.org/10.31431/1816-5524-2022-1-53-12-23.
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After a short period of quiescence, in February 2019, Karymsky volcano (Kamchatka Peninsula, Russia) became active. During the month, a large number of moderate explosions were recorded, some of which were preceded with some periodicity by long-period earthquakes with a high degree of similarity of waveforms. The duration of the multiplet events that preceded the explosions ranged from 4 to 70 minutes. The period between earthquakes decreased as the multiplets developed. The amplitude of earthquake records either increased or remained at the same level. The multiplets with higher amplitude of earthquake records preceded the strongest eruptions. The decreasing period between earthquakes is most likely related to the acceleration of magma ascent and an increase in gas pressure in the volcanic channel. If this is true, the absence of long-period earthquakes after the eruption marks a complete release of gas pressure in the volcanic edifice.
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Del Negro, C., F. Greco, R. Napoli et G. Nunnari. « Denoising gravity and geomagnetic signals from Etna volcano (Italy) using multivariate methods ». Nonlinear Processes in Geophysics 15, no 5 (21 octobre 2008) : 735–49. http://dx.doi.org/10.5194/npg-15-735-2008.
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Abstract. Multivariate methods were applied to denoise the gravity and geomagnetic signals continuously recorded by the permanent monitoring networks on the Etna volcano. Gravity and geomagnetic signals observed in volcanic areas are severely influenced by meteorological variables (i.e. pressure, temperature and humidity), whose disturbances can make the detection of volcanic source effects more difficult. For volcano monitoring it is necessary, therefore, to reduce the effects of these perturbations. To date filtering noise is a very complex problem since the spectrum of each noise component has wide intervals of superposition and, some times, traditional filtering techniques provide unsatisfactory results. We propose the application of two different approaches, the adaptive neuro-fuzzy inference system (ANFIS) and the Independent Component Analysis (ICA) to remove noise effects from gravity and geomagnetic time series. Results suggest a good efficiency of the two proposed approaches since they are capable of finding and effectively representing the underlying factors or sources, and allow local features of the signal to be detected.
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Popova, Diana, et Aleksei Sazhenkov. « EFFECTS OF VOLCANIC ASH ON AIRCRAFT GAS TURBINE ENGINES ». Perm National Research Polytechnic University Aerospace Engineering Bulletin, no 70 (2022) : 122–39. http://dx.doi.org/10.15593/2224-9982/2022.70.12.
Texte intégralRésumé :
Volcanic ash clouds emitted into the Earth’s atmosphere by more than a thousand active volcanoes pose an immediate se-rious threat to flight safety, since volcanic ash particles in high concentrations can cause significant damage to aircraft. This article presents the consequences of an aircraft getting into a cloud of volcanic ash (damage to the fuselage and aer-odynamic surfaces of the aircraft, turbojet sustainer engines, antennas, air pressure and temperature receivers, other aircraft sys-tems), and also describes in detail the mechanisms and examples of the impact of volcanic ash on various types aircraft gas tur-bine engines. The global statistics of aircraft hitting volcanic ash clouds from 1935 to 2021 is given. The results of engineering tests of PW F100 bypass gas turbine engines under the influence of volcanic ash in the condi-tions of the scientific and CalspanTechnical Corporation, founded in 1943 in the United States of America, are considered. Also presented are the results of work under the VIPR (Vehicle Integrated Propulsion Research) program of the National Aerospace Agency of the United States of America (NASA) for a comprehensive study of the impact of volcanic ash on the F-117 (PW2040) power plant of the Boeing C-17 Globemaster III military transport aircraft. The results of research by the NASA national agency and the Calspan Corporation are compared with the main data of certification tests of the advanced PD-14 aircraft gas turbine engine developed by JSC «UEC-Aviadvigatel» in the conditions of the closed ground test facility Ts-17T of the FAA «CIAM named after P.I. Baranov» in accordance with the requirements of the European Aviation Safety Agency (EASA).
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García, Rosa Delia, Omaira Elena García, Emilio Cuevas-Agulló, África Barreto, Victoria Eugenia Cachorro, Carlos Marrero, Fernando Almansa, Ramón Ramos et Mario Pó. « Spectral Aerosol Radiative Forcing and Efficiency of the La Palma Volcanic Plume over the Izaña Observatory ». Remote Sensing 15, no 1 (28 décembre 2022) : 173. http://dx.doi.org/10.3390/rs15010173.
Texte intégralRésumé :
On 19 September 2021, a volcanic eruption began on the island of La Palma (Canary Islands, Spain). The eruption has allowed the assessment of an unprecedented multidisciplinary study on the effects of the volcanic plume. This work presents the estimation of the spectral direct radiative forcing (ΔF) and efficiency (ΔFEff) from solar radiation measurements at the Izaña Observatory (IZO) located on the island of Tenerife (∼140 km from the volcano). During the eruption, the IZO was affected by different types of aerosols: volcanic, Saharan mineral dust, and a mixture of volcanic and dust aerosols. Three case studies were identified using ground-based (lidar) data, satellite-based (Sentinel-5P Tropospheric Monitoring Instrument, TROPOMI) data, reanalysis data (Modern-Era Retrospective Analysis for Research and Applications, version 2, MERRA-2), and backward trajectories (Flexible Trajectories, FLEXTRA), and subsequently characterised in terms of optical and micro-physical properties using ground-based sun-photometry measurements. Despite the ΔF of the volcanic aerosols being greater than that of the dust events (associated with the larger aerosol load present), the ΔFEff was found to be lower. The spectral ΔFEff values at 440 nm ranged between −1.9 and −2.6 Wm−2nm−1AOD−1 for the mineral dust and mixed volcanic and dust particles, and between −1.6 and −3.3 Wm−2nm−1AOD−1 for the volcanic aerosols, considering solar zenith angles between 30∘ and 70∘, respectively.
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Graf, H. F., Q. Li et M. A. Giorgetta. « Volcanic effects on climate : revisiting the mechanisms ». Atmospheric Chemistry and Physics Discussions 7, no 2 (22 mars 2007) : 3941–62. http://dx.doi.org/10.5194/acpd-7-3941-2007.
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Abstract. The characteristics of planetary wave energy propagation are being compared based on NCEP reanalysis data from 1958 to 2002 between boreal winters after strong volcanic eruptions, non-volcanic winters and episodes of strong polar vortex lasting at least 30 days. It shows that in the volcanically disturbed winters much more planetary wave energy is produced in the troposphere, passes through the lowermost stratosphere and enters the upper stratosphere than in any other times. This is contradicting earlier interpretations and model simulations. Possibly the observed El Ninos coinciding with the three significant eruptions in the second half of the 20th century contributed to the planetary wave energy. In order to produce the observed robust climate anomaly patterns in the lower troposphere, these planetary waves are suggested to be reflected near the stratopause instead of breaking. While a strong polar vortex is observed after volcanic eruptions in the stratosphere and in the troposphere, specific episodes of strong polar vortex regime exhibit much stronger anomalies and different dynamics. Hence it is suggested that the climate effects of volcanic eruptions are not being explained by the excitation of inherent zonal mean variability modes such as Strong Polar Vortex or Northern Annular Mode, but rather is another mode that possibly reflects upon the North Atlantic Oscillation.
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Graf, H. F., Q. Li et M. A. Giorgetta. « Volcanic effects on climate : revisiting the mechanisms ». Atmospheric Chemistry and Physics 7, no 17 (30 août 2007) : 4503–11. http://dx.doi.org/10.5194/acp-7-4503-2007.
Texte intégralRésumé :
Abstract. The characteristics of planetary wave energy propagation are being compared based on NCEP reanalysis data from 1958 to 2002 between boreal winters after strong volcanic eruptions, non-volcanic winters and episodes of strong polar vortex lasting at least 30 days. It shows that in the volcanically disturbed winters much more planetary wave energy is produced in the troposphere, passes through the lowermost stratosphere and enters the upper stratosphere than in any other times. This is contradicting earlier interpretations and model simulations. Possibly the observed El Ninos coinciding with the three significant eruptions in the second half of the 20th century contributed to the planetary wave energy. In order to produce the observed robust climate anomaly patterns in the lower troposphere, these planetary waves are suggested to be reflected near the stratopause instead of breaking. While a strong polar vortex is observed after volcanic eruptions in the stratosphere and in the troposphere, specific episodes of strong polar vortex regime exhibit much stronger anomalies and different dynamics. Hence it is suggested that the climate effects of volcanic eruptions are not being explained by the excitation of inherent zonal mean variability modes such as Strong Polar Vortex or Northern Annular Mode, but rather is another mode that possibly reflects upon the North Atlantic Oscillation.
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Self, S. « The effects and consequences of very large explosive volcanic eruptions ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 364, no 1845 (28 juin 2006) : 2073–97. http://dx.doi.org/10.1098/rsta.2006.1814.
Texte intégralRésumé :
Every now and again Earth experiences tremendous explosive volcanic eruptions, considerably bigger than the largest witnessed in historic times. Those yielding more than 450 km 3 of magma have been called super-eruptions. The record of such eruptions is incomplete; the most recent known example occurred 26 000 years ago. It is more likely that the Earth will next experience a super-eruption than an impact from a large meteorite greater than 1 km in diameter. Depending on where the volcano is located, the effects will be felt globally or at least by a whole hemisphere. Large areas will be devastated by pyroclastic flow deposits, and the more widely dispersed ash falls will be laid down over continent-sized areas. The most widespread effects will be derived from volcanic gases, sulphur gases being particularly important. This gas is converted into sulphuric acid aerosols in the stratosphere and layers of aerosol can cover the global atmosphere within a few weeks to months. These remain for several years and affect atmospheric circulation causing surface temperature to fall in many regions. Effects include temporary reductions in light levels and severe and unseasonable weather (including cool summers and colder-than-normal winters). Some aspects of the understanding and prediction of super-eruptions are problematic because they are well outside modern experience. Our global society is now very different to that affected by past, modest-sized volcanic activity and is highly vulnerable to catastrophic damage of infrastructure by natural disasters. Major disruption of services that society depends upon can be expected for periods of months to, perhaps, years after the next very large explosive eruption and the cost to global financial markets will be high and sustained.
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Ebmeier, S. K., A. M. Sayer, R. G. Grainger, T. A. Mather et E. Carboni. « Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties ». Atmospheric Chemistry and Physics 14, no 19 (9 octobre 2014) : 10601–18. http://dx.doi.org/10.5194/acp-14-10601-2014.
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Abstract. The impact of volcanic emissions, especially from passive degassing and minor explosions, is a source of uncertainty in estimations of aerosol indirect effects. Observations of the impact of volcanic aerosol on clouds contribute to our understanding of both present-day atmospheric properties and of the pre-industrial baseline necessary to assess aerosol radiative forcing. We present systematic measurements over several years at multiple active and inactive volcanic islands in regions of low present-day aerosol burden. The time-averaged indirect aerosol effects within 200 km downwind of island volcanoes are observed using Moderate Resolution Imaging Spectroradiometer (MODIS, 2002–2013) and Advanced Along-Track Scanning Radiometer (AATSR, 2002–2008) data. Retrievals of aerosol and cloud properties at Kīlauea (Hawai'i), Yasur (Vanuatu) and Piton de la Fournaise (la Réunion) are rotated about the volcanic vent to be parallel to wind direction, so that upwind and downwind retrievals can be compared. The emissions from all three volcanoes – including those from passive degassing, Strombolian activity and minor explosions – lead to measurably increased aerosol optical depth downwind of the active vent. Average cloud droplet effective radius is lower downwind of the volcano in all cases, with the peak difference ranging from 2–8 μm at the different volcanoes in different seasons. Estimations of the difference in Top of Atmosphere upward Short Wave flux upwind and downwind of the active volcanoes from NASA's Clouds and the Earth's Radiant Energy System (CERES) suggest a downwind elevation of between 10 and 45 Wm−2 at distances of 150–400 km from the volcano, with much greater local (< 80 km) effects. Comparison of these observations with cloud properties at isolated islands without degassing or erupting volcanoes suggests that these patterns are not purely orographic in origin. Our observations of unpolluted, isolated marine settings may capture processes similar to those in the pre-industrial marine atmosphere.
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Schäfer, K., W. Thomas, A. Peters, L. Ries, F. Obleitner, J. Schnelle-Kreis, W. Birmili et al. « Influences of the 2010 Eyjafjallajökull volcanic plume on air quality in the northern Alpine region ». Atmospheric Chemistry and Physics Discussions 11, no 3 (16 mars 2011) : 9083–132. http://dx.doi.org/10.5194/acpd-11-9083-2011.
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Abstract. A series of major eruptions of the Eyjafjallajökull volcano in Iceland started on 14 April 2010 and continued until the end of May 2010. The volcanic emissions moved over nearly the whole of Europe and were observed first on 16 April 2010 in Southern Germany with different remote sensing systems from the ground and space. Enhanced PM10 and SO2 concentrations were detected on 17 April at mountain stations (Zugspitze/Schneefernerhaus and Schauinsland) as well as in Innsbruck by in situ measurement devices. On 19 April intensive vertical mixing and advection along with clear sky-conditions facilitated the entrainment of volcanic material down to the ground. The subsequent formation of a stably stratified lower atmosphere with limited mixing near the ground during the evening of 19 April led to an additional enhancement of near-surface particle concentrations. Consequently, on 19 April and 20 April exceedances of the daily threshold value for particulate matter (PM10) were reported at nearly all monitoring stations of the North Alpine foothills as well as at mountain and valley stations in the northern Alps. The chemical analyses of ambient PM10 at monitoring stations of the North Alpine foothills yielded elevated Titanium concentrations on 19/20 April which prove the presence of volcanic plume material. Following this result the PM10 threshold exceedances are also associated with the volcanic plume. The entrainment of the volcanic plume material mainly affected the concentrations of coarse particles (>1 μm) – interpreted as volcanic ash – and ultrafine particles (<100 nm), while the concentrations of accumulation mode aerosol (0.1–1 μm) were not changed significantly. With regard to the occurrence of ultrafine particles, it is concluded that their formation was triggered by high sulphuric acid concentrations which are necessarily generated by the photochemical processes in a plume rich in sulphur dioxide under high solar irradiance. It became evident that during the course of several days, the Eyjafjallajökull volcanic emissions influenced the near-surface atmosphere and thus the ambient air quality. Following knowledge about health effects of air pollutants and volcanic plume compounds, it is assumed that the volcanic plume contributed to the overall exposure of the population and therefore may have had minor effects on the exacerbation of respiratory and cardiovascular symptoms.
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Carlón Allende, Teodoro, José Luis Macías, Manuel E. Mendoza et José Villanueva Díaz. « Evidence of volcanic activity in the growth rings of trees at the Tacaná volcano, Mexico–Guatemala border ». Canadian Journal of Forest Research 50, no 1 (janvier 2020) : 65–72. http://dx.doi.org/10.1139/cjfr-2019-0214.
Texte intégralRésumé :
Volcanic activity can have a significant effect on the growth and survival of trees. The objective of our research was to analyze the effects of the 1855–1856 eruption of the Tacaná volcano and the ashfall from the 1902 eruption of the Santa María volcano, Guatemala, on the radial growth of trees at Tacaná. Dendrochronological sampling was carried out on sites covered by Pinus hartwegii Lindl., and a ring-width chronology was built using 102 increment cores from 75 trees. The ring-width chronology shows two statistically significant suppression events. One of these events occurred from 1857 to 1868 and was potentially caused by the historic eruption of Tacaná (1855–1856). The second suppression event occurred from 1903 to 1908, during which tree growth was affected 1 year after the ashfall caused by the 1902 eruption of Santa María. The growth suppression did not have the same magnitude in all sampled trees and may be related to the thickness of the ash layer deposited around each tree. For the first time, we show that tree growth at Tacaná is reduced by ashfall from volcanic eruptions. Our results may contribute to the evaluation of risks associated with the volcanic activity of the Tacaná volcano.
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Davies, J. A., R. Schroeder et L. J. B. McArthur. « Surface-based observations of volcanic aerosol effects ». Tellus B : Chemical and Physical Meteorology 40, no 2 (mars 1988) : 154–60. http://dx.doi.org/10.3402/tellusb.v40i2.15636.
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Büttner, R., H. Röder et B. Zimanowski. « Electrical effects generated by experimental volcanic explosions ». Applied Physics Letters 70, no 14 (7 avril 1997) : 1903–5. http://dx.doi.org/10.1063/1.118726.
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DAVIES, J. A., R. SCHROEDER et L. J. B. McARTHUR. « Surface-based observations of volcanic aerosol effects ». Tellus B 40B, no 2 (avril 1988) : 154–60. http://dx.doi.org/10.1111/j.1600-0889.1988.tb00219.x.
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Kimura, Katsuaki, Taiji Sakamoto, Miho Miyazaki, Eisuke Uchino, Naoko Kinukawa et Makoto Isashiki. « Effects of volcanic ash on ocular symptoms ». Ophthalmology 112, no 3 (mars 2005) : 478–81. http://dx.doi.org/10.1016/j.ophtha.2004.09.031.
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Durand, Michael, et John Grattan. « Effects of volcanic air pollution on health ». Lancet 357, no 9251 (janvier 2001) : 164. http://dx.doi.org/10.1016/s0140-6736(00)03586-8.
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Williams, Natalia, Diego Añón Suárez, Maria Rieradevall, Andrea Rizzo, Romina Daga, María A. Arribére et Sergio Ribeiro Guevara. « Response of Chironomidae to environmental disturbances in a high mountain lake in Patagonia during the last millennium ». Quaternary Research 92, no 2 (23 avril 2019) : 273–87. http://dx.doi.org/10.1017/qua.2019.5.
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AbstractThrough the last millennium, Patagonia has been affected by changing climate conditions and successive volcanic eruptions. Lake Tonček is a high-altitude lake in the Southern Volcanic Zone in the northern Patagonian Andes. We documented the responses of the subfossil chironomid community to the effects of successive volcanic and different conditions in a sedimentary sequence from this lake comprising the last 900 years. The community composition and structure (abundance, diversity, and richness) and the development of morphological anomalies in the chironomid mouthparts were evaluated throughout the core. Both climatic conditions and volcanism affected the chironomid community differentially. The chironomid community changed following short-term climate change patterns, being affecting not only by temperature changes but also by variations in the regional precipitation regime. Decreases in abundance and diversity were only observed in coarse volcanic layers. In these samples, we recorded a high percentage of damaged chironomid mouthparts caused by mechanical wear, breakage or abrasion, possibly due to the increase of mineral particles. Our results represent important baseline data about the responses of chironomid communities to environmental disturbances in high-altitude lakes over long time frames.
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Kuri, Miwa, et Anawat Suppasri. « Perceptions of Volcanic Hazard-Related Information Relevant to Volcano Tourism Areas in Japan ». Journal of Disaster Research 13, no 6 (1 novembre 2018) : 1082–95. http://dx.doi.org/10.20965/jdr.2018.p1082.
Texte intégralRésumé :
Perceptions of volcanic hazard-related information relevant to volcano tourism areas in Japan were investigated using an Internet questionnaire survey. This study focused on the possibilities of tourism activities as a method of disseminating disaster information not only to residents but also to visitors. We evaluated the effects of educational programs (EP) including recreational activities at geopark, for the purpose of further enhancing information content and establishment of cooperation system. The survey focused on the roles and perspectives of residents, the tourism industry, scientists, and the government in volcanic disaster mitigation, as well as the dissemination of volcanic information with regard to daily activities and the actions to be taken in the event of an emergency. Hazard perceptions tended to be actuate in areas where knowledge dissemination activities were active, but this did not lead to evacuation awareness. Evacuation awareness was correlated with disaster awareness, specifically regarding the degree of interest in a volcano, eruption frequency and style, perceptions of eruption predictability, and trust in information source. Disaster awareness correlated somewhat with eruption style and with the time elapsed science the most recent eruption. Our results showed that the perceptions of residents living near volcanoes depended on eruption frequency, their experience during previous eruptions, and local government assessments of the severity of the volcanic hazard. Despite advances in tools of social media, that is not yet to take advantage under disaster circumstances. A disaster prevention system that incorporates disaster prevention education and open lines of communication among scientists, government, media, residents, and the tourism industry is necessary to improve the disaster resilience of communities in volcanic areas.
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Jukić, Oliver, Nenad Sikirica, Ivan Rumora et Mia Filić. « Seven days in Chile : Impact of the 2011 Puyehue-Cordon Caulle volcanic eruption on GPS ionospheric delay ». E3S Web of Conferences 94 (2019) : 01001. http://dx.doi.org/10.1051/e3sconf/20199401001.
Texte intégralRésumé :
Satellite navigation is a global utility and an essential component of national infrastructure. Disruptions of GNSS PNT services may be considered a threat to society and civilisation in general. Natural hazards may cause the conditions that disrupt or temporarily deny GNSS PNT services. As a contributor to ionospheric dynamics, volcanic activity is considered a source of GNSS positioning performance degradation. Here we studied the 2011 Puyehue-Cordon Caulle event, the largest 21st century volcanic eruption so far, in terms of its contribution to formation of Total Electron Content (TEC), the source of ionosphere-caused GNSS positioning error, and the effects the event made on GPS positioning accuracy. TEC values were derived from dual-frequency GPS observations collected experimentally at the International GNSS Service Network reference stations in Santiago, central Chile closest to the Puyehue-Cordon Caulle volcano. We identified considerable anomalous behaviour of TEC dynamics prior to, during and after the volcanic eruption, and examined the extent to which it affected GPS positioning accuracy. The research presented here will continue with the aim of characterisation of TEC anomalous dynamics around the eruption, and its effects on GNSS positioning performance.
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Bowman, Sarah J., Georgia Pe-Piper, David J. W. Piper, Robert A. Fensome et Edward L. King. « Early Cretaceous volcanism in the Scotian Basin 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. » Canadian Journal of Earth Sciences 49, no 12 (décembre 2012) : 1523–39. http://dx.doi.org/10.1139/e2012-063.
Texte intégralRésumé :
Early Cretaceous volcanism is widespread in the eastern Scotian Basin. The stratigraphic position of volcanic rocks within wells was re-evaluated and the volcanological character of the rocks was refined by study of cuttings and well logs. Hauterivian–Barremian volcanic rocks on the SW Grand Banks and Aptian–Albian volcanic rocks in the Orpheus Graben and SE Scotian Shelf resulted from Strombolian type eruptions. More extensive Hawaiian type flows were mapped from seismic profiles near the Mallard and Brant wells on the SW Grand Banks and they appear to have been derived from local basement highs with a positive magnetic anomaly interpreted as volcanic centres. Igneous rocks in the Hesper well on the SE Scotian Shelf are the erosional remnant of basaltic flows that terminated at the paleoshoreline. They correlate with basalt flows both in extensive outcrop on Scatarie Ridge and in several Orpheus Graben wells. The interpretation of the Hesper basalts as an erosional remnant of more extensive basalt flows is consistent with detrital petrographic evidence for substantial uplift of the inboard part of the Scotian Basin in the Hauterivian–Aptian. Widespread volcanic activity indicates a regional and long-lived magma source, which resulted in elevated regional heat flow. Effects of this heat flow are seen in sedimentary rocks of the Sable Subbasin and it had a discernable impact on hydrocarbon maturation.
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Lee, Sangchul, Namhee Kang, Minji Park, Jin Yeon Hwang, Sung Hyo Yun et Hoon Young Jeong. « A review on volcanic gas compositions related to volcanic activities and non-volcanological effects ». Geosciences Journal 22, no 1 (16 décembre 2017) : 183–97. http://dx.doi.org/10.1007/s12303-017-0056-y.
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Meziane, Rajae, Mohammed Diouri, Abdelmoula Ben-tayeb, Hanae Steli et Ouassila Salhi. « Effect of the main active volcanoes on aerosol optical properties ». E3S Web of Conferences 314 (2021) : 03007. http://dx.doi.org/10.1051/e3sconf/202131403007.
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Processing of the measurements obtained by the AERONET network of the optical parameters characteristic of the atmospheric aerosol carried out makes it possible to compare the optical effects of 2020 volcanic eruptions to those results for 2019 concerning Mexico City and Mauna Loa site. Both the monthly spectral means of AOD and the monthly means of fine and coarse volume concentration show an increase for the months of January and February 2020 (Volcanic eruption period) compared to the same period in 2019 at Mexico City. Those corresponding to Mauna-Loa seem not sensible with very low values. The effects of ashes of the two-studied volcano are very different, led to a low increase in optical depth comparatively to the contribution of anthropogenic aerosol at MexicoCity (low continental spread) and led to a nonsignificate effect at Mauna-Loa (high marine spread).
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Kamijo, Takashi, Minami Kawagoe, Taku Kato, Yutaka Kiyohara, Miyuki Matsuda, Keiko Hashiba et Kazunori Shimada. « Destruction and Recovery of Vegetation Caused by the 2000-Year Eruption on Miyake-Jima Island, Japan ». Journal of Disaster Research 3, no 3 (1 juin 2008) : 226–35. http://dx.doi.org/10.20965/jdr.2008.p0226.
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The active Mt. Oyama volcano on Miyake-jima Island in the Izu Islands, Japan, erupted in 2000 followed by large amounts of volcanic gas containing high concentrations of SO2has been emitted. The island ecosystem has been heavily damaged by the volcanic ash and gas. We detail the destruction and recovery of vegetation found in a 7-year study of 11 permanent plots from 2001 to 2007. Damage to vegetation by ash was worst near the crater in 2001. Trees began dying in 2001, apparently due to direct and/or indirect effects of volcanic gas emission. In contrast to the tree decline, two grass species,Miscanthus condensatusandCarex oshimensis, increased notably following the eruption, suggesting their high SO2and acidic soil tolerance.Miscanthus condensatusandC. oshimensiswere not dominant species in early stage of primary succession before the 2000-year eruption. In the vegetation recovery after the eruption, the tolerances to SO2and acidic soils are necessary for plant species to colonize on devastated sites.
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Bankoff, Greg. « Under the Volcano : Mount Mayon and Co-Volcanic Societies in the Philippines ». Environment and History 26, no 1 (1 février 2020) : 7–29. http://dx.doi.org/10.3197/096734019x15755402985532.
Texte intégralRésumé :
Rich volcanic soils have long attracted human settlements, which have traded the risk of eruption against the benefits of higher agricultural yields. Yet little research has been done on how societies have normalised the risks and adapted to living in proximity to volcanoes, or how those modifications, in turn, might have influenced the effects of eruptions and their consequent hazards. In short, people have co-evolved with volcanoes to create 'co-volcanic societies'. By looking closely at the Philippines and focusing on one region of southern Luzon around Mount Mayon, this article addresses the question of how people and the volcano have 'co-adapted' to living in proximity to one another over time. It also suggests that to make societies more resilient to volcanic hazards, a better understanding of this relationship is required not only to improve current disaster risk reduction policies but even to inform everyday urban planning and civil engineering decisions.
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PIPER, J. D. A., J. C. STEPHEN et M. J. BRANNEY. « Palaeomagnetism of the Borrowdale and Eycott volcanic groups, English Lake District : primary and secondary magnetization during a single late Ordovician polarity chron ». Geological Magazine 134, no 4 (juillet 1997) : 481–506. http://dx.doi.org/10.1017/s0016756897007279.
Texte intégralRésumé :
Late Ordovician volcanic rocks of the English Lake District typically have a magnetic remanence dominated by a single characteristic component. Previous investigations have interpreted this remanence as both of primary (pre-folding) and secondary origin. Palaeomagnetic field tests have been conducted on (a) andesite blocks from an autobrecciated lava top, (b) andesite blocks in mass-flow breccias, and (c) fault-blocks tilted during Ordovician caldera collapse to establish the time of remanence acquisition. All three tests show that the lavas retain a magnetization acquired during initial cooling: magnetizations of the breccias are coherent within clasts and random between clasts, whilst magnetizations of the tilted fault blocks converge with better that 95% confidence when corrected for the effects of caldera collapse. In contrast, the volcaniclastic sedimentary and pyroclastic rocks possess an Ordovician secondary remanence acquired after strata had been tilted by volcano-tectonic subsidence. A distributed sample of 65 andesite and basalt sheets through the Borrowdale Volcanic Group has a mean remanence direction D/I=341.9/−48.9° (α95=4.0°) yielding a positive fold test and a palaeomagnetic pole at 12.7°E, 4.3°S (dp/dm=3.5/5.3°). A progressive steepening of the palaeofield direction is recorded during emplacement of the Borrowdale Volcanic Group (∼I=−39° to I=−51°) which continued into the interval of volcanotectonic overprinting (I=−62°); the equivalent motion of Eastern Avalonia is ∼20° into higher southerly latitudes.Both the Eycott and Borrowdale volcanic groups exhibit uniform normal polarity throughout. Correlation with the geomagnetic time scale for the Ordovician restores the broad correlation between the two groups by constraining their emplacement and partial overprinting to a single long normal polarity chron occupying the Nemagraptus gracilis and earlier part of the Diplograptus multidens biozones (late Llandeilo and early Caradoc). All the volcanism, therefore, occurred within a period of no more than ∼5 Ma. The palaeomagnetic evidence confirms that the Borrowdale Volcanic Group was affected by both syn-volcanic deformation (caldera collapse) and regional compressive deformation prior to deposition of the (late Ordovician–Silurian) Windermere Supergroup. The succession of primary and secondary Ordovician palaeomagnetic poles from the Lake District inlier defines an anticlockwise apparent polar wander (APW) loop with the apex correlating with ‘soft’ closure of the Iapetus Ocean and late Ordovician deformation. The APW paths from Avalonia and Baltica converge at this point as subduction ceased and the arc subsided beneath the sea after mid-Caradoc times.
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Faggiano, Beatrice, Antonio Formisano, Daniela De Gregorio, Tony De Lucia et Federico M. Mazzolani. « A Quick Level Methodology for the Volcanic Vulnerability Assessment of Buildings ». Applied Mechanics and Materials 82 (juillet 2011) : 639–44. http://dx.doi.org/10.4028/www.scientific.net/amm.82.639.
Texte intégralRésumé :
Down the century, the volcanic eruptions have produced fatalities and economic losses. Today, almost half billion people and many conurbations (Tokyo, Mexico City, Yokohama, Seattle, Naples, etc.) are located in the proximity of very dangerous volcanoes. The volcanic risk mitigation of these areas requires a careful territorial planning together with an adequate knowledge of the behaviour of constructions under the eruption effects. The problem is very complex considering that a number of actions, such as ash fall, pyroclastic flows, flying fragments, volcanic earthquakes, lahars and tsunami, are produced by an eruptive event. Moreover, apart from the seismic case, the scientific literature relating to the structural volcanic vulnerability is poor. In this context, the paper illustrates a quick level methodology for the volcanic vulnerability assessment aimed at the identification of mitigation techniques. The ‘quick’ level, useful at territorial scale, is based on the identification of simple elements significant for the structures vulnerability. They are collected in a specific survey form, which adds to the information commonly required in case of the most familiar seismic vulnerability the ones specially related to all the volcano-induced phenomena. Then, the procedure furnishes a vulnerability index through the weighted combination of the vulnerability elements, according to the multi-criteria methods. The methodology proposed is a valuable tool that can be generally adopted in any kind of vulnerability investigation of buildings.
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Dagá, Joaquín, Alondra Chamorro, Hernán de Solminihac et Tomás Echaveguren. « Development of fragility curves for road bridges exposed to volcanic lahars ». Natural Hazards and Earth System Sciences 18, no 8 (8 août 2018) : 2111–25. http://dx.doi.org/10.5194/nhess-18-2111-2018.
Texte intégralRésumé :
Abstract. One of the main volcanic processes affecting road bridges are lahars, which are flows of water and volcanic material running down the slopes of a volcano and river valleys. Several studies have evidenced the effects of other volcanic processes on road infrastructure; however, limited information is available about the effects of lahars on bridges. In this paper, bridge failure models due to lahars are proposed and, based on these, fragility curves are developed. Failure models consider the limit state of pier and abutment overturning, and deck sliding caused by lahars. Existing physical models are used to stochastically characterize lahar loads and overturning momentum on bridges. Monte Carlo simulations are applied to quantify the probability of bridge failure given by different lahar depths. Fragility curves of bridges are finally parameterized by maximum likelihood estimation, assuming a cumulative log-normal distribution. Bridge failure models are empirically evaluated using data on 15 bridges that were affected by lahars in the last 50 years. Developed models suggest that decks fail mainly due to pier and/or abutment overturning, rather than deck-sliding forces. Moreover, it is concluded that bridges with piers are more vulnerable to lahars than bridges without piers. Further research is being conducted to develop an application tool to simulate the effects of expected lahars on exposed bridges of a road network.
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Waythomas, C. F., P. Watts et J. S. Walder. « Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska ». Natural Hazards and Earth System Sciences 6, no 5 (26 juillet 2006) : 671–85. http://dx.doi.org/10.5194/nhess-6-671-2006.
Texte intégralRésumé :
Abstract. Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12–14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.
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Lyons, W. B., P. A. Mayewski, M. J. Spencer, M. S. Twickler et T. E. Graedel. « A Northern Hemisphere Volcanic Chemistry Record (1869–1984) and Climatic Implications Using a South Greenland Ice Core ». Annals of Glaciology 14 (1990) : 176–82. http://dx.doi.org/10.3189/s0260305500008521.
Texte intégralRésumé :
The effect of volcanic emission of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869–1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60–90 °N. Many authors have pointed out that the amount of volcanic acids such as HCl and H2SO4 injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ∼1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism-climatic linkage.