A Chemical Analysis of the Volcanic Ash of Asamayama
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Volcanic ash
Volcanic ash
Vulcanian eruption
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A method for evaluating the volcanic ash discharge rate by using seismic and ground deformation signals is proposed to obtain this rate in real time for southern Kyushu’s Sakurajima volcano. This volcano repeats vulcanian eruptions accompanying significant ground deformation showing deflation and nonvulcanian type eruptions that emit the minor emissions of volcanic ash associated with volcanic tremors but without significant ground deformation. We examined ground deformation and seismic amplitude as they relate to monthly sums of volcanic ash weight ejected from craters. We found that in monthly sums, both deflation ground deformation and the amplitude of volcanic tremors correlate positively with the weight of ejected volcanic ash. A linear combination of terms for ground deformation, seismic amplitude and a correction factor correlates better than single parameter of deflation or seismic amplitude with volcanic ash weight. The linear combination provides the volcanic ash discharge rate in quasi-real time and the total amount of volcanic ash distributed over a wide area immediately after a volcanic eruption ends.
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After the prolonged disruption to aviation caused by volcanic ash injected in atmosphere via volcano Eyjafjallajökull (Iceland) in April and May 2010 aviation society in Europe established the system of three volcanic ash concentration zones (low, medium and high) based on correlation between concentration level and safety and allowed flight operations in areas of low concentration. Nevertheless, airspace unusable for operators and manufacturers is still demarcated by the presence of "visible ash" but the clear definition of that term is unfortunately not yet defined. In order to contribute to determining and using of the term "visible ash" the video that shows visibility level in the vicinity of volcano Eyjafjallajökull after the eruption in June, 2010 is used for the discussion. Several different snapshots are presented and information generated out of them used as the input data for a mathematical calculation of the visibility situation of the volcanic ash concentration boundaries upon which internationally recognized volcanic ash concentration zones are defined. In the end, a preliminary visibility threshold for flight operations in areas contaminated with volcanic ash is proposed and discussed.
Volcanic ash
Visibility
Vulcanian eruption
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With the eruption of Eyjafjallajökull (Iceland) in 2010, interest in the transport of volcanic ash after moderate to major eruptions has increased with regards to both the physical and the emergency hazard management aspects. However, there remain significant gaps in the understanding of the long-term behaviour of emissions from volcanoes with long periods of activity. Mt. Sakurajima (Japan) provides us with a rare opportunity to study such activity, due to its eruptive behaviour and dense observation network. In the 6-year period from 2009 to 2015, the volcano was erupting at an almost constant rate introducing approximately 500 kt of ash per month to the atmosphere. The long-term characteristics of the transport and deposition of ash and SO2 in the area surrounding the volcano are studied here using daily surface observations of suspended particulate matter (SPM) and SO2 and monthly ashfall values. Results reveal different dispersal patterns for SO2 and volcanic ash, suggesting volcanic emissions’ separation in the long-term. Peak SO2 concentrations at different locations on the volcano vary up to 2 orders of magnitude and decrease steeply with distance. Airborne volcanic ash increases SPM concentrations uniformly across the area surrounding the volcano, with distance from the vent having a secondary effect. During the period studied here, the influence of volcanic emissions was identifiable both in SO2 and SPM concentrations which were, at times, over the recommended exposure limits defined by the Japanese government, European Union and the World Health Organisation. Depositional patterns of volcanic ash exhibit elements of seasonality, consistent with previous studies. Climatological and topographic effects are suspected to impact the deposition of volcanic ash away from the vent: for sampling stations located close to complex topographical elements, sharp changes in the deposition patterns were observed, with ash deposits for neighbouring stations as close as 5 km differing as much as an order of magnitude. Despite these effects, deposition was sufficiently approximated by an inverse power law relationship, the fidelity of which depended on the distance from the vent: for proximal to intermediate areas (<20 km), errors decrease with longer accumulation periods (tested here for 1–72 months), while the opposite was seen for deposition in distal areas (>20 km).
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We collected volcanic ash immediately following the eruption of Mt. Asama on August 7, 2019, observed the characteristics of ash particles, and analyzed the water-soluble components. The volcanic ash consisted mostly of altered fragments, and no clear evidence of essential materials was found. The volcanic ash contained large amounts of water-soluble components, Cl and SO 4 at concentrations of 8,710 mg/kg and 49,100 mg/kg, respectively. These results indicate that this eruption was caused by the phreatic explosion and that part of the volcanic edifice of Mt. Asama was fractured and emitted.
Phreatic eruption
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Fumarole
Crater lake
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A volcanic eruption is a kind of global natural disaster that can occur suddenly and cause great damage to humankind. During the eruption, the magma causes fatal damage to life and property in areas near the volcano, and nearby countries are affected by the spread of volcanic ash, causing secondary damage due to air and soil pollution. Near the Korean peninsula, there exists an active volcano that can spread volcanic ash over long distances by erupting above Volcanic Explosivity Index (VEI) 4. Volcanoes in Japan have been known to cause considerable volcanic ash damage on the Korean Peninsula during eruption. Accordingly, the Korea Meteorological Administration is developing technology to predict and monitor volcanic ash spread using satellite images. However, despite the fact that empirical models for volcanic ash diffusion range prediction are used during volcanic eruptions, continuous improvement is needed for accurate information prediction. In this study, satellite images were analyzed not for the predicted distance of volcanic ash clouds, but for the actual distance of volcanic ash dispersion in cases where the volcanic ashes dispersed in the direction of the Korean peninsula. Of the 3,880 volcanoes that erupted in Japan over the last four years, 111 cases were identified where the height and spread distance of the volcanic ash that erupted toward the Korean Peninsula can be confirmed. In addition, the actual volcanic eruption cases and modeling results were analyzed to determine the extent of volcanic ash spread, and a hypothetical scenario was tested to quantify the direct damage of the volcanic ash. From the analysis of the volcanic ash spread through the virtual simulations, it was found that the height of the volcanic ash, the direction of the wind, and wind speed during volcanic eruption were important factors.
Volcanic ash
Peninsula
Vulcanian eruption
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Volcanic ash
Deposition
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Volcano Aso had frequent eruptions from 1979 through 1980, and a large amount of volcanic smoke and ash was emitted from its crater. The area spread over by the volcanic smoke and the area covered by the volcanic ash of this period were investigated by the optical analysis method of the Landsat MSS image. Volcanic smoke and ash-fall area were clearly detected from the Landsat MSS image. Their detectable area was seen to change with the transition of volcanic activity, and the maximum extension of volcanic smoke was about 70 km from the crater, and that of volcanic ash-fall area was about 10 km around the crater. By observation from the Landsat, it is possible to get information on the wide horizontal distribution of volcanic smoke or ash-fall, and the data from the Landsat are very useful for volcano observation.
Volcanic ash
Volcanic Gases
Vulcanian eruption
Volcanic hazards
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The aim of this thesis is to demonstrate the spread of volcanic ash in the eruption of Eyjafjallajokull volcano in Iceland in 2010 which disseminated all the way to Slovenia. We describe the threat that the volcanic ash presents for air traffic and, consequently, airlines, who suffered a huge financial loss. In this thesis, we mainly analyse the spread of volcanic ash in the first three days, when the outbreak was most intense and has spread almost all over Europe. For this presentation we used satellite images of SEVIRI sensor, which is mounted on the MSG-2 satellite. We also demonstrate methods and algorithms of detection of the volcanic ash in the atmosphere and satellites with sensors capable of detecting the volcanic ash on the basis of infrared waves.
Volcanic ash
Vulcanian eruption
Volcanic Gases
Volcanic hazards
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Abstract There are few pedological studies in Japan of fresh volcanic ash. Fundamental information of the material from which Japanese volcanic-ash soils have developed, is of importance to obtain a better understanding of pedogenesis of such soils. The present paper deals with the mechanical. mmeralogical, and chemical characteristics of fresh ash ejected from the Sakurajima and Aso volcanoes which are among the most active in Japan.
Volcanic ash
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