scholarly journals Explosive volcanic eruptions-IX. The transition between Hawaiian-style lava fountaining and Strombolian explosive activity

1995 ◽  
Vol 121 (1) ◽  
pp. 226-232 ◽  
Author(s):  
E. A. Parfitt ◽  
L. Wilson
Author(s):  
O. A. Girina ◽  
A. G. Manevich ◽  
D. V. Melnikov ◽  
A. A. Nuzhdaev ◽  
E. G. Petrova

Strong explosive volcanic eruptions are extremely dangerous to the modern jet aircraft as they can produce several cubic kilometers of volcanic ash and aerosols that can be sent to the atmosphere and the stratosphere in several hours to several days during the eruption. In 2016, five from thirty active volcanoes erupted in Kamchatka (Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Zhupanovsky) and three from six active volcanoes in the Northern Kuriles (Alaid, Ebeko, and Chikurachki). Effusive volcanic activity was noted at Sheveluch, Klyuchevskoy, Bezymianny and Alaid. All the volcanoes produced explosive activity. Strong explosive events occurred at Sheveluch mainly from September till December. Moderate ash emission had accompanied of Klyuchevskoy’s eruption through March till November. Explosive activity at Karymsky, Zhupanovsky, Alaid, and Chikurachki volcanoes was observed mainly in the first half of the year. The total area covered by ash in 2016 was estimated 600,000 km2, from which 460,000 km2 were related to the eruptions of Kamchatka volcanoes and 140,000 km2 were attributed to the eruption of the North Kuriles volcanoes. The activity at Sheveluch, Klyuchevskoy, and Zhupanovsky was dangerous to international and local airlines as explosions produced ash up to 10-12 km above sea level. The activity at Bezymianny, Karymsky, Alaid, Ebeko, and Chikurachki posed a threat to local aircrafts when explosions sent ash up to 5 km above sea level.


Author(s):  
O. A. Girina ◽  
A. G. Manevich ◽  
D. V. Melnikov ◽  
A. A. Nuzhdaev ◽  
E. G. Petrova

Strong explosive volcanic eruptions are extremely dangerous to the modern jet aircraft as they can produce several cubic kilometers of volcanic ash and aerosols that can be sent to the atmosphere and the stratosphere in several hours to several days during the eruption. In 2016, five from thirty active volcanoes erupted in Kamchatka (Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Zhupanovsky) and three from six active volcanoes in the Northern Kuriles (Alaid, Ebeko, and Chikurachki). Effusive volcanic activity was noted at Sheveluch, Klyuchevskoy, Bezymianny and Alaid. All the volcanoes produced explosive activity. Strong explosive events occurred at Sheveluch mainly from September till December. Moderate ash emission had accompanied of Klyuchevskoy’s eruption through March till November. Explosive activity at Karymsky, Zhupanovsky, Alaid, and Chikurachki volcanoes was observed mainly in the first half of the year. The total area covered by ash in 2016 was estimated 600,000 km2, from which 460,000 km2 were related to the eruptions of Kamchatka volcanoes and 140,000 km2 were attributed to the eruption of the North Kuriles volcanoes. The activity at Sheveluch, Klyuchevskoy, and Zhupanovsky was dangerous to international and local airlines as explosions produced ash up to 10-12 km above sea level. The activity at Bezymianny, Karymsky, Alaid, Ebeko, and Chikurachki posed a threat to local aircrafts when explosions sent ash up to 5 km above sea level.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eduardo Rossi ◽  
Gholamhossein Bagheri ◽  
Frances Beckett ◽  
Costanza Bonadonna

AbstractA large amount of volcanic ash produced during explosive volcanic eruptions has been found to sediment as aggregates of various types that typically reduce the associated residence time in the atmosphere (i.e., premature sedimentation). Nonetheless, speculations exist in the literature that aggregation has the potential to also delay particle sedimentation (rafting effect) even though it has been considered unlikely so far. Here, we present the first theoretical description of rafting that demonstrates how delayed sedimentation may not only occur but is probably more common than previously thought. The fate of volcanic ash is here quantified for all kind of observed aggregates. As an application to the case study of the 2010 eruption of Eyjafjallajökull volcano (Iceland), we also show how rafting can theoretically increase the travel distances of particles between 138–710 μm. These findings have fundamental implications for hazard assessment of volcanic ash dispersal as well as for weather modeling.


2015 ◽  
Vol 7 (1) ◽  
pp. 1077-1095 ◽  
Author(s):  
B. Bernard ◽  
U. Kueppers ◽  
H. Ortiz

Abstract. Explosive volcanic eruptions are commonly characterized based on a thorough analysis of the generated deposits. Amongst other characteristics in physical volcanology, density and porosity of juvenile clasts are some of the most frequently used characteristics to constrain eruptive dynamics. In this study, we evaluate the sensitivity of density and porosity data and introduce a weighting parameter to correct issues raised by the use of frequency analysis. Results of textural investigation can be biased by clast selection. Using statistical tools as presented here, the meaningfulness of a conclusion can be checked for any dataset easily. This is necessary to define whether or not a sample has met the requirements for statistical relevance, i.e. whether a dataset is large enough to allow for reproducible results. Graphical statistics are used to describe density and porosity distributions, similar to those used for grain-size analysis. This approach helps with the interpretation of volcanic deposits. To illustrate this methodology we chose two large datasets: (1) directed blast deposits of the 3640–3510 BC eruption of Chachimbiro volcano (Ecuador) and (2) block-and-ash-flow deposits of the 1990–1995 eruption of Unzen volcano (Japan). We propose add the use of this analysis for future investigations to check the objectivity of results achieved by different working groups and guarantee the meaningfulness of the interpretation.


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