Stratigraphy, grain-size and component characteristics of the 2011 Shinmoedake eruption deposits, Kirishima Volcano, Japan

Miyabuchi, Yasuo; Hanada, Daisuke; Niimi, Hiroshi; Kobayashi, Tetsuo

doi:10.1016/j.jvolgeores.2013.03.027

Cited by 47 publications

(58 citation statements)

References 18 publications

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“…Fine particles of fresh lava occur together with recycled vulcanian products, which are lusterless, partly altered and oxidized. The dispersion and fragmentation index falls near the Surtseyan-field in the Walker diagram (Miyabuchi et al, 2013). After 10 September 2011, no further eruptive activity occurred.…”

Section: Vulcanian Stagementioning

confidence: 91%

“…During the volcanic tremor event, the phreatomagmatic eruption occurred and tephra of this event fell on the southeastern area of Shinmoe-dake on the morning of 19 January. The ash contained up to 10 vol% in volume fresh pumice fragments (Miyabuchi et al, 2013;Suzuki et al, 2013a). The majority of the ash is intensively to partly altered materials as same as the ash of the 2008 and 2010 phreatic events (Suzuki et al, 2013a).…”

Section: Subplinian Stagementioning

confidence: 99%

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The outline of the 2011 eruption at Shinmoe-dake (Kirishima), Japan

et al. 2013

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The climactic phase of the 2011 eruption at Shinmoe-dake was a mixture of subplinian and vulcanian eruptive events, successive lava accumulation (lava dome) within the crater, and repetition of vulcanian events after the dome growth. It was preceded by inflation and elevated seismicity for about one year and by phreatomagmatic explosions of one week before. Small pyroclastic flows and ash-cloud surges formed during the subplinian events, when the eruption column reached the highest level and the vent was widened. A lava dome, which was extruded close to the vent of subplinian events, grew by swelling upward and filling the crater. After the vent was covered by the lava, an intense vulcanian event occurred from the base of the dome and the swelled dome became deflated. After that, vulcanian events were repeated for three months. Simultaneous eruption styles in the crater (vulcanian events, continuous ash emission and dome growth) and some phreatomagmatic events in the vulcanian stage probably are due to a complex upper-conduit system developed in water-saturated country rock.

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Section: Vulcanian Stagementioning

confidence: 91%

Section: Subplinian Stagementioning

confidence: 99%

The outline of the 2011 eruption at Shinmoe-dake (Kirishima), Japan

et al. 2013

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“…inner and outer Mongolia and the Takla Makan desert; Shimizu et al (2004); Mikami et al (2006)) and can reach Japan, the United States or even circumnavigate the globe (Uno et al, 2009). Shinmoedake (part of the Kirishima volcano) erupted in 2011; however, ash was transported to the southeast, leaving the Kagoshima prefecture largely unaffected (Miyabuchi et al, 2013;Maeno et al, 2014). Initially, the stations were categorised based on their distance from the vent: proximal (up to 5 km from the vent), intermediate (between 5 and 20 km from the vent), and distal (farther than 20 km).…”

Section: Suspended Volcanic Ash and Gasesmentioning

confidence: 99%

Statistical analysis of dispersal and deposition patterns of volcanic emissions from Mt. Sakurajima, Japan

Poulidis

Takemi

Shimizu

et al. 2018

Atmospheric Environment

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A B S T R A C TWith 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 SO 2 in the area surrounding the volcano are studied here using daily surface observations of suspended particulate matter (SPM) and SO 2 and monthly ashfall values.Results reveal different dispersal patterns for SO 2 and volcanic ash, suggesting volcanic emissions' separation in the long-term. Peak SO 2 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 SO 2 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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“…The 2011 eruption consisted of numerous eruption events (e.g., JMA (Japan Meteorological Agency) and Yamasato (2011); Miyabuchi et al 2013). The first was a phreatomagmatic eruption on January 19, after which continuous fumarolic activity was observed in the crater.…”

Section: Shinmoedake Volcano and The 2011 Eruptionmentioning

confidence: 99%

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

et al. 2013

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We estimated time scales of magma-mixing processes just prior to the 2011 sub-Plinian eruptions of Shinmoedake volcano to investigate the mechanisms of the triggering processes of these eruptions. The sequence of these eruptions serves as an ideal example to investigate eruption mechanisms because the available geophysical and petrological observations can be combined for interpretation of magmatic processes. The eruptive products were mainly phenocryst-rich (28 vol%) andesitic pumice (SiO 2 57 wt%) with a small amount of more silicic pumice (SiO 2 62-63 wt%) and banded pumice. These pumices were formed by mixing of low-temperature mushy silicic magma (dacite) and high-temperature mafic magma (basalt or basaltic andesite). We calculated the time scales on the basis of zoning analysis of magnetite phenocrysts and diffusion calculations, and we compared the derived time scales with those of volcanic inflation/deflation observations. The magnetite data revealed that a significant mixing process (mixing I) occurred 0.4 to 3 days before the eruptions (preeruptive mixing) and likely triggered the eruptions. This mixing process was not accompanied by significant crustal deformation, indicating that the process was not accompanied by a significant change in volume of the magma chamber. We propose magmatic overturn or melt accumulation within the magma chamber as a possible process. A subordinate mixing process (mixing II) also occurred only several hours before the eruptions, likely during magma ascent (syn-eruptive mixing). However, we interpret mafic injection to have begun more than several tens of days prior to mixing I, likely occurring with the beginning of the inflation (December 2009). The injection did not instantaneously cause an eruption but could have resulted in stable stratified magma layers to form a hybrid andesitic magma (mobile layer). This hybrid andesite then formed the main eruptive component of the 2011 eruptions of Shinmoedake.

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Stratigraphy, grain-size and component characteristics of the 2011 Shinmoedake eruption deposits, Kirishima Volcano, Japan

Cited by 47 publications

References 18 publications

The outline of the 2011 eruption at Shinmoe-dake (Kirishima), Japan

The outline of the 2011 eruption at Shinmoe-dake (Kirishima), Japan

Statistical analysis of dispersal and deposition patterns of volcanic emissions from Mt. Sakurajima, Japan

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

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