11th October, 2017 eruption of Shinmoedake

Website launched: 2017/10/17

Shinmoedake amongst the Kirishima volcano group in Kyushu, southern Japan, erupted on 11th October, 2017. The previous eruption was 6 years ago in 2011.

Video shot using drone at 11:00 12th October, 2017

(Volcano Research Center: Fukashi Maeno)

2017/10/13

Aerial observation of the Shinmoedake eruption in 2017, Kirishima volcano group, Kyushu

Outline: Since after the eruption of Shinmoedake on 11th October, 2017, observation from Cessna plane (South Japan Airlines) was done on 11th afternoon, and observation inside/surrounding of the summit crater was done using a drone on 12th morning. Most of the plumes are emerging from the vent(s) on the east side of the crater. On 11th afternoon, the plume was mostly white, but became dark gray on 12th morning and intensity of the eruption and plume height increased. No significant difference inside the summit crater was found along with the activation on 12th and is considered to have erupted continuously from the same vent(s).

[Observation from the Cessna plane] -11th October 15:00-15:45: We observed Shinmoedake crater from Cessna plane (South Japan Airlines).
-White to grayish plume rising vigorously from vent(s), formed on the eastern margin of the summit crater. Majority are white plume, but sometimes we could also see some gray plumes. (fig1)
-Location of the vent(s) is part of the fumarolic area that existed before the eruption in 2011. It is also where a small vent was formed during the 2011 eruption.
-There are 2 vents close to each other. Though plumes are emerging from 2 separate vents, it looks as there are just 1 plume as they rise on top of each other. (fig2)
-Due to strong wind from the west, plume is heavily bent toward east and so the ashes are falling mostly on the eastern side of the volcano.
– A few to several tens of centimeters of ash layer (estimate) is covering east to northern side of the crater wall and the flank outside the summit crater. Fumarolic activity is more active on the eastern side of the crater, especially fumarolic area on the south west of eruptive vent is active.

Fig.1 Plume rising from eastern crater rim. Fumarolic activity is active around vent and some water puddles are also found.

 

Fig.2 There are 2 vents, and plume rising as one. (15:32 on 11th)
[Observation using drone] ・  On 12th October morning, summit crater and surrounding were observed using drone. Use of drone in the restricted area was carried out after arrangement with Kagoshima Forest Management Station.
・  It was filmed 3 times in between 9:30〜11:15, considering the wind direction and ash fall situation.
・  The position and size of the vents is almost the same from 11th, however, the plume was mostly dark gray and vigorously rising. (fig.3)
・  Ballistic ejecta were not observed but significant ash fall was found on the leeward side.
・  There are slightly weak plume, next to the vigorous plume. It looks as there are just 1 plume as they rise on top of each other. (fig4). We estimate that there are several vents.
・  Rising of plume is obviously stronger and higher than 11th. Possible reasons are wind effect declined and slight increase in eruption rate.
・  In the fumarolic area on the western slope of Shinmoedake, a temporal increase of the fumarolic activity was observed. Also, weak smokes rising temporary from several places on the western slope was observed.

Fig.3 plume seen from southern rim of the crater. (taken 10:55 12th)
Fig.4 taken from western side. There are vigorous plume in the back and weak one in front. But is rising as one when seen from above. (taken 11:05 12th).

(Volcano Research Center: Fukashi Maeno)