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Table 5 Degassed-magma volume for 2011–12 and 2017–18 calculated from the bulk S and Cl contents of the magmas and volcanic gas observation. List of erupted-magma volume and crustal deformation estimated from geological and geophysical observations

From: Magma ascent and degassing processes of the 2011 and 2017–18 eruptions of Shinmoedake in Kirishima volcano group, Japan, based on petrological characteristics and volatile content of magmas

Date

Eruption style

Degassed magmaa

Magma eruptedb

Degassed magma/Erupted magma

Crustal deformation

  

S

Cl

 

S

Cl

estimated based on

  

(106 m3)

(106 m3)

(106 m3 DRE)

  

GPS observation (106 m3)c

2011–12

26–27 Jan. 2011

Subplinian eruptions

5

4

7–11

0.5–0.7

0.4–0.6

 + 18 ~  + 21 (1 Nov. 2009—25 Jan. 2011)

-13 ~ -14 (25 Jan–1 Feb. 2011)

28 Jan.–1 Feb. 2011

Lava effusion with Vulcanian eruptions

32

24

15

2.1

1.6

2 Feb.–7 Sep. 2011

Vulcanian eruptions, Ash emissions

18

13

 < 0.2

 > 90

 > 65

 + 11 (1 Feb–1 Dec. 2011)

8 Sep. 2011–26 Sep. 2012

No eruption with gas emission

3

2

0

  

Total

 

58

43

22–26

2.2–2.6

1.7–2.0

 

Date

Eruption style

Degassed magmad

Magma eruptede

Degassed magma/Erupted magma

Crustal deformation

  

S (B1)

S (B2)

 

S (B1)

S (B2)

estimated based on

  

(106 m3)

(106 m3)

(106 m3 DRE)

  

GPS observation (106 m3)f

2017–18

 11–16 Oct. 2017

Ash emissions

10

11

na

  

 + 11 (1 Jul. 2017–1 Mar. 2018)

 17 Oct. 2017–28 Feb. 2018

No eruption with gas emission

4

4

0

  

 1 Mar.–9 Mar. 2018

Lava effusion with Vulcanian eruptions and ash emissions

29

33

15(lava,

6 Mar.–9 Mar.)

1.9

2.2

−7 (1 Mar–10 Mar.2018)

 10 Mar.–27 Jun. 2018

Vulcanian eruptions, Ash emissions

5

6

0.3 (tephra,

1 Mar.–14 May)

17

20

 + 10 (10 Mar. 2018–31 Jan. 2019)

 28 Jun.–13 Oct. 2018

No eruption with gas emission

3

3

0

  

 Total

 

51

57

15

3.4

3.8

 
  1. aMass of the degassed magma was calculated from bulk S content of 0.072 wt% of A1 and A2 magmas (Table 4), bulk S content (0.0013 wt%) of the magma after degassing, chemical composition of volcanic gas and SO2 flux. The bulk S content after degassing was calculated from minimum S content of the groundmass of 2011-2SGP (0.002 wt%; Additional file 4) and the phenocryst content (28 vol%; Additional file 2). The SO2 flux used in this calculation are shown in Additional file 11. We also calculated mass of the degassed magma from bulk Cl content of 0.044 wt% (A1 and A2 magmas in Table 4), bulk Cl content (0.020 wt%) of the magma after degassing, the chemical composition of the volcanic gas and the SO2 flux. The bulk Cl content after degassing was calculated from minimum Cl content of the groundmass (0.030 wt% of 2011-7VL in Additional file 4) and the phenocryst content (28 vol%). Degassed-magma volume was obtained from the mass of the degassed magma assuming a rock density of 2500 kg m−3
  2. b Data on amount of tephra and lava are from Maeno et al. (2014), Nakada et al. (2013), Kozono et al. (2013), Nishiki et al. (2013). Erupted-magma volume of the subplinian eruptions on 26–27 January was calculated from total mass of tephra (1.8–3.1 × 1010 kg; Nakada et al. 2013), assuming a rock density of 2500 kg m−3. Erupted-magma volume on 28 January—1 February was based on that of lava effused within the summit crater (Kozono et al. 2013; Nakada et al. 2013). Erupted-magma volume on 2 February -7 September was after Nishiki et al. (2013)
  3. cCrustal deforamtion data from Nakao et al. (2013) and JMA (2019a)
  4. dMass of degassed magma as shown in S (B1) was calculated from bulk S content (0.063 wt%) of B1 magma in Table 4), bulk S content (0.0013 wt%) of the magma after degassing, chemical composition of volcanic gas and SO2 flux. The bulk S content after degassing was calculated from minimum S content of the groundmass of the 2018 eruptives (0.002 wt% of 2018-4L1 in Additional file 4) and the phenocryst content (28 vol%) of 2018-1VGP (Additional file 2). The SO2 flux used in this calculation are shown in Additional file 11. In addition, mass of degassed magma as shown in S (B2) was calculated using bulk S content of B2 magma (0.054 wt%; Table 4) and the same bulk S content of the magma after degassing (0.0013 wt%), the SO2 flux and the mol ratio of SO2 and H2S of the volcanic gas. Degassed-magma volume was obtained from the mass of the degassed magma assuming a rock density of 2500 kg m−3. Estimation on amount of degassed magma using bulk Cl content of the magma could not be carried out because of lack of data on mole ratio of Cl and S in the volcanic gas in 2017–18
  5. eData on amount of tephra and lava are from Chiba et al. (2018), Oikawa et al. (2018)
  6. fCrustal deforamtion data are from JMA (2019a)