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Table 1 Estimated gas composition

From: Variation of volcanic gas composition during the eruptive period in 2014–2015 at Nakadake crater, Aso volcano, Japan

Date Site CO2/SO2 H2O/SO2 H2/SO2 SO2/H2S SO2/Cl Cl/F AETS (°C)
(yy/mm/dd) No. Note (mol ratio)
Fumarolic gas
15/10/2003 3   5.0 26a 6.2 8.1  
04/10/2004 2   1.8 135 6.0# 15 13
26/10/2006 2   3.6 60a 0.010 6.0 19 500
19/09/2007 1   4.8 43 0.28 13 11 3.7 890
28/02/2008 1   2.2 20a 0.11 20 11 2.5 890
29/02/2008 1   2.1 35a 0.05 20 12 2.7 720
10/07/2008 1 e 3.6 45a 0.15 29 5.7 6.6 840
10/07/2008 1 f 2.2 50a 0.07 23 4.8 8.0 720
11/07/2008 1 e 3.0 65a 0.10 25 4.7 7.2 740
11/07/2008 1 f 3.0 55a 0.13 32 4.8 7.2 800
28/10/2008 1   1.7 40a 0.15 31 9.0 4.3 860
23/03/2009 1 e 4.0 70a 0.13 19 7.9 5.4 740
23/03/2009 1 f 2.7 60a 0.11 23 7.0 5.1 740
19/11/2009 1 e 4.3 50a 0.33 12 12.5d 3.4d 900
19/11/2009 1 f 3.0 44 0.36 17 12.5d 3.4d 950
19/11/2009 1 g 2.9 45 0.33 17 12.5d 3.4d 930
19/11/2009 1 h 3.4 37 0.38 15 12.5d 3.4d 970
06/07/2010 1   3.2 47 0.010 8.6 6.5 7.0 530
19/08/2010 1   4.5 89 0.05 7.0 5.0 8.5 600
01/10/2010 1   4.7 70 0.03 6.5 9.0 20 560
28/04/2011 1   10.0 80 0.010 5.0 9.7 25 480
05/12/2011 1   4.6 60a 0.013 13 120 540
27/03/2012 1   4.5 40 0.024 5.0 7.9 6.7 590
15/03/2013 1   5.3 40 0.07 6.0 13 5.2 700
06/08/2013 1   3.8 50a 0.11 7.0 15 7.5 730
07/10/2013 1   6.2 50 0.20 6.5 13 3.8 790
28/02/2014 1 K 3.5 30 0.07 6.0 16d 4.0d 730
28/02/2014 1 L 6.0 50a 0.05 5.0 16d 4.0d 640
06/06/2014 1   5.8 30 0.30 9.0 20 3.3 940
18/11/2014 1   3.1 64 0.30 6.0 8.5 3.2 810
Lake Gas
19/10/2003 4   0.8 3.0 33
04/10/2004 6   1.9 66 70# 107 1.6
25/04/2005 4   1.2 34 0.06 6.5 5.0 90 700
19/11/2005 4   2.3 56 0.05 59 210 1.3 710
26/10/2006 5   2.2 50a 0.020 50 100 18 620
27/10/2006 4   2.6 0.010 60 26
17/09/2007 5   1.7 190a 0.06 140 130 4.0 630
18/09/2007 6   2.0 120a 0.05 85 44 3.1 640
28/02/2008 7   1.4 80a 0.06 170 40 3.3 740
10/07/2008 5   1.3
11/07/2008 5   0.8 70a 0.05 100 79 15 710
28/10/2008 5   1.7 180a 0.05 300 90 3.4 650
23/03/2009 5   1.0 90a 0.030 2000 24 4.9 730
24/03/2009 5   1.0 100a 0.010 2000 28 9.0 610
06/07/2010 5   0.5 42 0.05 100 6.5 23 760
19/08/2010 5   0.7 80a 0.05 1000 13 17 780
28/04/2011 5   0.7 30 0.022 4.5 3.0 66 610
19/05/2011 6 K 0.5 20a 0.07 10 5.7d 8.0d 800
19/05/2011 6 L 1.0 45a 0.04 7.0 5.7d 8.0d 640
27/03/2012 5 K 0.34 54 0.08 200 55d 4.9d 820
27/03/2012 5 L 0.87 50a 0.06 20 55d 4.9d 700
15/03/2013 5   0.35 50 0.06 150 70 10 780
06/08/2013 5   0.7 80 0.08 40 10 23 710
07/10/2013 5   0.7 80 0.08 40 4.8 17 710
28/02/2014 5   0.8 0.06 10 7.1 65
06/06/2014 5   0.6 50a 0.20 60 8.1 3.2 900
18/11/2014 5   1.0 40a 0.05 500 11 2.2 840
During eruption
12/01/2015 3 A 8.0 30 0.11 3.0 770
12/01/2015 3 B 1.6 30 0.11 40 870
12/01/2015 3 C 1.6 30 0.11 300 990
25/02/2015 8 B’ 1.7 60 0.16 24 4.9 790
17/03/2015 6 A” 4.0 400b 0.10 3.0 2.2d 5.1d 510
17/03/2015 6 B” 1.6 70b 0.015 30 2.2d 5.1d 560
17/03/2015 6 C” 1.6 70b 0.008 300 2.2d 5.1d 570
19/05/2015 4   3.2 0.007 6.5 57 11 440c
20/05/2015 2   2.4 0.006 4.6 8.6 18 430c
20/05/2015 4   3.5 0.011 3.4 6.8 20 440c
20/05/2015 5   2.4 5.7 4.6 12  
  1. e, f, g and h are results of sequential measurements within a single day. K and L are end-member compositions of variable composition obtained by a single measurement. A, B and C (and their prime and double prime) are representative compositions of the variable compositions observed in a day during the eruptive period (see text for details)
  2. not determine, # Measured by the test tube (Komyo Rikagaku Kogyo Co.)
  3. aThe poor quality data with the correlation factor < 0.6, due to large variation in the atmospheric H2O concentration
  4. bThe poor quality data due to large variation in the atmospheric H2O concentration
  5. cCalculated with an assumption of H2O/SO2 = 100
  6. dA single AF sample collected during the multiple measurement of Multi-GAS