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Chemical compositions of volcanic gases from submarine
fumaroles in Wakamiko Caldera, northern Kagoshima Bay,Japan
+ ,+  -

 +3  /  +   +3  0  +, + +*,ῌ2//. !"#$%&'( ) 1ῌ+,!"* +,-.
2/,ῌ2/,+ /04/056-) +ῌ+.
/0 123

Yoshikazu KIKAWADA+, Joyo OSSAKA,, Takao OI+ and Jun HASHIMOTOFaculty of Science and Technology, Sophia University, 1ῌ+ Kioicho, Chiyoda,
Tokyo +*,ῌ2//., Japan,
Professor emeritus of Tokyo Institute of Technology
Faculty of Fisheries, Nagasaki University, +ῌ+. Bunkyocho, Nagasaki 2/,ῌ2/,+, Japan+

Abstract
The chemical compositions of fumarolic gases collected at submarine Wakamiko Caldera (depth7,** m) in the northern Kagoshima Bay, Kagoshima prefecture, Japan, havebeen determined. The gas samples have been directly collected using submarine researchvehicles from two distinct fumarolic sites ; one was on the knoll (depth71/ m) located at
the eastern edge of the caldera (Site-+) and the other was on the bottom of the caldera(Site-,).
The fumarolic gases were mainly composed of carbon dioxide, methane and nitrogen,and additional minor components were hydrogen sulﬁde and hydrogen. Hydrogen was
found in all the samples collected from Site-,, whereas determined in only a few samples
from Site-+. The contents of carbon dioxide and hydrogen sulﬁde in the gases of Site-,were slightly higher than those of Site-+. These results suggested that the fumarolic gases
from Site-, were more strongly a#ected by hydrothermal activities beneath the caldera
than those from Site-+. The present results were in good accordance with other ﬁndings
by the chemical and/or mineralogical analysis for the sediments, ﬂuids and bottom sea
water around the fumaroles.
Key words : fumarolic gas, hydrothermal activity, submarine volcano, Kagoshima Bay,
Wakamiko Caldera, Sakura-jima

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32

Fig. +The location and topography of Wakamiko caldera.

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Table +

33

Chemical compositions of bubble gases collected at sea levela
Content (vol. ῌ)Sampling
location

Sampling
date

H,S

CO,

H,

N,

CH.

O,

Site +,0-Nov-+31/,1-Nov-+31/,,-Sep-+310,,-Sep-+310,,-Sep-+310,/-Sep-+310,/-Sep-+310,,-Oct-+310,,-Oct-+310,,-Oct-+310,,-Oct-+310
0-Dec-+310
0-Dec-+310,*-Jan-+311+,-Sep-+311+.-Sep-+311,.-Aug-+312















*4**
*4**


*4+
*4+
*4+
*4+
*4+
*4+
*4+
*4+
*4+
*4+
*4+
*4+


*
*


*4*+
*4*+
*4*+
*4*+
*4*+
*4*+
*4*+
*4*+
*4*+
*4*+
*4*+
*4*+


*4***0*4***,


1-4+
1*41,42
1,42
1,43
1-4,
1.4.
1.42
1-40
1-43
1-43
1*42
1+4/
3140
134,
1,41
0143

+.4*
+341
+340
+341
+34/
+243
+/4+
+.41
+042
+04,
+04,
+34+
+24,.4,
+-42
+14/
,*4-

+,43
+*4*
140
14/
140
143
+*4/
+*4/
340
343
343
+*4+
+*4,
24,


++42

Site ,,0-Nov-+31/,0-Nov-+31/,1-Nov-+31/
0-Dec-+310
3-Dec-+310,+-Jan-+311,+-Jan-+311+.-Sep-+311,/-Aug-+312,/-Aug-+312

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
*4**
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*4+
*4+
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*4+
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*
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*43
+4,
+4,
*43
*43/
+42
*4+4.
,4,
+40

1.43
034.
1,42
0341
1*4*
/-4*
004,
014.
0*4.
0.43

+04/
,,42
+241
,-4,-4*.*4/,*4,/4-,4,
,14/

140
040
14,
04+
04*
.41
+-4,

/4,
04*

a

Data cited from Ossaka (+33+)

+302 

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FGH,

34
Table ,

Chemical compositions of fumarolic gases directly collected at submarine fumaroles
Content (vol. ῍)

Sampling
location

SampleNo.

Sampling
date

H,S

CO,

H,

N,

CH.

O,

Ar

3-Sep-+311
3-Sep-+311+,-Sep-+311+,-Sep-+311+,-Sep-+311,1-Aug-+312,/-Oct-+33.
,/-Oct-+33.
,1-Oct-+33.
,,-Jul-+33/+0-Apr-+330+0-Apr-+330+2-Apr-+330+-Sep-+331--Sep-+331+.-Jun-+332*4*,D*4**4**4*1
*4.1
*4,2
*4+*4,,
*4,.
*4/.
*4,.
*4.2
*4,.
*4.0
*4-/

1/4/
1/4*
1342
1242
2*40
2.4-1,41
1.43
1/42
1-42
0.4/
0*40/4/
2+42
/*41
1/4-

*
*
E*4***+
E*4***+**4***+**4***/*4***,
*
*
*
*
D
D
D

14,
14/4/4,
.4*
,40*
.40
,4+
,40
.4.
24/
342
340
D
D
D

+04,
+14+/42+/40+/4+,4/.
,,4,,42
,+4,
,*4/
,-41
,04/
,+4D
D
D

D
D
D
D
D
*4*0
*4*0
*4+*
*4+/
+4*,
,41.
-4,,
,431
D
D
D

D
D
D
D
D
D
*4**.
*4***
*4**.
*4*.1
*4***
*4***
*4+,0
D
D
D

a
a
a
a
a
a

Site +S+-+
S+-,
S+-S+-.
S+-/
S+-0
S+-1
S+-2
S+-3
S+-+*
S+-++
S+-+,
S+-+S+-+.
S+-+/
S+-+0

Site ,S,-+
S,-,
S,-S,-.
S,-/
S,-0
S,-1
S,-2
S,-3
S,-+*
S,-++
S,-+,
S,-+S,-+.
S,-+/
S,-+0
S,-+1
S,-+2
S,-+3

++-Sep-+311++-Sep-+311++-Sep-+311+--Sep-+311+--Sep-+311+.-Sep-+311+/-Sep-+311,1-Aug-+312,1-Aug-+312,3-Jun-+33*-*-Jun-+33*,0-Oct-+33.
,2-Oct-+33.
,.-Jul-+33/,.-Jul-+33/+1-Apr-+330+1-Apr-+330,-Sep-+331+--Jun-+332

*41+
*42*
*40*
*4.0
*4-,
*4.*4.0+4-*+4-1*4/*4//
*4+3
*4+2
*4+.
*4,/
*42/
*4-.
*4+/
*40+

3+4-3
3+4-*
214.*
3+4..
2143,403+41
3+40*
3+40124*1
2-42/
104,
3+41
1/43
2*40
034+
124,
2*4+
2.43

*4,0
*4,0
*4-1
*4,.
*4-1
*4,
*4,*
*4,*4,,
*4.+
*4-.
*4*,
*4*,
*41,
*4.1
*4*.
*4*D
D

,4*3
,4*1
-4,
,4+
-4,
+42
+42+
+41+403
14,+
.4-/
-4*
+4+
-4,
,40
+*42
14.
D
D

/4.1
/4/+
24/41
241
/4*
/411
/4++
.43,
+-4,,
+*410
,*4/
043
+34,
+/4+04+
++40
D
D

D
D
D
D
D
D
D
*4**4*1*4/.
*4++*4+*4+2*42.
*41.
-4+,4-1
D
D

D
D
D
D
D
D
D
D
D
*4*,0
*4*.+
*4**.
*4**,
*4*-+
*4*-0
*4***
*4+/1
D
D

a
a
a
a
a
a
a
a
a
a
a

a

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35

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5678 

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from Site-+ (open circles) and Site-, (closed circles).

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36

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circles).

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hiIJ jJkl kmn

f1g

/0AoEpqp c,de<  f/g r!sRS P WX 9&@f+0=f,-g

.tQ  uv

c,de< f,*=,,g r!



2 RD/(!0 wx ,*** ;,**,1 "y(45678& @ E

.

WX

9

[\ 0!z{|}~;Ny(' 45678@IJ:;[\ EM@

0 /01 45678 9&:;'
0E

 ῌ

0 t. 

*E



Fig. . Plot of the concentration of hydrogen against thatof methane for the fumarolic gases (closed circles) andfor the bubble gases collected at sea level (closed
triangles) from Site-,.

Fig.

mQ!9&m!3T

./01 IJ:; E}~;t.S/  E

 X

9& 3CD/0) @ E

N.

U./

0.]"9&  !
 ) @0O01-1-1.  '3G D/"& @0
]!(

GBs

01 Table ,RD/03T +330 ¡Gmz/n@¢£(¤Q  z
¥

]

O

( ¦§¨b

©y(&ª«@ny"2 aV./"1 tN. 2 G &
@0 UN G,¬­®

" &¯t.U°)0  z

Fig. / Plot of the concentration of hydrogen sulﬁde againstthat of carbon dioxide for the fumarolic gases from
Site-+ (open circles) and Site-, (closed circles).

zº»¼

38



!"# +33/ $%&'()*   +33. +,- +./ῌ 


/)

0

# 1

 23 456-78905:";< <= ,.> -? @!% 78 A2 A
 +.0. 6B- CDEFGH +32+I
J&' (!"KL MN%O ῌ 

PQ

0 2RS T
1UVW P # X9X0 7Y 1/
m NZ[ ,** m -45\"]X%
Fig. 0 Plot of the concentration of hydrogen againstthat of hydrogen sulﬁde for the fumarolic gases
from Site-,.

?

@^

`aLbc

78_ῌ2de f% ge^ # " 45hi78
Aῌ20%"j Oῌ 2

kbj%;< -^  Table , N%

lmnopN%(b 2 qrX"?st(bup vX"#-#-#/ wxyz&{

7|Y8} VS- 8~zy $-^ # -w` !"xyz&@z jTable , `"!X  G8~

 3a" CTable -I#!0

H,S-H,-CH.-CO, }xyz& CD’Amore and Panichi, +32*I

 Table -  T+ 0 #"!S

 P  Site-, - Site-+ Z#09 +/*> 90 ,/*>

 @z0 # "X% +31*   +33* Zz-^ +31*  +33*.
+33+ `90no$ %X"0 C+33,I PV1S #\00 C+33/I &X" CO,ῌH, xyz& T+ Z)z '<" CTable  T,I# X9X1 - 0 C+33/I &X" CH.ῌH, xyz&?k(z'<%X"!)g-^!"# 0 C+33/I Z

*$xyz& MJ

D’Amore and Panichi C+32*I xyz&+ <"-^ # 0 C+33/I *$

xyz&, ?k   G¡L- ¢£¤¥-V¦Z*§.\"-^ ge vX% #G-¢£¤¨©X%¥-*ª-$R'/«S

-ku " ¬6-*2­®0­878¯°±ge1-k"j
 } Marini C,***I NZ[ Giggenbach and Goguel C+323I Z!X" 0 - 

H,ῌAr z& "Table -  T- T. X%vS# T- ²³` T. ´²³`]US@z j%  8µ¶-8·¸¤´23X"j CMarini,,***I MKL0 z3X#  T- T.  T+ T, ¹z /1  ,**1 GHI@Jhi./jk:lMm9noq
Table -

39

Estimated reservoir temperatures

Sampling
location

SampleNo.

Sampling
date

Estimated temperature ()
T+a

T,b

T-c

T.d

Site +

S+-0
S+-1
S+-2
S+-3

,1-Aug-+312,/-Oct-+33.
,/-Oct-+33.
,1-Oct-+33.

2,

-,
22

-/

1/
/1




33




3,

Site ,S,-+
S,-,
S,-S,-.
S,-/
S,-0
S,-1
S,-2
S,-3
S,-+*
S,-++
S,-+,
S,-+S,-+.
S,-+/
S,-+0
S,-+1

++-Sep-+311++-Sep-+311++-Sep-+311+--Sep-+311+--Sep-+311+.-Sep-+311+/-Sep-+311,1-Aug-+312,1-Aug-+312,3-Jun-+33*-*-Jun-+33*,0-Oct-+33.
,2-Oct-+33.
,.-Jul-+33/,.-Jul-+33/+1-Apr-+330+1-Apr-+330

,.+
,.+2*
+03
+1,,1
,,1
,.1
,.0
+2*
+10
+/2
+0+10
+131
+13

,+0
,+0
,,/
,+.
,,/
,*3
,+*
,+,+,
,-*
,,.
+/2
+/0
,..
,-,
+13
+1+










,.3
,-+
,+0
,-,
,/3
,.
+-+










,/3
,-3
,,,
,.+
,1*
,/
+,1

a

Equilibrium temperatures calculated based on the H,S-H,-CH.-CO, geothermometer (D’Amore and Panichi, +32*).
b
Equilibrium temperatures calculated based on the CO,/H, geothermometer (Koga et al., +33/).
c
Equilibrium temperatures calculated for the vapor phase based on
the H,/Ar geothermometer (Marini, ,***).
d
Equilibrium temperatures calculated for the liquid phase based on
the H,/Ar geothermometer (Giggenbach and Goguel, +323).

 Site-+  +** Site-,  ,/* ! "# $%& Site-+

Site-,

   
'()*+,-./01* 2 345 6 1% 7% H,ῌAr 89:;<=>/?@ABC
:DE'(2F :GHI@J:$

KLM >/3N O P 6 Q=

RS TS UV:WXYZ[\?@AB]^_`a3bc P 6

M-d% ef3g52.ῌ ῎῍῏

GHI@Jhi./jk:lMm9no pRqrS s!B TS3tu  7:
vwq/S /S1xy I@Jim9z1h{|m9:}~  p
RqrS %:wq/S3 $F I@Jim9::/S1vd7= 

s²$

40




!


"

#$ % $&'()*+,- .#$/+ 012
34/ +56- 78 9 :ῌ;8  <=*>?64 12@/AB C
79D89EFGHIJ2=K  7L!+,- M"#N+
OP"

$%()Q6&68'R (STU .8>5) =*VTU :WKῐCU9X )YZ*6-

῏

+&'+

+33. "79 +333 "[VU6,&'\-]^_`./0a#N+,#N1

b80cd 23N] befgh -Kd 0#N1 bi7 ,***d  >49U6j5

$%()(S6- #Nk b80cd lm89E0anopq4/,&'\-]^r67898 c6- c6:1&'srt8uv;6
w5c6- xyz{c/c6+| , <=<Ns795V4>{}8u~?@AB8u~C

6D3

ETU6- yz6c/῎῍ῑῌIo W.S. +32+ : FGH- &IJK b,#$LMd ++/ῌ+.+ N 6$O N
D’Amore, F. and Panichi, C. (+32*) : Evaluation of deep temperatures of hydrothermal systems
by a new gas geothermometer, Geochim. Cosmochim. Acta, .., /.3ῌ//0.
Giggenbach W.F. and Goguel R.L. (+323) : Collection and analyses of geothermal and volcanic
water and gas discharges. Report N. CD ,.*+ (.th ed.), Chemistry Division DSIR, Petone,
New Zealand.
Hashimoto, J., Miura, T., Fujikura, K. and Ossaka, J. (+33-) : Discovery of vestimentiferan tubeworms in the euphotic zone, Zool. Sci., +*, +*0-ῌ+*01.

@P ,**/ : :- bQ+RS T - Od /.+ῌ/.,.
U V W XX &YZ Y, +33/ : CO,ῌH, [ CH.ῌH, [ H\\- Q+$ +1 ,*+ῌ,++.
Marini, L. (,***) : Reviews : Geochemical techniques for the exploration and exploitation ofgeothermal energy, Ciencia Abierta (Electronic Journal), N+,.

]^ _`a +310 : _`./ 3Nb #( ,1 2*1ῌ2,0.
c X ¡ 6d¢e £f g¤¥¦ §¤¨b X©ª «hIi ¬+ j
+33+ : _`./Vk :­® ¯6° ± lk Em# n ,²$³´Jhµoj¶&'(S ,-/ῌ,.-.
c ,*** : _`./·#$

·op²$¸q$ ,*** "*:6¹ºr»¼ Mc-**/.
Ono, K., Ito, K., Hasegawa, I., Ichikawa, K., Iizuka, T., Kakuta, T. and Suzuki, H. (+312) : Explosion
seismic studies in south Kyushu, especially around the Sakura-jima volcano, J. Phys. Earth,,0, S-*3-S-+3.

ª /1 « ,**1  +33+ : Sy:;§¨2348 ©541 ,,/῍,-3  !"#$ %&'( )*+, -. / 0 1 +33, : 23456

789:;<= >?@ABCDEFGHIJ 1/῍2*.
KLMN +302 : OP8 346QR ῌ 6Q8  +1 -3/῍.*/.
KLMN +32/a : :;9OSTU VWXY KLMN Z*[\] ^W _` OS
TU8  +῍++ $ !"# $
KLMN +32/b : OSTU5a VWXY KLMN Z*[\] ^W _` OSTU
8  ++῍,1 $ !"# $
bcde fghi jklm nopq rWst ,**, : uvwxyz{|}U~ OP  # ,**,  |# B**0-P**1.
 0(N l  cW( W 0 1 +333 : SyOP8    ¡C¢£ JAMSTEC ¤¥¦ +/ +./῍+/+.
Yamanaka, T., Ishibashi, J. and Hashimoto, J. (,***) : Organic geochemistry of hydrothermal
petroleum generated in the submarine Wakamiko caldera, southern Kyushu, Japan, Org.
Geochem., -+, +++1῍++-,.