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Volcanic Activities of Kuchinoerabujima Volcano
within the Last -*,*** Years
Nobuo GESHI῍ and Tetsuo KOBAYASHI῍῍
Volcanic history of Kuchinoerabujima Volcano in the last -*,*** years is reconstructed based on tephra
stratigraphy. Kuchinoerabujima is a volcanic island which is a cluster of at least nine volcanic ediﬁces ; Gokyo,
Jyogahana, Ban-yagamine, Takadomori, Noike, Kashimine, Hachikubo, Furutake and Shintake. Eruptions
within the last -*,*** years occurred from Noike, Hachikubo, Furutake and Shintake volcanoes. Two major
pumice and scoria eruptions occurred between +/ and ++ ka after an inactive period since ca. -* ka. NoikeYumugi tephra (+/ῌ+. ka, DRE*.*0 km-), erupted from the summit of Noike Volcano, consists of Yumugi
pumice fall deposit and Nemachi pyroclastic ﬂow deposit. Furutake-Megasaki tephra (+,ῌ++ ka, DRE ca. *.2km-) erupted from Furutake Volcano and consists of Furutake agglutinate, Furutake scoria ﬂow deposit andMegasaki scoria fall deposits. Volcanic ediﬁce of Older Furutake was built during the +,ῌ++ ka eruption.
Eruption style changed around +* ka, after the collapse of Older Furutake Volcano. Activities of Yougner
Furutake and Shintake Volcanoes are characterized with e#usion of lava ﬂow and no major pumice eruption isrecognized. Lithic tephra erupted from Younger Furutake and Shitake Volcanoes within the last +*,*** indicates
repetitive Vulcanian-type and phreatomagmatic eruptions. All historical eruptions since +2.+ occurred at andaround Shintake crater and were Vulcanian-type explosions with emission of magmatic materials and phreatic
explosions.
Key words : Kuchinoerabujima, eruption, tephra, Vulcanian eruption, phreatomagmatic explosion, pyroclastic ﬂow+ῌ ῐ ῎ ῑ ῏ +3-/ ; s2t +3-2W 9 +300

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Geological survey of Japan, National Institute ofAdvanced Industrial Science and Technology, +ῌ+ῌ+Higashi, Tsukuba, Ibaraki -*/ῌ*201, Japan.
 «23*ῌ**0/ #$%#$¯¶· +ῌ,+ῌ-/#$©¸¸
Faculty of Science, Kagoshima University, +ῌ,+ῌ-/Korimoto, Kagoshima, Kagoshima 23*ῌ**0/, Japan.
Corresponding author : Nobuo Geshi
e-mail : geshi-nob@aist.go.jp

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2

Fig. +. A : Distribution of the volcanic ediﬁces of Kuchinoerabujima volcano. Thick broken lines show theboundary of volcanic ediﬁces. B : Topography of Kuchinoerabujima. Localities of the outcrops described intext are shown with solid circle with locality number. Interval of counter is ,* m.

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Z-C0_c#b* )rs%t0WuAXv_E LLF=>?

*D@,-./#] CRLc#BO k YT]w3 ;"x4y4 +33/ ; }~VD@,-./#±²}~5z +331< D@!I#BJ3{ .** cm IB(W.M#$"7AC (Fig. 0) E

J^_K  -.0 km, "b I (Fig. /) Hayakawa

±²³.]´µC¶{=>?

(+32/) T$"O LF *.+2 km ;D@!#·] }~VD@,-./# =>-

%¹º» ¼»

8

Fig. 0. Distribution of Furutake-Megasaki tephra. A : Distribution of the pyroclastic cone deposit in the vicinity of
the crater, and total thickness of scoria fall deposit. B : Thickness of the lower major scoria fall unit (Furutake-Megasaki scoria fall +). C : Thickness of the upper major scoria fall unit (Furutake-Megasaki scoria fall ,).

 +*-* cm  

*,&'()c123 4 &'()d*OP (Fig. .)  !"#$%&'

!"#&'() + qU88 oV !"#$%&()*+,-./0/&'()123 4 '() + %>  3$%&'()K?@2A

5678139:; $%&'()*<OPKiK4 W *i3=6> , ?@2A4 %12!"#$%&'() +BCD , 6EF (Fig. .) GH$%&'()I
*&'()J:K /+* cm LM!"#* +.,3**+.,+/* ^_w +* cm  
^UV_OP .  !"#$%&'

K4 N=OP*!"#&'() + BCD , KQRS() , Q |12^_

3TUV !"#&'() + BCD , *WAXA4 Y

* ++,0-*++,,-* calBP (Probability3-.1ῌ) iT

Z[ \ ]^_ 6WA_`,&'()123  *aV

YZ[12^_512 +,,.-//* BP _  (,**,) * !"#$%&'() +,&'()bc4 d*e12f , /^UV A212 !"#km A_ghf  ,. mm i $%&'()

* +,,/**++,/** 6oA

*jk VlmT_&'()12n]oA &'(!"# TU¡]oA_¢)p*qrsK =4 W td*ghf £*¤¥1TU¦^UV_@W§¨@-/ cm i !"#$%&'() + %[*4 Q

6*©ªiK4 «L¢£ ¬d ,* cm uvwx&'()y8z/K{|^­®/6&'()®123¯ _[*4 ,&'()J TU}

°±^U²Me³´µ6¶·¡~zKM A^!"#$%&'() ,£¸64 W££* *.0* km- ¬­UV

¹º»89EF« - w¬E¼x

9&EFU/ <VWEFUa -*)/* cm Y
B#

]

-ῌ/



DEFF(%2=yFO>"az/. (Figs. ,, -) -./>"]{.|d?>
B @A}"#$'A}~Y/BCY.>"Y1 /* m *b/. DEF

D%EF2>"G% K-Ah az/.
]- / D%EF2>" 1,-** # ] b/. GF( HI]!+J / BD>"%2EFUK/

LM-/ /,/1*)/,/0* calBP (Probability3/ῌ) Na/. D>KB|]>"OF(/% "+ P>
"B QGP>EF %Y
Fig. 1. Relationship between the area enclosed byisopachs and thickness for Noike-Yumugi pumice
fall deposit and Furutake-Megasaki scoria fall
deposit.

 /+*, km- B P>#%+,*0*)3+* calBP E"# $%%i. (Fig. -)-ῌ0

DFRS E$# $%%i. T]E?+w ] (Figs. ,, -) --B- ,.*+*- kgῌm-+.,+*+, kg  !.** cm  !
,

+- km

../ km,  ,** cm "#$ +** cm  !Hayakawa (+32/) &'(-* km, %./DE# $ !

g  0.2.3

m JU'E8V%W?2DE#$Y 2* m _GB X

SYa9:2

 (Fig. 2) E8V%W?2DE#*.,,)$Z[]EF7/  S k7O\*.-1 km !*+ +.*+* kg ῌ]^%  7.^1 /* cm *B _`



-

m-

-

, ,.,)-.1+*++ kg  (Fig. 1) -.

a¡?b¢cda9:2|a/2£¤Y.

/012  345 +.0DE# $K%e2¥E6# m¦s§BSY.- ¨2fg0a/. +*+, kg(DRE *.2 km-)-ῌ. 

DE# $%e2>"a(K-Ah)

K-Ah !67 +312]89 .*(Fig. 2) FROG 0-- m ©vªh«B yFkm :;<=>5/ 1,-**  ! +33/ %

Od?>aS E# $¬%. ]

? @A345B C6D6EFGH(Fig. 2) -yFO>S­i

I89JKABLBM 89B>G'>klG"'®m b/. D

 345N!OPQE"# $ !R7 +31-

E# $aP> ¯D>?

 S.%5OBT&EFU<VWEF

°Bno,%? - ¨j/P

]

U !67 +312 /  PQE"# $OU)O'F( HIh«BDE:;<=>5% 'F(B /* cm)+ m, )XGB

# $±²³ªst³´µ4²v# $ !D-* cm *YB Z+B[\,%I#E"# $ !

]%p¶2  HI]% N!-.^ / cm _+`0a/]a [\,%\]qr·°Bs¸

±²³ªst³]`\B.^ -* cm 0b1cN!

´µ4²v# $ae2=9:] DE

I#

dae. S#

`\B

f

f.^2 +*

cm %"#gh3-a4i. E"#$j5"# $]{.|Z[]EF7/  e
.EF79t]8 -aJ °¯B%6&k)T7lmn8 -opq-/ a¡?b¢cda9:2 jOT&$%u ]EFY2 cm r5stumWv (Walker et al., +32+) ak/  f fLv$-/%e°B] +9:2`0a/] E"# $%w  ;x<T

J 0 BP>.G±²³ªst³´µ4²v#

3»¼B67CB

10

Fig. 2. Schematic illustration of the outcrop of Younger Furutake pyroclastic cone deposit exposed in the western
rim of Furutake crater.





+,*0*

3+* calBP))Qo ,.2 km, $ ,./ km /v'1  w(Probability 3/ῌ)    

TCBx - y"#zp{|}hO5 +~6

 1  !"#$8 ,**, ,h-hO5GOO"

#zp{\h-,,,*,,3/* calBP(Probability 3/..ῌ)

%&'

Q

-ῌ1 

/*

km %&5 +~68 (,**,)-()*+ ,-  ./01 23!"#$ #zp{

67 +33- ; 768 ,**,

9:;1<

KB1I5

=()*>$%?<*>$%&@,..+*+ <))Q"#zp{/1(/0I <))Q"45/2* m %&5 .<))/\hIOx 2 1TI ++ / 

-ῌ3

AA% BC/*>$ <D BEF A

<)-n*+e2/  <))Q3'1}9**>$ ()*+G ,H/ 1>$Z  I*>}1I5 (Fig. -)

I5J (Fig. -) GKL ()*+BMNO5

AA% AO<)*+.4$<)*>$A*>$/PO5Q R%SI <D BEF <)*>$ /R%

TU-QT@ VWXYZ[45 (SITU-QRQaB*-6 *-T) ,- % *>$9\  + m % ]@/}9|Z /[1I5 |} ¡/!ITQT5^R/2_?` .

_¢5£¤I 6¥¦T§7¨$zpm U-QaZbc1I5 de"# , fg .

{Z8©%ª5 A*>$/ VWXY

Fig. +A  1 $  ,** m % \h 1* cm «yT*-¬¢­9W*-¬Zi¨PO5

 !"#$B1 1I5

AO$ 9*3'1RQ/:®¯°±*>$/

;45\h?` , m <=QR²"³Z[467 (+33-)

Zi%/PO1j@ A*>$ ,**k2* BP  7 6 8 (,**,)

+1,/῍+2+-

 (Probability /2.*ῌ) &l'(m1I5
-ῌ2<))Q  <)-n*o/3p qrs
tu/[45U-QRaW)Q%&5 (Figs. , , -) <5 AO<))Q´@<I*>9 9\ <)-n*+e2%,*-* m %&5Z *+>O5/yO1µ¶/G9\Z·w45
<)o-? -** m.@O¸¹I/  !"#$ZAK1I5 P
O5Q`*% ººVWXY

¹º»¡bM 
  

¢ª= - NH¼ /11  

 !"#  $%&'()
"*  $+   , -.
/012)+ !3456!"-ῌ+* 

789:80; <=>?@A
BCDE0 K-Ah FGH
IJK L MKN 

O,P)( (Fig.

3) "QRABC; <=>?@QRSTUV

DE0W" X1YZ,[<\ ]*[(" (Fig. +*A)  .<

X1Y

 02)^\QRP3ABCHW

56 ""H;"ABC_`aP)<
\=bABC cde fg 7
8H; <\=bABC;[! - m h6
"

O,0;

 #i N-m # N+LN0 *ABC,!j (Fig. 3)
bABC_0

"ABC;Zkl0 , m"0n op; N-m ABC# N/ ABC0q#! $H%r sk



X1Y

NABCH 4op; N-0 ABC0q#! ! t &'0(u)23 v*+w,xpABCHW
 $lyABC ;]zOKLO.K G*-P)(( "0;(u{|;}~ 
?CS/xP)( $;0123x

34 5  0

3PP #3xp


,0





;y + R

Fig. 3. Schematic stratigraphy of the tephra younger
than ca +* ka (Furutake and Shintake - Nagasako
tephra) in Yumugi area, eastern part of the island.

HW w,;623+?CS, (Fig. ++)78P3& (~4]G*(u;}(3?CS,;-;]¤0¥32)C|¦DHW& Z¢@£I  -xp,;HW;<\ ]*@§(3j "ABC¨©

"1$lyABC,0;P< ¡W(; ¡Eª4^!3"

P9  `: (u«P)( (Fig. +*B)

3 N-0 ABC,[4lyABC;! t &'0(u"ABC¨©< ¡Eª4^!3"

nJKL.KP3 «P)( (Fig. +*C) ? 2 H N-m ABC¬;*+HW& ; <,
<\

3w,



¡= ,./ km :7>: c?

%P39F -,.1*L-,-,* calBP (Probability­
3,.-ῌ)

? N-0 ABCGR9F +,-3*L

2e H; K-Ah = + m DE0¢@£ /L1 cm +,,2* calBP (Probability­3/..ῌ) HqZ®I 0 IABC!j cN-m A

3*

BCe ZDE= /* cm 0;JKA

* ¯°±:? +0 0) N-m ABCGDJKq². c L³´µ¶·e +¸¬%P3

0BIABC cN-0 ABCe !j N-m ABC

yz{|\#}|

12  3

+.2 km

 N-0  !" #$%&

R+S

038T,-. (Fig. +*E)/ 0

UVWXYZ&[6 \ []&'()*+,-./ 0012&)34 / 5!

6789:;.03'1<. (N-+=/ ; Fig. +,)/

&1 N-/ Z\ef&g[A7AB&!^1_:`ab cd3&./ 00>? N-, @7ABCDE FG HIJ8

! hijklmB8n031opqr  s

K;. L )MN1<./ OPQ N-, '0 t uv;.03WXYwx MN1

N-

Fig. +*. A : Total thickness of Furutake and Shintake-Nagasako tephra younger than K-Ah (1.- ka), B : maximum
size of lithic fragments of N-m tephra (average of the largest three lapilli), C : distribution of the thickness of
N-0 tephra, D : thickness of N-/ tephra, E : thickness of N-, tephra. F : Furutake crater, S : Shintake crater.
Thickness unit is cm.

 ¼7YJ 16/{ - ZH1E"

13 ;=^_`a 2 0N 2&H +3-.a,b3 89WX;b1 c&N2&d

3f /+* cm 4g6LM=h9ec g6LM4i[5# 6jk7lm *=#8 P

459n6/o:(<p; +3-,  +3-. D q q<r%s=t>u% v?%s@wcxyz
89<p;A{2J +3-23(=t>2)

2}~|s=-. DB%#G

P



|

 +3-,

2& +3./  ++ V - -#G

1s-.zs= 456.7 17u
qm *17#GN2  Ch 2BC! ,**/3 c17D +3./ N2&de /E =%

, m 4FGy c ( +300 1N2He +300  ++ V ,, - 45617$#%1=#G

IJ.J>=$z 

96KQ+R)NLM=Ch

2 BCL[   +3013 YZ16LMu%96K&(Q+R#6,1T=#G  056
JI6KD13?c1'x

Fig. ++. Glassy grains in Furutake and ShintakeNagasako tephra. A : Angular glassy grain, B :partly-vesiculated glassy grain.

N2&  ¡g6LGyA16
=M  P 4569NOD
1  3f] m u¢4isg6LM#He 
Ps£Q¤¥¦=; c 16LM

 (Fig. 3D)  3  N-/ 



|£Q¤¥¦ +300 1§*O

16LM

 3-*1.* calBP (Probability3/..ῌ) 

Ch¨ 2 BCL[   +3013





 P

( +32* 1R=N2

He



 +300 1N2&

 

 ! 1.1"+* m #$%  +./"+*





-

) +31* D4517B%©1

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1-

N2¬SM­(c&T.  +32*  3 V ,2 - 456.I9®-./01 +2.+  2 +, 3 # 4
5617189:;<16=>?&-=$=)@A#$ 2BC! ,**/3 +3-+  -/ D4517#1E"=E#  FF$#%1=#G

2&H

+3-.a, b ; I& +3-/ ; J +3-23 $#%1'

K(LM)N=*OG P Q+RS,1T=#

2J +3-23 &U +3--  +, V ,/ -

1#./WX;YZ16[LM=\]>?

¯°m *171 In<16=Ch

2±UE²VT³´[µ +32+3 N2,¯°6W¶·( P¸Ps4(¹FºD
LM& R=AX2s 2±UE²VT³´[µ +32+3 89m *17D1  +300
N2Hz/E

+ m 4F 1

6R= =%.° m*17In45[056J1 ]cm 4FL»yR=

=B%

,

14  +32* 

  ! "#$%&'()*+,

?

j9klm=nNo?pjqr

s3tuv?wq7k /,/1*`/,/0*-. +32+/ 01. 2 34560a (*,++*,L+ ; Table A+) 9:U. 

7 +32* 89:0;<M=>?yz{| %@v9Z[0;<xv9Y v. YM=>?D} K-Ah / ~ 7. =M=>? EF_ +,,*** a/ῌ+ 

7_ /,0** a ^9. TVA K-Ah=>?. %@ABC ?DEF GHIJ0;<  KL=M=>? EF GNOPQ

a

YM=> EFoOPEF GST

RGSTU. V WSXJYM=>?HZ[U. V WY>s3H H] (Fig. -) YM=

 (Fig. -) \]. =M=>? EFM=> EFYM=>S]07

M=>? GZ0YM=>? GZ ^9: =. TV -,*** aGZ0;<M=>?. _ +,,/**`++,/** a =>bcdevY>s3 8n_ +,***`+,,** a "2  8f]gM^Z[ hi. YM=>

~ ++  ; ,-. ,**,/ 0

Fig. +,. Representative sections of the Furutake and Shintake-Nagasako tephra around Shintake and Furutake.
Thickness unit is cm.

z{¼AB±² - 'V I
  -,*** +,*** 

15

YVH ;S W> 6.S B
y.$  5/PQ*S   M2en6WXY.cdpX'O

  ! "#$%  &'    $I\ +3-+ +3-.  +300 )*( , )  *  +

cd 010.NO$r

 ,   - .$  /010 23456
789: * 010

C 

YZ

AO +3./ +32* WXYS&SS[L1.2e$\^ S]7q89$*5;<5 =>. $?.

n6 S S^ ,@ St. Helens +32*  Moor and

.['

Y¡e

^¢

1.2e$\^_`S P 1.2e.£g¤na..ab^O

Albee, +32,-/ῌ, 



$  2en6$[AB' +2.+ CD EF .

WXYH  010 e S M¥

G H* !AI5J! K  P ¦B(WXY /" LM#$' N% 

N-0 WXY N-, WXY 2en6$[

O

&PQI5JR ST

U + 'V I5J OP +32* h)* .ab § ( O )*  5/ TU + 'VO P ¦

&$[WXY'(\ TU + 'V]

B(WXY bc M2en6$[cd 

B(WXYZ EF^EF( +2.+ CD)*LM#$

$_\+,-
S' EF( +2.+ CD

O '(\  PT[' AJ( AJ:010 e.$R/O` ¨©ª«¬: (Morrissey and Mastin, ,***)­ .®

.ab$'(\ cd 010 e /O fgd S  AOhi ,@bj0 +33+- ¯e +3-+ -.  +300 'Ok]WXO '(\  ,** S' A*010

M2en6$[cd

Y 1.2e$lm34'5n6$[. fS'g:¯e.

 /op 7q89.:* *;rs

S t <1nu =O.E/ῌ-    ,>V +3-.a, b- ? @v w

 I5J OB(WXY

AxBy. ,z{CbjDP|

Z OV   hnZ hn Ot

}-~ +301- +3-, ' E.?

°i ±² + 'V I

@5\F ,>V +3-.a, b- h  P jA hn eO©ª«¬:$cd ?.OP@$ _\+ ! V2en6WXY$/O5/.

 GH-.  I 

ab.],-  I5J

AJ.<1$KI\ <1 dL  bc hne  P

1**(+3-2)

 +3-+

2** :,- ^/O¯ '(B(WXY M2en6$[WXY$OkS !l² ¯³

 +3-+ +3-.  +300 '  cd 010'(\  P  kS , -´+*+, kg+* ce.NO,- P /OB(WXYZ / M2en6[WXY n6* * +.,´+*++ kg+ C'( B(WXY Dµa¡¶7·h 010 O5¯$O .f-. ghS* TU + 'V AB

+300 5O )* fghO

 010O*:.hne['(^$34'5=n.[' 1.2en6

+3-++

C'(  5n6 /op7q89.

¸ ¹º hne  ) 'O

PQR: SS Tp U$010 S$s *  P O?*S  5/M2en6$[WX

hne/ ±bhnehn' ,..´+*»+¹º»L}¼»

16

Fig. +-. Summary of the volcanic activity of Kuchinoerabujima volcano. Representative overlap-relationshipshows with arrows.

km-   -
  !"# 2

& Hwx()*+,-@7y(+,-# K`Th
WXWIpq/z{T#0D?H>,T$+*%, km- & '()*+,-. (/0| OPQRS>,#pqHWXW10# /$+*%, km- & 0 23{T~/& 6 >, S # @A45/ 67*()*+,- 0 

WXW2  T & h1089:;& <=()*+ (+>?/ +  0#@@7A +*%, kmB C

I}z

WXWIpq/z{T# 2 IWXWI2T?/0>, !"DEFGH6IJ& K

WXWIpqHz{T#TTH()*+L(+MNOPQRS>,T7=2 T7  DVOPQ + UV?WXW Y # Z[\ ]RS>,#WXW>,T|= &Y @7A /$+*%, km- ^"  _WXWOPQRS>, :; ¡0¢`D ,./$+* kg ῌ m abc& 6>,\ ]#£¤DEF¥¦ 0¢I§!

6 6# Kd 0D?H>, WXW>,-­®T¯ (Fig. ++)& 6#WXWI°? I OPQRS>,T7WXW >? Tfg

6Div/@  Div/&

-

-

#+d

>?/ +  0 !"8e`& ¨k#¥©=3DiH~` ª«]¬¡#ThJ6Di/@ jZ kl,-#/ῌ.  - >,mnoT@VWXW pq I>,3r

jZ

Dso

PHt  u6Div/

kl,-

 

. -*,*** U±²³TF´µ¶ ·^D' (Fig. +-)& jZ kll¸Xuv%&  ,3,***  AT 

  AT  

T7 - ¯ '     AT  !"#$  +/,*** $%&('$ '"')

*+ +/,*** , ++,***  %&$ , -.
+/,*** 

/  +.,***0 $ 1 *.+2 km-  !2   *.,km- 2! / %&"#$%"&3'( +,,/**0++,/** 4

56)7$8*!

9 :;:1<=+>?@A ,B A;CDEFG,5H56.I!>?@A#"&KL0/J! 5H56MN12,3O
5H56

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78 6H56

   9.$ ' %,QCRS:

 "; =+ /   6
H56

T6  +2 <UN=, +3 <U>? #$% /  ! 66
V66 W   MX

',- .YQCRS: 0@AZ $[ 6H56
BC =+ /   66$ ,* <U , B''D\ :;:E!"QCRS: ῏῎]F^G_`aH'`abcdFe%IJ

f %&Kg0LhijMk. NOlP"k Qm^nRf opqSr`aHTUsVft$WPk XuvY*mZw[^x7\s]fXuv^_`bcdF# ayfzbc{|d}e"k ]F^G_`aH'`abcdF tKg

'~90f-ighk , ijigkl?cGmPnop$[ qῌ ῑ ῐ ῍ +.
rNs (+303) %&4!Kgt
+,1ῌ+-,.
uvw3xyzV (+33-) %&4!T7 ' 4{T^|^ +33- rB17}~ -,+.
Q] (+33/)   3 o '(E U`a -. +-/ῌ+.3.
Hayakawa, Y. (+32/) Pyroclastic geology of Towada volcano. Bull. Earthq. Res. Inst., Univ. Tokyo, 0*, /*1ῌ/3,.
m (+3-.a) a 2  +, a 3  + %&66' 4 ,+ ,.-ῌ,00.
m (+3-. b) %&
4!
'
VW
 + ,*ῌ-3.
e%IJ (,**,) %&

' 
+33,  0 ,**,   09O'
~r
3 %&
~r
 3  
 11ῌ20.
Xu4ZZ 3 ¡¢£H (+301) a .+  ++
 ,, %&66t Qm¤¥Z
ZOt ,, 13ῌ32.
Z VW (+33+) m' V , W .**ῌ.*..
Z VW (,**/) m' V - W /13ῌ/2-.
Kitagawa, H. and van der Plicht, J. (+332) A .*,*** 
years carve chronology from Lake Suigetsu, Japan : extension of the +.C calibration curve. Radiocarbon, .*, .3/ῌ/*..
xyzV37\s] (+332) %&4P34!
XuvYE¦ XuKg§ptῌ ¨ 30ῌ+*-.
xyzV3n R3V (,**,) %&
~r   © 09O'
3%&
~r +03ῌ+2..
]F^G_`aH3#]ªp^ª^3Xu^^ (+32+) +32*  V3  ,2 W %&66
 } |t ,* +ῌ3.
 V«tW®
 36e V (+310) ¬­¡¢¯M°± ^ .0 --3ῌ-.1.
 Tn
 36e V (+312) 1²£³´RCµ, U`a +1¬­AR¶·+.-ῌ+0-.
 36e V (+33,)
AG>m¤M¥¦ #]^ ,10 p.
 36e V (,**-) 6
AG>
m¤M¥¦ #]^ --0 p.
 , +ῌ§m¨ (+3-/) %&4!©+3.
ª¸¹3e%IJ3º?«V3Solihin Agus (,**,) %&66  54»Z^¬e 0
3%&
9O'
~r  ~r +/3ῌ+02.
Miyashiro, A. (+31.) Volcanic rock series in island arcs
and active continental margins. Am. Jour. Science, ,1.,-,+ῌ-//.
­® ¬3Westgate, J.3Sandhu, A.36e V (,***)
1²£H¼6< Isothermal plateau ﬁssiontrack ¬M U^°± 4{T^|^ ,*** rB}~ Qa-**..
Moor, J. G. and Albee, W. C. (+32,) Topographic andstructural changes, March-July +32*  Photogrammetricdata. In The +32* Eruptions of Mount St. Helens(Lipman, P. W. and Mullineaux, D. R. eds), +,-ῌ+-..

ª«¬­®¯¬

18

Fig. A+.

Whole-rock Na,O©K,O content and FeO*/MgO ratio plotted against their SiO, content.

USGS Professional Paper, +,/*, Washington.
Morrissey, M. M. and Mastin, L. G. (,***) Vulcanianeruption. In Encyclopedia of Volcanoes (Sigurdsson et al.
eds), .0-ῌ.1/. Academic Press.
  (+33/) 
  !"# 1# +ῌ,-.
Ramsey, B. C. (+33/) Radiocarbon calibration and analysisof stratigraphy : the OxCal program. Radiocarbon, -1,.,/ῌ.-*.
Ramsey, B. C. (,**+) Development of the radiocarbon
program OxCal. Radiocarbon, .-, -//ῌ-0-.
$%&'( (+3-2) )*+,-./)012
3456789: 8# .# --3ῌ-/..
;<=> (+31-) ?@ABCDEFGHIJKLMNABOP 8# +2# +/-ῌ+02.
Walker, G. P. L., Self, S. and Frogatt, P. C. (+32+) The
ground layer of the Taupo ignimbrite : a striking example
of sedimentation from a pyroclastic ﬂow. Jour. Volcanol.
Geotherm. Res., +*, +ῌ++.
8QRS (+331) TU
VWXY.8
Z [\# +*-# 010ῌ03+.

ῑ ῒ
A+ῌ

C ῐ῎῍῏+.

]^_`a# )*+,%bcdefghi
jk +- l+2 mnkopN# gq +. rstuk

vw  tuxyk Table A+ b# mnoplk Fig.
+ % b z { g q +. r s t u a | } ~   ^ _ (IAA) 234 Beta Analysis Inc. USA (BA) bN# |}~[

(AMS) kFtuN

 mna

e /NFCCkvw  gq+. rsa Libby kFN# mn d +- CkFN  tua +.C tb ¡H¢k ,s `zN tuxy£r¤aRamsey (+33/, ,**+) b3f¥¦§¨ OxCal ver.
-.+* (,**.) k Table A+.

Results of AMS +.C dating for the tephra of Kuchinoerabujima volcano.


-  19Z

20
A, 



kClm1Y;!


  ! no p qrst7? SiO, VW//.,X0,.-wt.ῌ 1 uvwxOR21

" #$%&' ()*+,(-*+(.-*+

? SiO, VW4\]^_N;! h yz/0"1 2345676*8*9:23;! {|}IH#L ? SiO,  //.,X/1.3 wt.ῌ MN

<=3>? FeO*ῌMgO @4A^. ~{*? SiO, 

0,.*X0,.- wt.ῌ 1 <BC SiO, DE Miyashiro (+31.) 5FGHF5I&; F#LMN! QRps

JK#LMN! OPQRSTUOR

t7  ? SiO,  //.0X/3.* wt.ῌ 1 

?

 SiO, VW

/3.,X0,.3 wt.ῌ 1Y;! OPQR

ZOR

[STU#LVW \]^_BCS *`abcdefgN;hi j&43C<;iBC@a SiO, 4B<

#LMN!
 