ῒΐ  /+  (,**0) 0  -/+ῌ-1+ ῕ ῔

   ,**/  +*++   ,**0  3,0  

Holocene Pyroclastic Fall Deposits along the Paciﬁc Coastal Region of Eastern Hokkaido
Ryuta FURUKAWA῍, Futoshi NANAYAMA῍
Volcanic eruptions and tsunami events in Hokkaido are mainly attributed by the subducting Paciﬁc plate.
Marsh and lagoon deposits along the Paciﬁc coast of eastern Hokkaido contain depositional records of the
Holocene large-scale tsunamis and explosive volcanic eruptions. Coring and sampling using the Geoslicer
technique at +2, sampling sites from +* areas revealed thickness of widespread pyroclastic fall deposits and extent
of the area covered by tsunami deposits. The pyroclastic fall deposits constitute mostly ﬁne volcanic ash less than- centimeter thick and are well-preserved indicating calm depositional environments. Source volcanoes and agesof the pyroclastic fall deposits are identiﬁed by the phenocryst assemblage, shape and major element compositionof glass shards, and stratigraphy. The pyroclastic fall deposits of Tarumai-a (Ta-a), Tarumai-c (Ta-c) andHokkaido-Komagatake-c, (Ko-c,) from southwestern Hokkaido, and Baitoushan-Tomakomai (B-Tm) from
northern Korea/China are abundant throughout the study area. The Usu-b (Us-b) and Tarumai-b (Ta-b)
pyroclastic fall deposits from southwestern Hokkaido can only be found in the southern part of the study area.
Most of the pyroclastic fall deposits have more extensive distributions suggesting underestimated eruptive volumes
by previous researches.
Key words : pyroclastic fall deposit, Hokkaido, Holocene, Tarumai volcano, Hokkaido-Komagatake volcano+ῌ ῐ ῎ ῑ ῏( ij$MKkl*-m!../nop

*R NOGP.)qrG %stu340v

! 2ῌ3 cm "#$%&.rwx)_1]'  JpNO(DeMets, +33,)' #$#()*+,

GP34yz {2|q}3~,(*-./01 234?=Wqq} 4B +31+ ; xB +3-- ;









56789:;0<=* +3/2 *C , 56778*C&>( ?=& Nanayama et al., ,**- ; @Awr9<q {]Wq' q

B ,*** *C' D  EFG H

:4 *&q} 56 3~;<*#$# I!?=JK "B

CM H]' >q}+33/ *C

9:L#$%GMNOGP34

=&NOG Sg7>l*34?0<R&QR&'  G S()T ]K G %&' @0<=&[+UV +31, ;* +3/2 *C' MW=

\ ]' D &8 ABg" #$#XY,*-R Cg ¡¢>( 8£D¤E.F

H(G+>(*Cwr ><G %&'I¥HZ.;[+\]^_*`abc(&d'>+efg(*NOGP34&'.,h> «-*/ῌ2/01 ¬­®¯R°±+ῌ+ῌ+ῌ1
IJ²³K´µ¶·¸¹ºyz»i,¹º¼Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, +ῌ+ῌ+ῌ1,&*, J>*¦<=§q(¨& q&' ©GB(+323) Hª (+323) &'9:L

Higashi, Tsukuba -*/ῌ2/01, Japan.
Corresponding author : Ryuta Furukawa
e-mail : furukawa-r@aist.go.jp

¤M.L¼ .

352

Fig. +. Index map of eastern Hokkaido. Surveyed regions are shown as crosses. Inset map shows tectonic setting
and surrounding volcanoes dispersed pyroclastic fall deposits to eastern Hokkaido.


  !"#$ % $"$&!}~$ %$9h&)njopJ#ENanayama et al., ,**- ; L ,**. )# ?9 f4

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$  hxy9z {|&9¯+°±²* »W %EºL +333P% z89de &»Usº <»m¼¼G20-    ,*** ,**+a, ,**+b, ,**, ,**-) E/"3< P +*   


353

 

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  (Fig.

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  G12H0E/ Fisher (+30+)  (+313)

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q l¤ e Y  D By CEu< D:; <=+,:->.?@A BC .

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D%E/§2e¨©,j (Cf)  .

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ª> \dE/u<§e¨©,ja)(3-¡¢.   £7 q63-

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bubble-wall texture (Fisher, +30-) R£¤u< D +/. HIJ \ ] ^_K

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M>N F: G1a)(OM>M`LMP

 +* S !¥­G12H0¦<:  CJ

bcQR$\d+4'>?e X SCTU>>NVW

 (NB-GS+) : §¨©®s

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G12H0R°¤u< ­ +¯.

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 ©1´($²:Pu-R<R U

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Ps

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FCC Cf e6:FCª< ­ r + S +* D%G1x

EZ)

-

 R  +**ῌ MCsdCtuvnew  x>:"G1a)(¯SR ` ¶´£··:< ­ /Ry!3 >N[R`:-R< 6G12
H0

Kz[W! AMS <{_|}:~r By ePf eG1a)(OC Ps

Cf e ­ .

­ +C¶´

 NB-GS+  _K >± £(Y1&¥G1% !: &%UD Mu< +/ cm D% ¥& ¸ 1 mm, z + mm !< 



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F

 

6: (MG-GS+) : ¸l©®¥*¡<C +*   !U  

C¹«3<¹ º // _K

 # 

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O Z[  F -S

F: 1   ,*** FJ.

 T  < ,:0P Fig.

MG-GS+ S

! 2** m ª« '", u hD1 (+333

,.0 m &'()*+,< ¬}

Fig. ,. Columnar sections of representative cores from the study area. Note the di#erent scale in Harutoriko section. Correlation of dotted (*) volcanic ash layer
is based on glass composition analysis. Sand and gravel beds are simply shown although they have various sedimentary facies (cf. Nanayama et al., +333).

354

῍ῐῒῑῌ῏῎ ῑ!pt:E;<=»W)$"¼¥ut< gOP5
 +.  Ps ,   + Cf    Pf  Ps   !"

MG-GS+ #$" , 

%



!"

,  &+7( *./ cm  %

 Pf  Ps./R.8"!"  -  Ps 

!"





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<EBj5#

Fig. - ,355 8V6Q ,!  (Fig. .a) Pf !  , + ,- cm -./ 01

 Ps 



23"456 ,758  + 

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.8"  0  -  R./ ST U //  3 '(0%  -  V5"  1 + +./ cm ),)  5#?# Ps   .

I <E# E

E@ A%&@A%'B   - : CD" (Fig. .b)+ *./+ cm E"  1 \<7ijckl (H-ῌ+1.0/ m) 

"



.'(!

 By  Pf   . Ps

 Cf   MG-GS+  0** m "E"
MG--  F , =>!"

(Fig. ,) +7( + cm  G H

E" <+7 *./ cm )I *H+JK+7 +ῌ, cm ,-=>!" ?
L5'M MG-- N$ O + '(!"PEQ  .  + R./ ST U0% V5"
EQ$ ?

῎ῌ῍ (N,0) : +WX Y/Z[1\ ++ ] Pf  Ps 

 0/-*.* y. B.P. (Beta-+.1-30) ]^-_`abI |_X H- '( 1  Pf 





. 

d$8&8  -   /   0  Ps  Te[d+8&8  , - . /  |_X)9.:; 5+'(!" f .* - +

Fig. 0 ,!  - +

, cm )I-./ 0123"4^#_Y ?5Q N,0 +WX2W

56`abc3de4f1\E" ??,-

cklg  " +- 

7ijckl 

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 SEM c ,! (Fig. /)  ,   . 

,758  / < +ῌ0 cm 7ij
 =>58 ?
#  h¡.

/<6 H7ijcklE"  + 

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Pf  Ps   !"

E"  - # Ps  !" ?# Pf  By B@ A% &@A% U0% %¦ 
5 ?L§T8.#  EPMA m ?5Q¨  ["©©§«L

C­T§«Lΐῐ῔ῒ (PK-GS+) : *ª n ¬o n®¯!

!" ?

"°±X\²p 2 ]^#_Y ?5Q v y ,**+b{ PK-GS+ pWq

)8'(!"" / ?

ῑ῏῍ (H-) : m9no2:;<=>?p@ -** m 8r ³´`µ#E" 7i

X ABpqrstCD 7u" vwxyjckl +. +322 ; zEy +333{ |_XF}G~ +  - ®¯+7 / mm )I7ij

?58 +, XH#I v

y ,**+a{ H- X:; GJ< /.3m  +3 m $.#E" XHK( +ckl=>!" ;5+

=>!"

?)8 :¶·¸'(!"  +  Ps  Cf    , m Lj5 MN5OPQ ,758

Pf  Ps E"  -  Ps  O< M H  HRSTU!"7i!"#jckl 5" 7ijckl

  . U0%¹kºs% +  1 

'B 

=>!"  + 

E"  .  Pf  By 

Table +.
Lithofacies and petrological characteristics of volcaniclastic deposits in this study.

356

῍ῐῒῑῌ῏῎ ῑTable +.

(continued)



357

klm " !

358

Fig. -. Thickness of the layer , ﬁne ash (Ko-c,) in the Kiritappu marshland. Topographic contour lines are
drawn with +* m interval and area of the marshland are shaded. Inset histogram shows frequency of layer ,thickness in the Kiritappu area.


HIJK LMNO PLNO QRSTOUV%+*   !"# ,**+b$% Kn-- &'(0 , ,0 . ,& W XY&QZ[\]A?

ῌ῏῍ῐ῎ (Kn--) :  ) 1** m *+,-./0 +1/ ,2!345678% 0 + ,&9: , cm ;<^?@ _`a& bcdc9: / mm ef *=>2+,45678% 0 , ,& Ps C2!DEFGHIJ!3 # &?@AB% Ps C2!DEFG

K Cf CDEFghUV% 0 - ,& Ps Cij Pf¨©ª«yz{¬A­-® ¯°±:²i³´µ¶

359
  .  Ps 

   /  By  Pf 

 

!"

 !#$%& ! '()*+,-./
,01

3467093,0῍῎ῑ (Tkb-*+) : 25 8:;<=>?@A-BC D
EF-G 1 FHIJKLMNO(PQ RS!T ,**,U Tkb-*+ FHVWX-YZ,
4 +[0 :C\]  +  ^_` + cm a C b"-cd(G Ps 

 "  ef./  , g[ ` , cm hi
 Ps  Pf jklm-ndop  -  Ps  Pf    .  / 

q- By  Pf 

g  "    #$%
& ./  0  Pf  Ps 
 Cf rs./ ef "    rs:#$%& ./t3)3uv

O7093῔ῒ῏ (YDN+) : wx 8:yz{A-Z|}~:-G 1 FHIJKLMN
O(PQ RS!T ,**,U YDN+ FHA,
4

2** m :FH VWX-YZ,4 +[0 :C\]  + jklm:g[ b"-cd(G Pf  By   Ps 
#$%& "    ./  , ` ,ῌ0 cm :

 Ps   - ` +cm : Pf  Ps 

 "    #$%&   './  ,  :-` / mm :\/  .  +  6:a  /  By 

 #$%&  " 
Fig. .. Occurrences of pyroclastic fall deposits in subbottom samples from Lake Harutoriko (H-). Measures for the scale are graduated in millimeter. a)
Dark brown organic silt is intervened by three volcanic ash layers in descending order : Layer - (Ta-a),only the bottom part of ﬁne ash layer is shown andthe upper part is cut by sampling interruption ; Layer. (Ko-c,) consists of normally graded ﬁne ash withcrystal rich coarse ash bottom ; Layer / (Ta-b),
composed of coarse and ﬁne pumiceous ash. b)
Normally graded layer 1 (Ko-g) lies between varved
clay. The Ko-g consists of light gray ﬁne ash richupper half and pumiceous coarse ash rich lower half.
Cracks were presumably formed at the sampling.

g'  rs./  0  Ps 

 #$%& rs./ ` - cm hY i 
G,v(G

QG ῐῌΐ (Oi-B-+) : _8:yz{A-:EF 2 FH

}~¡KLMNQ RS !

T ,**,U Oi-B-+ A,4/* m :FH ¢

- m :VWX-YZ,4 +[. :C\]  +  Ps 

 "  ef./  ,  Ps  " ' #$%& ef./ £¤:¥¦-nd§-` / mm :C\Xkj- 

360

Fig. /.

 

SEM images of glass shards in volcanic ash layers from Lake Harutoriko (H-).

 , l1 ,**-m Mb-, _%n\opqr ,** m st2/1

 -  !"#$ 

uvw ,  ,-."x yz  + %'-  . %&' + cm (){ . cm ()*+,-.

Ps 6,-789:;<=J+,-/0"1  - %2345 & Pf 6./1 @3AB@A;EF |z  , %Ps 6,-789:;<=>?1 @3AB@A'{ 2 cm () J+,-./1 Pf 6,-789:;<

CD;EF  . % - GH?IIJ+/KD=>?1 @3A1 B@A1 }$~1 LF

;EF M &NHOQR 

%'{ + cm

|

uv"

ῌ῎῍ (Mb-,) : PST UVWXYZ[\]^x  +  , % ?1 . _/`abcde;Mfgh ij-k   +  , #$

[\}(~º»k)f.¼l ^_%&

361-  ' : C + 2)C , 2s z{|}D`.7 
riS.

78y>) Cf E  ri C +2FG# C , 2#`. H
72BI cm J: KLMNO!n.4' P/k+323 ;

U +323 -dB S C + 2FG a ^_Q= AR V 

%& ATVR +32* ; V +3-- -d ~_ UVV +30/ 6 Ta-a 'W B @;<XY +1-3 <`. AZ +3/2 -Ta-adB C , 2 c, ^_%& A[\]^ +31, ; Z +3/2 -d ~_ _V+31* 6 Ko-c, 'W B @ ;< +03.
Fig. 0. Thickness distribution of ﬁne ash layer (Ta-a) in Lake Harutoriko. Bathymetric contours
are + m interval (Okazaki et al., +322).

<`. A`V +331 ; TUV +320B C - 2a'bc#,   dk7  Fig. 0  ¡H e)h + : / `. t By ' Cf 


7  fI# 7. P/k0 



+330 ;

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

^_%&.4'¢n= AgZ

U +323B S .' By 

bc£h¤i AgZ V  +32+ -d ; ~_Machida and Arai, +32- 6 B-Tm 'W B  Cf %&' ( )*+"# ,'-.

a b ^_%& AZ +3.* -d ;   !"#$ 

'/ (Table A+) ! 01 ~_ TU +30, 6 Ma-b 'W B h>¥>@234'5!6.7 44- TiO,-K,O

S.¦jk7`. 4>i ^_%& ;<89:;

(Fig. 1) 

 K, O <"#&'TiO, )+7=>?

ALarsen, +32+ ; Westgate and Evans, +312B CD@
E

)FG;H:GI:FJKLM NL
NO +P!6.'QRS. "# ,'-.
  TUV (+312) Furuta et al. (+320)
U (+33-) WUV (+331) !"V (+332) XY+31. -dB H«¬O!%&¦jk7`. an Ma-b 7 ,ῌ. cm

KL2

 B-Tm o AgZ +330B p(­)f.C - 2
2m7/k'lq!)® ¯=E2r-'(b)


4'S

.' C - 2 B-Tm ) Ma-b7«¬O!%&a -ir °sE®{g '±.4'7S. C . 2

/ Z[\ #@ ]$-^_%&`.6%&a'(b)c*-def7 ^_%&'! +,!6.'-.
S.g

6§>g +* l¨ A!"V +332 ; ©ªVmU

`. h>i j/k&'l0-

1V2mn .4'o73@p4 

5qri-.4'  6Ds778t'!6. bubble-wall texture 234

' -d 9u: riFG#`.7 tupv
<w x²« FG#^_%&'S. h 2vwx)P/k

Q A

U +322a -dB S FG c ^_%& AT
VR +32* ; V +3-- -d ~_ UVV+302 6 Ta-c 'WB @

Ta-c

;<

)h ,./ ka `® AKelseyV ,**, ; y_ +33. -j^_%& "#)dB 6Dtupv< A U +322bB C / 2;<1V2m-d n='2vwx a#   ³z{ Ay> 6D z{|} )

' .^_³%&`. 2vwxS .'a  B ?{!-. ~_ /k

 gVhViVj ^_%& ATU +30, ; Z +3.*&' "#)@ C[\. --d´µ@B)@ C Fig. ,A=gB

6§>r@S. 4>i¶·¸¹t-6l| ;.^_%&`.

362

῍ῐῒῑῌ῏῎ ῑFig. 1. Variation diagrams for TiO,-K,O contents of glass shards by microprobe analyses. Each symbol shows
mean and deviation in normalized wt.ῌ. Fields of source-known volcanic glass shards by Katsui et al.
(+312), Furuta et al. (+320), Tokui (+33-) and Fukusawa et al. (+332) are shaded in upper-left plot. A-Tn isa working standard sample analyzed in each analysis.

9:cHI¹º#*n »¼
 +322 



363

 

0={R4NOP&\I+]3 +* cm      g 

4 7894 *+s56>+],Y#?

 !" +30, #$% Ma-g

 Ma-g # 

& '

 

 f )

 *+, +/ῌ  B-Tm +],Q ( +1

E B-Tm 4B DE@Aa>E%%^( Ma-ghij!"

={#`+30, *+, 2./ ka - ,**. 



 (

rHQ

./01 2

 :  + 3456  , 7894
: ;=56 ( <# Ta-a, Ko-c, #,>?>

4NOP&BQ%(  0  Cf M4NOP
#R#$Qwy'

1%q
D

Ta-c

0(  1 789456NOP+]Qwx ^ TiO, B#Cge

#$ ". ( @ Ta-a ABC# DE Ko-c, +331 Q (  1 D={ %BC ' %( MG-2 

.* y. B.P. E/FQG0( '#*%(Figs. ,, -a) , @# F!4B  +  GHI
 Cf M4NOP&QRS"#$JKL%%( Ko-c,  . cm @# ' QT' 3 b

UVW( +32* ; X +3-- EHI

jJD0KL/ M  

4 ,**/ N ¡¢QT'D0£¤(Stuiver and Braziunas, +33-) QOP
cal. y. B.P. +s

 # 

6NOP+] '. ( Ta-b [* +001 

4 +3/2456,# ^JK + : + -&_`

( S0 MG-- 

῍, cm ./Qb` Q

789 g 9:4B;<  +31, ; Z) +3/+

Y(  W8 +31* #$% Ko-g#. ( ¥¦£¤QNRS¤Q (§(Figs. ,, -) +=# a +R) QT'DE%%0¨ Qa, c!4B

TU©V  ( ¥¦WXQªY

DEde  ( +1E MG-GS+   -  B-Tm
Ma-b _f gh"#ijDE

4B

03-*῍1*0* (  1 78945

Y(  Z) +30/ #$% Ta-b

Y(  -  B-Tm \I+],# 4NOP

 0/-*

D0 , 

(+333) # +Ko-g    0.2῍1.* ka # i « S 0 - (,**.)  0./῍0.0 ka­ D « ®S

k#l0QmnE) 10 op

# +**῍.** : +

^Z.«[¬D%( - SijDEde(. (  . 1%qrHQR& 3456 +  Cf M4NOP&QR34564'  *+stuv

NOP+]  , 789456  - 3

1nD '

 Ta-c # . (: ;=./01 2

 :  + *+s , <*+s23
#$Qwx ,>?> Ta-a *+s Ko-c, #. (  -  +  JKL%GHI"#$Qw

456F!4B ( +1E@Ta-a, Ko-c,,

Ta-b # . (  . NOP+]

B-Tm #

. (yF!4B 4C5 Cf M4NOP&QRS
%( Ko-c,  / cm @# ' Ta-b # / ' :  + GHI"#$789456 (  + @zi6{|}~ k

% D0(  , . ijDEdeD a´b< + 

#$Q '7 +3-, ; 4 +3/+ Y( #,>?> D0( W8 +31* #$% Ko-a

 # 

 (  , 789456/  -  
789 c+ tuv"

+2/0 +/D%( +1E789 a

@ uv¯\%( ^_±J`D«  deD%' QT'DE ²³. ( :  +  - ¯\+],#?
NOP_`D ]°9:4B;

 @



-

Ta-a, Ko-c,, Ta-bx; :  + F!4B  RS> 4
NOP&\I+]#X,#µD%( S0^_±J¶%'²³"0

<  +31, ; 4 +3/+ Y(  W8%+31* #$% Ko-c+

 # . ( Ko-c+ 3456+] ·/ /ῌ NOP789456

[* +2/0 

4 +3/2 Y(  - +]QCf M4NOP&QRc!4B 3456

'Ta-a #

. (  .  Ko-c, #. (  / F!4B '#. (  / @ +῍0 cm

S%

D0(  ,  3/ῌ 4NOP&( Cf M4NOP&QR'

4564NOP& Ta-a #
 A`

0

S%

3

. ( ¸B7894564NOP&t"# Ta-bijD0 Ko-c, _`DE%

op. (  - D34564NOP&

/ F!4B0 S%

¹fH¼ f364

 Ta-b 

 .

/

 B-Tm   B-Tm  !

(~6JH^H!#""  . # B-Tm $#%  / 9(;F " _H`aHb%H &'()

c^I@![ " de^Hfgh i# 0 &'*+" ,~j k96#Kl

-. Ta-c  Fm" +3-*L ~nj#i 9j(





9@96() Ko-a

:; +3,3 (;S\96 VWXE]/01023

 :  + 

.g

U

 \+





+ 

3f

A

 .  - 45 

96o9A " ()6

36##789" 36 !:969# -** km [\Tvpq9A

"##$9" %&'*()

6 [|}

*()   , &'

Ko-a #F]GHI{6J$

 Ko-a re"**+;+" <,=96>-"?@" Ta-b    - ./kst

+Oq*6J6Nm#

9A,B-C" #0D

VWX&' Ko-c+ F+2/0

L [|}@9&'"  ,  Ta-b E19A

6Cb6 3 +2/0

cuv(;Kf?@" 0D b () FG H2"

l#+ FcH2" +31/L" F]GHI{Tv6J+3-- *1 5" IH2" +31- J Us-b 3KL  6 FwH2" +323L 99x (+323)   456M7 8" F]GHI@ Ko-c+ 6JMy'+" Us-b 9 :; +00-

klNm[|}efb6C Ko-c+

 F<" +3/2

*1L  /  B-Tm #F]GHI6Jcd#"  

  0 &'9" z¡VWX&' Ko-c, #{'6J,-." Ta-c 96h" ?@¢ £¤ Ko-c, h

63

3*

 :  + 

 , =>?@ , A#|" +3 }¥5(F]GHI¦r§9

 - ?A

KN>O'BCPD

6~a¨¦ ©ªa@«¬ bA" W

" QR Ta-b

Us-b    - 

 . S96KN>O'BCTU" #VWXEYZ (Fig.
# , m [\

E@#U A*$#&' Ta-a F+1-3

L Nm@ cf5F{Tv6J  ,ῌ- cm P\9A

?@"+" ­ c*§ * 

F]GHI36J!" VWX

cf +^®|§ wU¯°-6

0)&' Ko-g #^K*  - .

_"  . `0#aa*+"##L
bA .  Ko-g  $?A

6J!" 6J#^F{#BC
VWX&' Ko-c, F+03.

L  Ta-a z#%  - VWX&'cdcf5F{Tv6J Nm@ `±#" $*()efbA* ,ῌ- cm " cf5^®|§   ghf: +

 , " &iM@ + 

 , KN>O'BC#QRPD" Ta-b

Us-b  

&icm 

²9A ³ Ta-a S?@#Xj" F]GHI ´t*µ&' Ta-b F+001

M@ +j*+*

L XJ5^6J

 XJMy'?@9" Q5F?@9*1

XJE#6JF¶ 36&iM?

klNmno" p()6J

=>?E# / cm ·¸u8

Oq96 (Fig. 2) 6JrsPQ FtRL"  ,** km 6@*6J

()#uS Tv"

#U8 36]6JcS A + F¹"

wUVx

U8#() Tv9AWy96
Qno" Xj()JYZz +{Tv6J#(96 [|}VWX,**/ ; Noda et al., ,**. *1L" 6Jº!N'

 z¡&' Ta-a _^F!
#»6J*bA#BC



365

Fig. 2. Dispersal of Holocene pyroclastic fall deposits in Hokkaido. Enclosing line shows area where pyroclastic
fall deposits are identiﬁed. Points shown as crosses are described in this study and solid squares are referredfrom literatures as follows ; Ko-a : Nemoto (+3-*), Kozu et al. (+3-,) , Ko-c+ : Yamada (+3/2), Endo et al.
(+323), Tokui (+323), Igarashi (,**,), Nakagawa et al. (,**,) ; Ta-a : Igarashi and Takahashi (+32/), Murata
et al. (+333), Miyaji et al. (,***), Shimada et al. (,***), Soeda and Akamatsu (,**+), Wada et al. (,**+),
Nishina (,**,), Hirakawa (,**,), Atwater et al. (,**.), Noda et al. (,**.), Furukawa (,**/) ; Ko-c, :Furukawa et al. (+331) ; Ta-b : Tokui (+322b) ; Us-b : Oba and Kondo (+30.), Nakamura and Hirakawa(,**,) ; Ko-d : Miyoshi et al. (+32/) ; Ma-b : Katsui (+30,) ; B-Tm : Okuno et al. (+333), Nakamura and
Hirakawa (,**.) ; Ta-c : Tokui (+322a, b), Igarashi et al. (,**+) ; Ko-f : Katsui et al. (+323) ; Ko-g : Kito andTakimoto (+333) ; Ma-g : Miyata et al. (+322) ; Ta-d : Kondo and Doi (+321). Duplicated references areomitted.

¼Py7º y366 Us-b +00-  





!"









  /X?@"$ /7(  _/,-. .L#$%

 Ma-b G#R Ma-g "'[Us-b  &!'(()*+)*+ d ,-. /0123 +31, ;  +3/+ 4
 +31* !8( Ko-d- 567

9:;%

2 

/7(%!GW,-. G#R
 h  8!0=iI$  j<=>?  @ !  (A8"uDEv( w/,-.!

!"B #C7 +323 4

$%" 

(  0=; +* km Ij,-.

'D( Ko-d

EFG$ 9H

&C (+323)

 ckl|R m n

0=i [I" [ o +32+ |I)J*(K+,-"
.L Ma-b +* /MN[w(

01 (e7 (+323)

FG Ta-a G#R)*+

B-Tm

OPQ23 G#R(! 

 Ko-c+Ko-c, !( /7(Ma-b

4 S + 5XY H 64!I"TU VWZ $ Naka-! 8!p!#I$ "

gawa et al., ,**, ; $7 ,**+ 9:;!#$0

uDE q[ ,-. !

=7!IDZ

K+



8[ Ma-b'[ 9:;

Ta-b, 9 :;,-<\$  I

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VH! <D(>  ,EWX" <F *R> U#G, J. Bandibas  <01> &YZYH$[ %I\]
J&K' <LMN*R> (^O. <P_*R>`)* "+QCa R,*,bScYῌ ῑ ῐ ῍T (+313) #, d # e fgRUV#, <h, WiTiXCH%> +.,ῌ+// e
VY
Atwater, B. F., Furukawa R., Hemphill-Haley, E., Ikeda
Y., Kashima K., Kawase K., Kelsey, H., Moore, A.,
Nanayama F., Nishimura Y., Odagiri S., Ota Y., Park S.,
Satake K., Sawai Y. and Shimokawa K. (,**.) Seventeenthcentury uplift in eastern Hokkaido, Japan. Holocene, +.,.21ῌ/*+.
DeMets, C. (+33,) Oblique convergence and deformation
along the Kuril and Japan Trenches. J. Geophys. Res., 31,+10+/ῌ+10,/.
j-"i6Z . (+31,) kl6mn:o/ pi q[0r < s*R#R \tR
]%> .3-ῌ/*..
j-"iu(vaiSwxy (+323) 
zP^-{ |}~_#, R`a 32
/*0ῌ/+*.
j-"iu(vaibcwxy (+330) 
kl6mn1:o <[0> #,$de23I4 |}~ +*..
Fisher, R. V. (+30+) Proposed classiﬁcation of volcaniclastic
sediments and rocks. Geol. Soc. America Bull., 1,, +.*3ῌ
+.+..
Fisher, R. V. (+30-) Bubble-wall texture and its signiﬁcance. J. Sed. Petrol., --, ,,.ῌ,,1.
5fg i 0. i 0 1 i h(v i ^C9:3,;iij^67 (+332) 8k

³# 

367

$8l mn LAGUNA <J#,$ (B-Tm)
4 > / //ῌ0,.
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32ῌ+*,.
t:<oixi,@yo!i(NiST?U(+331) #,, +03. 8A#
!" +1+2 ^ A#8l z#, ., ,03ῌ,13.
Furuta T., Fujioka K. and Arai F. (+320) Widespreadsubmarine tephras around Japan  petrographic andchemical properties. Marine Geology, 1,, +,/ῌ+.,.
/:H{ (,**,) <|}W sB)pi
R ~%(HC~B ,* 8@D#I d 1  +0-ῌ+03.
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 #,$1B I0<  0* J+ 1B + K ,* J + 1B 0 K V +3 p.
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P(3 i PW > (+313)  #,$1
B 0* J + 1B 
QR. (,**,) ST}W U ~
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+* 01ῌ13.
J H>ih(i¢ Hi¡£ (+333) o/>\ ¢¤ ]¥ ¦§6¨ /-. 1ῌ+2.
T (+30,) / J + B,©£^¤ ?
¤ ., p.
Ti* _¥i¦ªH§ (+312) A#A#`¨ #, ,- .+ῌ/,.
Tih, Wi(ai©W (+31/) «#,iA#i2b 9¬!C`cª«¬cª­ ­d +3. p.
Ti®f¯ei°-i,(6± (+320) «
l # f # ²gRg?t
V q#,A#h®¯³i´f <# fj> kª°r 3+ῌ++-.
TilG±'iµªH§i²-¶ (+323) #,B #,B / + : /**** !
"
Kelsey, H.i7imTniSherrod, B.i³:·
!"zP^-{Hi¸¹9 (,**,) ´µ a¶ao 2it?
t d , w ,,-ῌ,--.
§'iº# (+333) zP^!"·¸ ¹´q  deº»»¼b  p¼

368

h6%Es E

 -2 ,31ῌ-++.
    (+321)  C+    C+    
-+ ,ῌ+-.
 3  (+3-,)    !" #  !  ,.0 p.
Larsen, G. (+32+) Tephrochronology by microprobe glass
analysis. In Tephra Studies (Self, S. and Sparks, R. S. J.
eds), 3/ῌ+*,. D. Reidel Publishing Company, Holland.
(+330) $%&$%&' +*** '()*+"# )3 *+,,-./012+()*+ +*3.
-4. (+310) 56 7&8"#
 Tn /9 :;< =  .0 --3ῌ-.1.
Machida H. and Arai F. (+32-) Extensive ash falls in andaround the Sea of Japan from large late Quaternary
eruptions. J. Volcanol. Geotherm. Res., +2, +/+ῌ+0..
-4. (+33,) >+ 0?
"# @ ,10 p.
-4.1 5 (+32+) ,AB2C
"#DE)*+ =  /0,ῌ/03.
F&3456GH#7. (,***) I$%&' ,,** '(89  ./ 1/ῌ2/.
F#JK:J;<L (+322) MN=&6
&> &6&> O/  + &>?@P &>AQB 11 p.
CR7D  E#F   G  SHI  JK T(+32/) A4ULKV-MANW & O
/2A /30ῌ0*2.
P#QR !STF  PX9  5PI. YP
7UY(Z[V\. (+333) W]^_ ,/** '(`aXY  : , bZ$cde[\f+[gh`a]i )3 @jk l+ ,3 /*ῌ/+.
56Gm^_ ` (+33/) A4)3
a
56X   .* +-ῌ-+.
Nakagawa M., Ishizuka Y., Kudo T., Yoshimoto M.,
Hirose W., Ishizaki Y., Gouchi N., Katsui Y., Solovyow,
A. W., Steinberg, G. S. and Abdurakhmanov, A. I.
(,**,) Tyatya Volcano, southwestern Kuril arc : recent
eruptive activity inferred from widespread tephra. The
Island Arc, ++, ,-0ῌ,/..
5P!n6Jb (,**,) !c +00- '8 !c b)*+7&-d9 "9&e  +2 " +,-ῌ+-0.
5P!n6Jb (,**.) A4op56)
8'f )3*+  g )*+
.- +23ῌ,**.
5P!ng(36Jb (,**,) h qrBi_sEA4V-M)*+t+uj# )3
 .+ ++ῌ,,.
5# vK;$k (+331) wl Ex& m
Dnyop (Geo-slicer) & qr +*0 /3ῌ03.
s E  zt{u  |6}J  vwx  h6%E(+333) yz {|}[g ~KA~6$%&h&"AQ' $%&( +* 'wl h&eAQ)  -ῌ+1.
s E  zt{u  |6}J  h6%E  vwx(,***)  yzB*E~KA~6 + ,(  ++ 'wlh&eAQ)  +ῌ+1.
s E-zt{uh6%E
56  (,**+a) .]>5x&~KA~6$%&^_ 3*** '(E ,* yz wl  h&e 
No. + ,--ῌ,.3.
s E  vwx  -  zt{u  h6%E(,**+b)  yzB*E~KA~6$%& +ON] / a,  $cd0$%&( wl h&e  No. + ,/+ῌ,1,.
s E  vwx  C{J  -  h6%
E  zt{u  {J   z  56 (,**,)  yzB*E~KA~6$%&9"9 +OA&6
AQ NA&6 56 wl 
h&e  No. , ,*3ῌ,,,.
s Evwx#h6%EYM{Jzt{u56  (,**-) 
A40 A&6$%& +1 M3 : +O wl  h&e No. - ,31ῌ-+..
Nanayama F., Satake K., Furukawa R., Shimokawa K.,
Atwater, B. F., Shigeno K. and Yamaki S. (,**-) Unusually large earthquakes inferred from tsunami deposits
along the Kuril Trench. Nature, .,., 00*ῌ00-.
N1¡ (+3-*) 8AQ  ¢e . £  , " 1+ῌ+-3.
PJF&34H#7.P#QR56G
(,***) A4' $% 5¤/9¥E+2.- 'yz )3 -3 ./+ῌ.0*.
={ (,**,) ¦§]]+z7&yz 2
A43&>B  1- ,*/ῌ,*2.
Noda A., Tsujino T., Furukawa R. and Yoshimoto N. (,**.)
Character, provenance, and recurrence intervals of
Holocene turbidites in the Kushiro Submarine Canyon,
eastern Hokkaido forearc, Japan. Mem. Geol. Soc. Japan,/2, +,-ῌ+-/.
¡4¢£ (+30.) !c¨|©\yz  3 1/ῌ20.
Y;5.  ªC  ªIk  0A67  «¤¥H¦§J (+322) &¬&>h>8 ]
AQ@¨ ­]®d©ª`a«¬[­AQ¯ . +,ῌ/0.
U H°±4{J5PI.²4®³#´u (+333) A4 Ko-f )*+µ¯¶ +.C 'f &>q +*/ -0.ῌ-03.
z·9%£gX¸¹4C° ± (+31*) 2
K²K A4³º´¢¡ AQ
  ¨ 2Kµ¶»· AQ  ,//ῌ,20.
z·9%£gX¸Y¼z·9<J¹º»# ¼<u6£ (+31+) A4 -*6hcdaSOPxyz  +* ++1ῌ+,-.
 (+3/+)     +  +/1 p.
          !"# (+30-) $ !"#$%&'(  %&)*!
+-  +03ῌ+31.
  (+30/) '(+)*,-+,+-* ./*0  1 '(./20.13450 1
   +/ ,., p.
!"#
(+302) +,+ 1 +,./20 .134
50 1
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2"345 67 6 (+333) 789$&8:;<=3*>9?@A:;BC<=
DEFG /., -3ῌ./.
>7?H@ABCIJDAEFGHI
JK (,***) KL%MLMN)NOPF
 -3 .-3ῌ
QRSOPTUVQW ..3.
R#STXU/ (+31.)  VIYWXY"#$%&'( +.C Z 1[\ ] +.C Z (31)1 Z[\ ,2 +*+.
^7_`a (,**+)  -*]^_`bca .* +*b+1 P defg .,-ῌ.-*.
^75 6 (,**/)  -*6hcd
e`fgDihijklmTUVfnoJjklp \mn ++. 0,0ῌ0-*.
^7  5 6  2"34 TI6  qrFo'Xp4 (,**.)  -*6hcda Bq+rsq,-tsIu*!i:tj>vBw
ZoJkl$u<v1klxyzi:wxy\{xMKLyz%M|2 1 \ }
/2 0-ῌ1/.
~{ o4 (+32*) |a a .}%/0  3, p.
Stuiver, M. and Braziunas, T. F. (+33-) Modeling atmospheric +.C inﬂuences and +.C ages of marine samples to369+**** BC. Radiocarbon, -/, +-1ῌ+23.
~F (+32+) xyz ]1 y  ,0 3ῌ,-.
p (+33.) H1"<; E3 yqS
OP]
 H1
++2ῌ+,/.
X  (+322a) -a C %& .0 [\ \ } No. +2 +2,ῌ+2-.
X  (+322b) yq yq - 
1n 1  /ῌ2.
X  (+323)   +1 P 
UV Xd -* ,1ῌ--.
X  (+33-) P  3> 
T\ .OXF0 T +3.ῌ,*0.
XK  \  TI6  '¡  7F¢ X£ F¤¥o"V¦ (+331)  §¨( +330  - © ., +.+ῌ+/+.
G¡ (+3--)  ªV«67  ./0 -*+,+%&¢*!  + ..ῌ0*.
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ijan\¥<¯°¦: ±²J\J§¨©±²ª«-/ 3ῌ+2.
Westgate, J. A. and Evans, M. E. (+312) Compositionalvariability of Glacier Peak tephra and its stratigraphic
signiﬁcance. Can. J. Earth Sci., +/, +//.ῌ+/01.
(+3.*) =¢*! ./0
7[\¬\mn +. 01-ῌ1*, 1.1ῌ10,.
(+3/+) =  7
  .. +ῌ+**.

(+3/2) xy­®Iis>³yP
7¯ °  ´g 
2 +ῌ.*.
µ ±X£J²¶·¸ .+31-0 ³ 1   B  ´g¹º,-´»µ ´»¼ ·¸ ,/. p.
¶.}¹º »¼F0

370

῍ῐῒῑῌ῏῎ ῑTable A+. Major element analyses of glass shards in volcaniclastic deposits in this study.
Result for each oxide is shown as mean and deviation of normalized weight ῌ and total(*) is raw sum of analysis. N** is number of analysed glass shard.


Table A+
(continued)371