• 検索結果がありません。

北海道十勝岳火山1926年噴火大正泥流堆積物層序の再検討と古地磁気特性

N/A
N/A
Protected

Academic year: 2021

シェア "北海道十勝岳火山1926年噴火大正泥流堆積物層序の再検討と古地磁気特性"

Copied!
21
0
0

読み込み中.... (全文を見る)

全文

(1)ῒΐ  /-  (,**2)  0  +1+῍+3+ . ῕ ῔.  +3,0 

(2)   ( ˜ ™ š ,**2 H . I +0 *JK ,**2 H ++ I +* *JB. Restudy of Stratigraphy and Paleomagnetic Characteristics of Taisho Lahar Deposit Associated with the +3,0 Eruption on Tokachidake Volcano, Central Hokkaido, Japan Shimpei UESAWA῍ On May ,.th +3,0, the eruption of Tokachidake volcano, in central Hokkaido, e$ciently melted the snow pack on the hill slope, triggering the Taisho lahar which killed +.. people in the towns of Kamifurano and Biei. A geological survey and paleomagnetic and granumetric studies were conducted on the northwestern slope of Tokachidake volcano to reconstruct the sequence of the +3,0 eruption and decipher the triggering mechanism for the Taisho lahar. The Taisho lahar deposits in the proximal area of the volcano are divided into five distinct units (unit L+, L,, and A through C, from oldest to youngest). Unit L+ is an older lahar deposit that underlies the +3,0 deposits. The +3,0 sequence consists of debris avalanche deposits (unit A and C), a laminated sandy debris flow deposit (unit B), and a lahar deposit including scoria clasts (unit L,). Each unit contains hydrothermally altered rocks and clay material with more than / wt.ῌ fragments smaller than , mm in diameter. The progressive thermal demagnetization experiments show that the natural remanent magnetization (NRM) of all samples in unit A, B and C have a stable single or multi-component magnetization. The emplacement temperatures are estimated to be normal temperatures to 0,* for unit A, -** to ./* for unit B, and normal temperature to /** for unit C. On the basis of geological and paleomagnetic data and old documents, a sequence for the eruption and the mechanism of formation and emplacement of the Taisho lahar can be reconstructed. The first eruption at +, : ++ May ,.th triggered a small lahar (unit L,). Collapse of central crater at +0 : +1 May ,.th +3,0 then resulted in a debris avalanche containing highly altered hydrothermal rocks with hot temperatures ranging from -** to 0,* (unit A). The debris avalanche flowed down the slope of the volcano, bulldozing and trapping snow. Immediately following the collapse, a hot (approximately .**) hydrothermal surge (unit B) melted snow and transformed into a lahar causing significant damage and deaths in the towns downstream. Just after the generation of the lahar, another collapse occurred at the crater causing another debris avalanche (unit C). Key words : debris avalanche, emplacement temperature, lahar, remanent magnetization, Tokachidake volcano +ῌ ῐ ῎ ῑ ῏. +320 LMNO  PQRS T0 URVWX. YZ X[ RSU\]^S_ Z`ab. [ Rcd^S_ `eabfVYghijVWk. fVYlmnom epq drastuvw.  ^nomxjyz{ |xi }lV. ~RS6€ ‚ƒ„ +32/ H †‡ˆ‰Š‹ L. Œ RcdRcŽ VWURVnomxYZ. MNO  PQRS URVknomxYZ. 

(3)  (Major and New-.  ƒ ‘ ,/,*** ’^“”Vkx •–—. hall, +323).  +/0῍2//*. !"#$%&'() -῍,/῍.* *+,-,-./0123-453 67 *0*῍*2+* 89:;&; +* <= 2 >? ;@A,-,-.B-.CDE3-FG Graduate School of integrated Basic Siences, Nihon University, -῍,/῍.*, Sakura-jyosui, Setagaya-ku, Tokyo +/0῍2//*, Japan.. (Present address Department of Natural History Sciences, Graduate School of Science, Hokkaido University, N+* W2, Kita-ku, Sapporo *0*῍*2+*) Corresponding author : Shimpei Uesawa e-mail : s-uesawa@mail.sci.hokudai.ac.jp.

(4) . 172. +3,0 023456*&  . 7 Cm

(5) 089. !""#:;&$<. %6&='>?(!@ !ABCD*)*6@. !+,E-"F 9G !HI"J.1.  /01K +3,1 %BCD $02LE!. &M0 N'("90+,E-!3+#O:. 4P# !"QRST**&UV$WG.  X ,**- &Y* T!-. Z[

(6) . X ,**. ; /01K +3,1 T!BCD0. *

(7) !/56\]7^8_`90a1. bcd ! :;<= > e = 6. +.. * #f ? . Oc&. gh#30@:O iT6 N'(! 0A- I@ /ghO7"j +3,0.  08 B,k$/l!m]7 -.#O:R& /01K (+3,1). $!3nC4P!oDpqBCDH. 4P0/. I"r^8*& OW %E6  FL 2/* m+,/** m. G!$(s#H[*&Tk$  I4. Jt0

(8) 1

(9) " Cm i!d !FL. P#K!!" k*&T0bG*&UV. 2/* m ud!:;<v01

(10) ".  Lk$4PM=w MNw *i. Cm Sx!BCD

(11) y. $!"z*& i!{ Murai (+30*) }k$~ #. m]7|. ! "QRST*&*&# Murai. (+30-) #{0T"O*&  +31+ . ,ῌ ῒῐῑ῎῍῏ΐ. 345 2P ,,1** m.  2L!!3. /"Q345!RS0. 4T!URV0\,1 +t6  +3,0  +30,. 1BCD

(12) " Cm +3,0 

(13)  *.  +32223 0$#@G %6+9)W#)O.  (+31+). & %& € (,***a). CX! Cm " Cm+

(14). !=86@ (Fig. +) 345‚  :;<῍. bqT#/ƒOY

(15) 6@*& :$. Yk$34<!Z[\„]X0%6„#M . 0d !BCD

(16) "/ƒOY

(17) #^†*R. ‡! _/m!ˆ‰Š/"‹`1MŒ‡!Z/. Žalq& Cm,

(18)  /b!c"‘ k$. G!Ck$O T$!C i!’@dk. c# d“c1oD6”•D–#e—

(19) *&. $N˜ MŒ‡,f˜˜ MŒ‡˜Z˜. Cm-s

(20)  ™A”gA”!‹m0š›k$œG. +th -,-**  ! - 8!DC0ž:. Ÿ%&UV$ i"/l¡ i¢£Ij"z.  ,**1 ;  +31+. 1 Cm-d

(21) 0ž*& %& k (+333). /ƒ. Z˜345!/l ¤lm SiO,/+/3 wt.ῌ ;. OY0bG!#¥D C¦ :m7OnP"§.  ,**1 !$<k$OG opRX0. ¨T0b !!©ª"«q*& OW . rG!#H[1 T$ Uk$ 0,῍ῌ.  (+31+) ! Cm "

(22)  (Tm).   

(23)   . (,**1).   ,**1 ;  +31+ ;. * *k* T$!-. C4P#7!b¬0*. %& RX0 \bG +32223 !~

(24) . !ABCD":;&!k¬BCD!.  +30, ~

(25)  (Tk-2) +1-3 st a —d. HI"30.$k0*O iT6 %-.6. Š6 Ta-a ; 4­ +32+ +03. ®¯5 c, . tu!FL 2/* m+,/** m 0

(26) * °v Cm. Š6 Ko-c, ; 4­ +323 1**῍2** yBP !. (Tm) :&

(27) 08/56\]7^8". / pq~

(28)  (Tk-1) MN. jc& i!ˆª % -.6. /  /  M=/ -,+** yBP !. Cm

(29)  " rG !±. ²³–0™6R T%6 + !C4P0bc’. ´ ~ #* . @:&UV$R& Cm

(30) #rG!4Pp. $ +3,0 ! Cm ;  +31+ Ta-a 6. qw0bc’@:&T#.$k0Oc& %. \!µ Pm ; € ,***b :;<

(31). & Cm

(32) !+,E-"3+1&M0N'(.  - Fm-- ;  ,**1 #$ %&. "jc& $<!+,E-"3+1&M0N. 345!

(33) 08. '(")*&+,!-.  Aramaki and Aki-. !-.#@. \k. +t Ux   (,**2). moto (+3/1) 0bI¶

(34) 

(35) !·y08. Cm

(36) !¬¸FL +,*** m+,-** m 019. 6@c& i!{ z¹Iº'!{|0bG +,. !  /!01  +31+. E-!3+":$0}™0j¬T#»~0Oc& . %& d p6  Cm Sx!BCD

(37)  µ.  ,**+ ; Hoblitt and Kellogg, +313 ; McClelland and. O7:;<v!BCD

(38) !k €"¼. Druitt, +323 ; Porreca et al., ,**2 ; Saito et al., ,**- O. ½6i!\01 € ,***b.

(39)  +3,0 

(40) . Fig. +. Distribution of the +3,0 deposit of Tokachidake volcano (A), and locality map of study area (B). Numerals show locality numbers. Open square is position that the Motoyama O$ce (MO) was situated. Shadow area is lahar flowed area. Map A is modified after Tada and Tsuya (+3,1).. 173.

(41) %. 174. +3,0  3 3 # +3,0  / 3

(42) #45. 8 Cm !9"# $ %:$ ;<. =& .  //  S-P 26 +*   '7 58 & #>

(43) ! '()?58 *?+'(@. &A B,C '- Cm % (&A DE. .F/. +3,1. JK0LM# NOG + 12#3 5H  &. &A & *?+

(44) !GH , km I. +3,0  3 3$P

(45) Q&R1STUV +30, . *?+F/ 456G 7&5W 7&.

(46) STUV +32223 

(47) Q&01C STUV. 8X9':;<9' G87&A NOG. (Katsui et al, +33*) YZ & [\ +30,  STU. ,/  ,0 #

(48) !GH ,/ km A& %:;<E<. V Cm ]=;< &A^ >9? +31+.  M 7&@#ABCD_^AB)?. Cm %` YZ'a_H8Z  +3,0  3 3 =&.  E Fbcd&8'e f  gG HIe. ' +32223 

(49) Q&STUV#YZ. . h)? +3,0 

(50) iJj K& 7& 0Z   +3,1 ; )*+,-./ +3,3. - +3,0 . B-

(51)  kLMl 0Z' & , mN . +3,0 

(52) 

(53) 

(54)   . #

(55) !GH>

(56) !n7<oJpO>

(57). (+3,0)  (+3,0)  (+3,0)  (+3,1). ! qr /** m $P Qs C8 tR

(58) J=. )*+,-./ (+3,3) DE (+3,1, +3,2) eh.  u v

(59) JS u7 BT

(60) w . M'^ >9xG (+31+). yz587<Z $A C. |U} -ῌ+. {N'a_H8Z   +3,0 &8H u+

(61) !q# ~5 -*/* cm #Y  . +3,0  

(62). +3,1. +3,-  0 3  k >

(63) !#YZ%€ V6W. -ῌ.. +3,0  3 .  €uk}Z & ‚GH k X+Y" Z. +3,0  / 3 ,. [ 

(64) w ƒ\  - „3.  J†] †^%‡ _uE`ˆ M.  ‰Š‹Œ7a 3 3 2 [ +0 2 --  1.  a 2 3 V6W 12 m % +3,/.   .,0** m.  +, 3 ,- [ >

(65) !Ž >

(66) !P K

(67) !u. -bc'e &  9d‘L Le’. . k f +3,0  , 3 “g u . 3 P=. +0 2 --  .2 . . 

(68) !"# , . '7 58 u+. '

(69) h”d58 / 3 +-+. [ Ji#j•Le.  k)*+ 'l@.GH>

(70) ! 'l, m. –&. A 5H f 3 [ +/ 2 .*  —Y +* [. -ῌ,. +3,0  / ,.  + . 3 2 -1 ‚ (Y a[ +/ 2 .2  M . +3,0  / 3 ,. [ +, 2 ++  >

(71) ! (@.%. Y )*9 %&˜n9

(72) JgmA C. W™šGH'( /** m Lo"#p + mN .  ++,+ [M#—›q58 & 3 3.   +3,0 k œržŸs" Z.

(73) # / 3

(74) #458>

(75) ! '(t  . IJK0L# (Fig. +) &8 ¡<#p> *?}. G8uv4

(76) *?,  w¢ +-* m x¢ /* m. Zye£z 0[e¤ /  0 {&_ & p +. | 5  -* m } ¥4

(77) !¦H8 & . mN . +, 2. ~7m =& &8 :;<9 %&. ++  +0  S-P 26  '7 58 IJK. 0ZLe 9d‘L Le’. %:$;< &8 B, / 3 7&%&8 DE. 0L# \ §¨ € ^©¡G. +3,1 )*+C (‚ƒ —ª„ew ¡«¬. ^eG &  07& 7& J. +3,2  7GH + 3 +0 [ - 3 / [ +, 3 . [. †]­< ¡<#k †®†] Z‡J†]. w <BT w ‰Š5W DE +3,2. ˆ‰¯)? °k g& +. 2±² (— ª„eŠ 

(78) Y 7‹8X9:;<9Œ. . Cm  !.  $% &'( )*+,-./ (+3,3). .ῌ+.  (+3,1) eh. 0Z ep + mN . M l Cm 4+ R1 Cm –³ STUV 4+ .  (+3,0) 01 (+3,0)  ++ 2  (+3,0). Ž´µ¶}Z^ )*+

(79) J'(@. · 2/*.  ++ 2 ,* ' 7<Z >9? +31+ -ῌ-. +3,0  / ,.  , . +0 2 +1 }¹ p , mN Ke–&. & p , mN 9d‘L Le’  +0 2 +1. Cm . m+,/** m +3 Lo Lo ++3 '· 2/*0/* m. :;<9;< - Lo Lo ,*,, ¸’ ,, „L #º (Fig. +) k»‘#Z4+R1¼½

(80)  GH>9.

(81)  !"# +3,0 $"%&'()*+,-./012345 Table +.. 175. Correlations of stratigraphy for Cm deposit between this study and previous studies.. 6 (+31+) 7 Cm /8 9:6 (,***a) 7 Cm+Cm, ;<=> (+3,1) 7?@A'/8B() (Table +)  C* D

(82)  L+, L,, A, B, C  /

(83)  E

(84) DF GHI1J *, D KLM. 

(85)  L+, A, B, C NCO/P .

(86) 7QR S B  !TUV>WXYZ +,,1* m 1J +3 

(87)  L+, A, B, C /[\]^ _

(88).  L , 7QRS

(89)  L , `ab

(90)  A c (Fig. ,) Cd

(91) E

(92) ]8 B()HI1J ,* ,+ ;<=> (+3,1) 7@e A'/8BfgDh iK j**+

(93)  k l[\m4n]op_ .ῌ, Cm ῔ΐ῕ῌῑῒ .ῌ,ῌ+ ῐ῏῍῎ L+.

(94)  L+ YZ +,+**+,/** m qr1st

(95) 8 uv"w[]xy Hz{|D}~  €~()Dh (Fig. ,) ‚5ƒO „%* YZ +,.** m WXD†‡ˆ , m Dh ~8B '‰Š‹~MCŒ Ž8 ‘’ “”Cuv"w[/•G–8%[]4n’ —€ G[˜™š™›—œ›žœ›Ÿ #[Dh  KD¡¢C£¤]¥¦œ§›7†‡ˆ B GMHC[›¨’4nxKuv"w[/ ©Dh *xm

(96)  A  ªS 

(97)  A  .ῌ,ῌ, ῐ῏῍῎ L,.

(98)  L , 1J +3 WXYZ  +,,1* m  +,-** Fig. ,. Schematic illustrations showing distribution and cross sections of Cm deposit. On the distribution map, solid lines are *./ m isopach lines of Cm deposit and broken lines are *.+ m isopach line of unit L+. On the c-d cross section diagram of Cm deposit, central crater lava surface is normalized * m.. m, « +* m fg

(99) _* « m ¬­{|. }~ €~()Dh ‹~~D®¯ ~8B­|[];O—€

(100)  L, —   + m im°±²P7¢8ONC B ³´µ¶·¸¹]—º ¶·¸¹3»¶ M¼~8 .ῌ,ῌ- ῐ῏῍῎ A.

(101)  A YZ 2/*+,/** m

(102) _½{| ¬­{|}~ €~()Dh „%* .

(103) 176.   . m  

(104) 

(105)   (Fig. a)  !"#$%& '()*+,. --./012 34*56 7  7 -. *%8

(106) 7 9:;<=>8/.  ;<=

(107) ?@ABC DEFGDEFH I. JK+ LMNO A P.Q7 .R=S$T UNV=WXYZV[NV (Ui, +32-) \]Z^N _`abZV (Ui, +32/) 8c*+d5 - m  (Fig. .a) \ ef g=h8K+8ij* (Fig. .b) k-\l-m*Pn

(108) o *+pqr +* cm stTUNV8]NuvZVw1o$ (Fig. .d) xy *+ z +,..* m 7 pq /+* cm,. z# +-* cm ]({w!|8}$ (Fig. /) ]( {w!|7~

(109)  € p LMNO B $ ]({  7_‚O6f. * o+ xy */ z +,,,* m 7 LMNO L+ Cƒ„LMNO A P]Nuw f.  . 0

(110) 8J LMNO A 7z 2/* m †xy ,* ,+ 8‡„ (Fig. - a) ˆ‰BŠ. [‹Z‚ŒpŽ 3† 7 LMNO A 7 LMNO B C. ‘ ’*+.“”*. LMNO A 7!•–TUNVC*%LMNO B — ˜o$% (Fig. 0) LMNO A P .QT UNV7C™q šd5q7xy *+ 7 , m, xy ,+ 7 /* cm C›#0= .ῌ,ῌ. ῏῎ῌ῍ B. LMNO B 7z 2/* m  +,/** m "œ* l,-,-mB Œ J # 7 

(111)

(112) + m C0 $Ÿ

(113) +*,* cm C %0= d 

(114) xy *+ 7 D¡[¢£8 }$ (Fig. /) o+LMNO A C¤&'()*+ ,--./012 #7 

(115) 7 9:¥ ¦8Pf * 

(116)   C'§1(¨’8©ª*¥¦8«0= (Fig. 0) L MNO B 7z 2/* m †xy ,* ,+ 8‡„ (Fig. -a) ˆ‰BŠ[‹Z‚Œ. \LMNO A pŽ 3† 7 LMNO B 7 LMNO A C ‘ ’*+.“”* LMNO B Fig. -. Isopach maps of Taisho lahar of unit A,B and C. Numerals show the thickness of the deposit in meter. Broken lines show distribution limit of Cm deposit. C represents central crater.. 7LMNO A !•–TUNV—˜¬  (Fig. 0) d 

(117) ­—*+pq *./  (*.1/ mm)+  (*./ mm) ®P7 ;<=¯[° °±²³8 -ῌ ´. µijB 3°±²³%*%¶)? @A *+C3· ;<=^a[aFGDEFDEF D¸F8}$+ °±²³ *¹BD¸F º # *.+ mm 

(118) 7 »

(119). =K%½’8J. *+ ¼.

(120) 

(121)  +3,0  !"#. 177. Fig. .. Debris avalanche facies of Unit A and C. (a) A large debris avalanche block with -m in diameter in unit A. (b) A shearing joints block in unit A. (c) A percussion mark block in unit C. (d) Patchwork structure in unit A.. .ῌ,ῌ/  C. $%&'() (Fig. 0) *+,-. ,*. /012 C -34 +,***+,/** m 56,7). cm 89:;<= . + m >?="@ABCDE. FGE:H7)I J, KLJ=M) .. :HN OP2JBQJ

(122) $RE, JNSTU. -V?W , =- , m = ?X'*,YXZ. (S[\X'B]^_N=`aAbcBdE. .:ef) (Fig. -c) -OP2gh]LQJ. ij:kKC Pm : lmn ,***b. :N op JNSFGEREjij[:q. (Fig. 0) $r%=s) Cm tuvwxP-. ykK ^_N>?-

(123) -FGERE,. .$ -* cm, OP2JL=z{U()|JB=. JN}Z)$ ~-`aAbcB$qZ bcB. €v‚ƒ$%&'() z{-op JNSDE. :„* †7) €‡ˆ‰€‡ˆŠ[=M‹. REŒŽ[$<=M) W-. S ",?=-‘x’1O“”•x–—‹Sj. `aA˜™$šyLJ=v‚ƒ$%&'()^X'. :kK (Fig. .c) ›S *+/012 A /012 B. lmn (,***a)  Cm-s ,œ7)žŸ'(). : ]^¡ *=-/012 A, B ¢£7) Cm     ¤¥¦š]34 +,,** m š]?  =. / Cm 

(124) . - /012 C §?+, +322ῌ23 ¨vwxP. /ῌ+ Cm 

(125) . $%&'(). Cm  ©ª{:'X,7)S&«¬­š. .ῌ- Cm  . ®¯x°x ±²³´:Z} ©²:µ‹S . ¶ZW ,, 34 /1* m · =-[œ+. ²,- Cm - >* 2 mm >* QJ. ¸A"@X' Cm tuvwxP,œ7). š]¹ºNS 3 »:¼NS ¹ºNS»- ½›.

(126) 1234. 178. Fig. /.. Photographs and sketch of unit A, B and C at Loc. *+ (+,..* m in altitude).. 567'8"9:;<=<5 >! ?@AB. C *0  DE1F.G1H#IJKL A #M%9. #55N0 . #O @O< .  *.*0,/ mm . PQ  RSGTU" (Fig. 2) IJKL L, #V.  # . 1 *.*0,/ mm 1 #WXY. Z +./ , *+,&G[\+]&^( 9. <> . #_` a (,**/) #bcde. 0. wt.ῌ fU  0 wt.ῌ ge IJKL A. h+i+jk lmc&ne>oph+i+Vqr. #VZ ,  (*.,/ mm)  3  (*.**, mm) *+. s tuv SALD--,**S =wq&xy> z. ,&{[\+]&^( (Fig. 1)  |} +,..* m.

(127)   . . F. +,+** m ~("#€e +/ wt.ῌ F. 1 wt.ῌ.   !" 2  ##$%&'(. g("‚ƒ„" (Fig. 2) †A‡ˆ#‰Š#. IJKL L+ #VZ‹9Œ -* wt.ῌ & ! .  . wt.ῌ &ŽU KA‡ˆ#‰Š#. )*+,-!./0 *./  (+.. mm) +./  (*.-/.  , wt. ῌ ge IJKL B #VZ +./. mm) ‘F*+,&{[\+]&^( (Fig. 1) ’.  (*.-/ mm), PQ*+,&{[#9“” „.

(128) 

(129)  +3,0  !". Fig. 0.. 179. Geological columnar sections of Cm deposit. Site of each column is shown in Figure +.. # $%& +,..* m '( *+ )* +,. -. / 012 345678/9 :;*. <=>?@ AB * . wt.ῌ CDE> F-GH. IJ4

(130)  KJ4

(131)  LMJ4

(132)  0N OJ4

(133) . P-QE  AB R-STU# (Fig. 2) &. VWXY ZJ4

(134)  [\ - /9. +,*** m '( *0 )* ]^_` B *Fa]^_. ]^_` L+ ( *, *IJ4

(135) > -.ῌ KJ4

(136). ` A 6bcdefg/2<=>h@D# (Fig. 2) ]. > -.ῌ 0N -,ῌ ?cD# 0NPi 3+ῌ *O. ^_` C  j *,  (. mm)+  (, mm) +. J4

(137) kl9 m9 OJ4

(138) Pi +1ῌ *noDpq.  (*./ mm), -rst6RiuvHDwsxHyD. zq{ |}~{ }~{ }{\6€ ]^_. # AB * ,  1 wt. ῌ CDE (Fig. 1) ( *0 ). ` L , *IJ4

(139) > -+ῌ KJ4

(140) > /3ῌ 0N>. * ‚ > 01 wt.ῌ STU#. ++ῌ ) 0Nƒ 2 „>VWXY) # ]^_`. /ῌ,. Cm . Cm :; †6‡ˆ‰ŠF)‹l9. A ]^_` B *IJ4

(141) > ,0.1ῌ KJ4

(142) > .3 01vol.ῌ 0N> ,2ῌ )ŒHyŽ-. †-*( *+ ( *0 ( ,* ( ,,  Cm . ‘y’ :;“;*”/DE (Fig. 2) • Cm –. —˜?c™š/9 3 ›-E2 6‹l9œ. zžsŸ  *IJ4

(143) „g> /0ῌ  ]. *./  (*.1/ mm)+  (*./ mm)  36 /9 D¡. ^_` A ]^_` B  -*ῌ - ¢£E (Fig. 2) ]. ]^_` A ( *+ - +  (2*./ mm) . ^_` C *LMJ4

(144) > 12ῌ IJ4

(145) > +3ῌ KJ. 3-E2 + ¤:; 6¥¢9¦§ ¨D. 4

(146) > -ῌ 0N> +ῌ ) #. ”©G*ª«y¬DHl9 0¦) -** ­% 3®6R *  (+ mm)+  (*./ mm)  j>1ˆ. 0 Cm 

(147) . :; 6¯U#°8/ :;±®„g6²³. 0ῌ+ . /9 ´8-µ/2*´8±®> -** ¶·-D#?P. Cm  †6¸¹º»‡¼ ¸¹½.

(148) 180. . Fig. 2. Downstream changes of white lithic content (a), sorting (b), and clay content (c) of unit A and B deposits and distal lahar deposit originated from Cm deposit from central crater. The degree of sorting is calculated by the method of Friedman (+312).. ! "#$% &'()  *+ , Cm -./ /, 0120 +/ 345678 / 0 20 +/ 9:;<= /1 9>

(149)  ?*

(150) Cm -./. @ABC AC ,DE*FGHIJK LMN OPN,@ABC A  C Q2R*+9()  20 *+ N,@ABC A 3STUV /*  ,** mm  MW

(151) X8Y%Z[ +- \ ]^&'_`abc d%Z[ - \9 @ABC B 3ST, @ABC B eST -/ cm f 1 +*+, cm gf hi &'Ljkj 0 l<= +, \_`abcd%Z [9 @ABC C 3ST,MW

(152) X8Y%Z[  +, \9

(153)  20 *0 N, @ABC A @AB C B NMW

(154) X8Y9 0 \l <= +, 9.

(155)  M 8Y%Z[,%Z[mnBo p qr +333 s)  tZ _`abcdN. ,uvwv (,**.) Zp s)  xy z{|} Fig. 1. Grain size histograms of Cm deposit. Samples of unit L+ was taken at Loc. ++, unit A, B and C were at Loc. *+, unit L, was at Loc. +3.. ~€!Z[~‚ƒ$% , „ †‡ˆ= ‰Š‹Œ SMD-22 $%hi +*.+*++ Am, 9Ž  0ῌ, ῑῌῒῐ῎῏῍ Cm -./Z[~‚ƒ9$%|} ‘. 

(156)  //   9’

(157)   ,“” ‰Š‹Œ DEM-.

(158) 

(159)  +3,0 ῏ !"#$. 181. Fig. 3. Stereographic projections of the result of progressive thermal demagnetization experiments showing the directions of single-component, low-temperature component, and high-temperature component in the layer of unit A, B and C deposits and central crater lava. Solid and open circles are vectors projected onto lower and upper hemisphere, respectively. Triangles and Open triangles are matrix specimens. Square and oval in low-temperature component indicate mean direction and 3/ῌ confidence limit.. 20*, %ῌ&' ()!*+, mo-./01234/5. 6789:6;<=' (Table ,) )!>?, / @ῑ. AB @ῑCDE+0FGH!IJK, / nT LM;<. N - @ῑO -**-/* PQ;RSTUV%WX , @. H mo-./,(012Y!῎OZ[\]^H'_. ῑ O .** `a78bDcd;ef`TUV%WX. gh%ῒij012jῒX @ῑk(l,mno;pῒ. 0,* ;)!X'. X' g@ῑqrsῐ!] (NRM) %CDX'l p. tXu v῏w x *+ yz +,./* m 0FGH{. "N;|}()!~% /* +** ,** -** -/* .**. €‚ A 12ƒ„X' †@ῑ 3 @ῑ‡ˆ@ῑ. ./* /** /.* /2* 0,* 0/* 02*  +- |};‰=. - @ῑOŠ‹Œ% †@ῑ . @ῑO‹Œ%WX'. ' TF Ž„='!]‘‚/‹Œ,’“ 3./ K ”. Š‹Œ%•'–— +, @ ῑ 0˜&u t:6‹Œ%. ™ ῍š ,*** ›%‰='. 3œ‚ž‚Ÿ ¡0¢£‚^H :6O¤. z¥¦O§•^H!]:E¨b$%©ª ^H'_. ¤2%WAT`=' ‹Œ%WX' . @ῑ,z¥‹Œ. x +/ ;ƒ„X' / @ῑN«¬­ 0. %3œ‚ž‚Ÿ ¡0¢£‚^H¤¤2%. ˜&u|}()!Œ®%‰=' ¯Ba@ῑ,&°B. WA° ±¥‹Œ%9²0¢£‚^H³´µ1&¤. ¶·DX'Š‹Œ%WX ¯Ba:6‹Œ%3œ. ¤2%WX' (Fig. 3a, Table ,) ¯±¥‹Œ¸¨. ‚ž‚Ÿ ¡0Ÿ ^H / x¶¤¤2%WX'. !]:6,¹º »!IOW^:60Q& Aa0. (Fig. 3c) t¸¨!]:6,¹º »!IW^:. )!>?, †@ῑ¼½ ++ @ῑO 0,*0/* ;R.

(160) 182. ῌ῏῍῎. Fig. +*. Representative diagram of the result of progressive demagnetization analysis. Results of progressive alternating field demagnetization (PAFD) and progressive thermal demagnetization (PThD) are shown in orthogonal demagnetization diagrams. Intensity decay curves are on the right side of the each diagram. Solid and open circles represent projection on the horizontal and north-south vertical plane, respectively. (a) Example of single component. (b) Example of multi-component. (C) Example of aluminum-pipe sample. RT : room temperature..

(161)  !" +3,0 #!$%&'()*+

(162) ,-./0 123. 183. Table ,. Mean paleomagnetic data for Cm deposits and central crater lava (CL). N : number of specimens, Dm : Declination of between-site mean direction, Im : inclination of between-site mean direction, k : precision parameter, a3/ : radius of 3/ῌ confidence cone, R : Length of the vector.. 456789 (Fig. +*a) , : /.* ;< 0,* =. > ?@A

(163) B

(164) >C/CD89EF G@A

(165) HI@. JK;56789L CL MN - >OP /**. AQBRI@AQBST

(166) UV

(167) W89E5;X. 0/* =Y456789L. L (Fig. 3b) Z[\> , :JK;56789. *+

(168)  B ]D^_L +* 

(169) `ab cA]D^_L . >G@A8 + >RI@A. ,  : ,/* .** =Y456789 ,  : /2*0,* =Y456789L. :de=HI@AQ

(170) + @A

(171) feLghi. 0ῌ- . j89L kcA]D^_L .  >G@A89. lZmno]XPp<qLghij:eL.  + >RI@A:de=HI@AQ

(172) + @A

(173). g@A=rs;t; CL u3vg (VRM)

(174). feLghij89L w@A8xyz. {|

(175) 8}~sL€o ‚ƒZmn8„X. †‡ˆo‰Šs/ bcA kcA/Bo. L ƒZo> -1 

(176) `a *+

(177) . HI@AQ=C/CXLW89 RI@AQ=C/.  A

(178)  .   C

(179) . CD:‹;XL (Fig. 3a) HI@AQ

(180) g

(181) ŒW.  /  *0

(182)  A  B

(183) . > 

(184) ]`obcA kcA/BoST

(185) UV:.  + FŽ *+

(186)  B

(187) bcA kc. 9W/‘’“W=rXL (Fig. 3a, Table ,) Z. A

(188) MN + FŽ

(189) ”• +- 8– ƒZ. [\> 1 :JK;567[\8—˜ (Fig. +* c) ,.  ™š›œ DEM-20*+C 8

(190) mn8„XL ƒ. : /** {ž=Y456789 + : ,**. Z>Ÿ vg (NRM) 8L¡ / +* ,*. C=JK;56789L¡ 0,* =Y456789. -* .* /* 0* 1* 2* 3* +** mT

(191) ++ ‚=„XL. L. ‚ƒZmn8„XL¢£ q<

(192) >OP. *+

(193)  C ]D^_L 

(194) `a 1 . / mT ]D$˜ 8BŽ =rs/8}~. :?@A8 / :G@A89L q<

(195) W@. L CL lZmno]D , @A¤b

(196) ghij. A8xyz †‡ˆbo‰Šs/ ?@. :~€<qL oŽP> Fq

(197) @ABeL. A

(198) B

(199) >C/CD89EF G@A

(200) B

(201) >HI@A. ghij:~€<qL (Fig. +*) 

(202) /;< . Q=¥¦§C/CXLW89 RI@AQ=C/. q<

(203) ghij>lvg (TRM) /P¨pE. CXLW89E5;XL HI@AQ

(204) ŒW>¥. qLghij=rs/:}~EqL (Fig. +*) 5. ¦§]C/CD89L (Fig. 3a, Table ,) Z[\. © Aª « 1 = / mT

(205) ‚=Z¬sde. > 2 : /2*0,* {ž=Y456789 (Fig.. 5ghij8­® :~€<qL (Fig. +*b). +*b) - : .**/2* =$˜¯67 + :. 0ῌ. 

(206) . ,**-** =Y456789L. ‚lZmn

(207) °¡|l«o3±)

(208) N

(209) . kQ

(210) ²R +,+** m

(211) *0 o©³s  A. 8}~sL€

(212) 8„XL o. ]D^_L 

(213) `a / >?@A + >G@. >lZ8„XL // 

(214) `a *0

(215) +, 8–. A89L xyz †‡ˆb=> ?@A

(216).   Bartington  MS,B-Susceptibility. B

(217) >C/CD89EF G@A

(218) HI@AQB RI. meter 8

(219) L SI ?´= w‚= + oŽ˜ /. @AQBST

(220) UV

(221) W@A89E5;XL Z. µ ¶

(222) Œ·8¸¹L. [\>OP

(223) oŽP /2*0,* =Y456. ‚lZmn

(224) °¡K|l«o©³s3±)

(225). 789L  B => 0 « / :?@A. N

(226) 8}~sL€

(227) 8„XL ºj. + :G@A89L xyz †‡ˆb=. z»¼‰ >:„½5L€ *0.

(228) 184. '

(229) ( Deviation) ) +/* +, -. +333. / 01 / mT  12,3  1456789:  (VRM) 1 ; < );  6789=,>5?@ ==, A ,**+ B'CD5EF1G,HIJ8KC%& L KM NOKC EPQR Table - LS

(230)  5K EPQ:TUL%&,=VW!$  1 %& (DRM) VL$ :? / X ) -/*. Y1Z[5\] S

(231) Q). ^_

(232)  @CD5Q!L:`abcR) -,* 1,d,d"Pe#1fg

(233) $%h (Pyrrhotite) ij< )Sk#$ !l ,**. m, Q NP:no5!pqr&N1 @$!6789: Fig. ++. Variation diagrams showing change in magnetic susceptibility during PThD. All specimens are taken at Loc. *0.. A!pqr&NQ='(L)s1tuv_*w x+y S

(234) @= ! &NLi/$ $%h: ,z-5"PLC{>|#$*1:5?=VW! $  !pqr&N: / Q}>))s S, @$.  +, QL~?> tu +** =L€.. !QR: /2* 0,* 1 ‚ ƒ. „{ ‚ t= †QL~?>€.L/. 6789:tuv_*wx+y S,/=/3*. 0{":5‡ ˆ‰!1  !LNŠ. C?@=. Q!Li/$  h "P:|‹>?5?=1. ,=VW!$ . ! !pqr&N: /2* 0,* B'1. Cm %& DŒŽ8 A :'2 *3 *+ 1. #$ (Fig. ++). :  „{NŠQ +- QDŒ 3 Q=EP. 0ῌ/ 

(235) .  =Q‘"P#=. Q - Q)’R1,@= S, NŠQ . Q. “” 4• L +–,NŠ‘"P—. ) -/*0,* 1,=VW!$  / ˜. 5™1š›, / L6, ŠE)ƒP5œ. 2 *3 *0 1: 0 Q}>)’R1,=VW. S,ž7ŠLŸ[; * no } L:no1. !$  Ž8 B :'2 *3 *+ 1: EPQ. ; )ž7Š)89,>? * ¡"P s2ŠE. 3 Q)?¢$* -**./* 1,=VW!$. 2£:f)89,>? * !"P } L;8. <¤-ƒP5R= ¥~$m{=VW!$ . L"P)>,?* —"P ŠE} s2. / ˜2 *3 *0 1: 0 Q}>)’R1. ¦‘2); * ‘ = / ~L6,. ,=VW!$  Ž8 C :'2 *3 *+ 1.   „{NŠ+§ ., QDŒ no ) / Q ‘ ) - Q ¡"P ) ++ Q. +, Q! 1 Q)’R1,=VW!$ / Q. ) -/*/** 1,=VW!$ .  !"P ) +3 Q —"P ) . Q1;{. ¨ (,**-) :©?@ª (+3,1) *P«LE¬?. ‚DŒ ) ,  ¥~*: —". >­*‰®-¯A „{ B°±=¨ (,**-) . P ) + Q !"P ) 0 Q ¡"P ) - Q. <¤

(236) = *3 *+ HQ=¨ (,**-) C². 1 no :  ‡ < ¤ -" P,Q  )©. !+–,Q *3 *0 HQ=DszE. {. (Table -). !+. –,Q)‚$³$´µ

(237) =VW!$  *3 *+. 0ῌ0 Cm   . Q L: ,   ¥~Q ) F ¶^_, ‚$!:.   !"#$ Cm %& . -/*0,* 1, )s*:}>’R1. R:A (,**+) L·{ 5K  !. ,=VW!$  @: C ²   R  .  

(238)  Kirchvink. /2* B ' = ,  ¨  (,**-) = ¸ 5  s + ¨ . (+32*) LC ¹G ?> X )Hº,. (,**-) )DszE: ,  *~Q)^_

(239) =. > - B' »Z¼½ (MAD ; Maximum Angular. ,@=:*3 *0 =sI

(240)  , , *3 *0 JR.

(241)  +3,0 

(242) . 185.

(243) . 186. 

(244)   

(245)  .   !"#$%. ,,*.,* $&'() (,**-) &*+(. ,-&./0,( 12 (,**+) 34 ,., ka 356 . 1  1ῌ+. . 7+38 4 !". Cm 

(246). 9#$4 %, 4 %: ;<. Cm &'(=8>?@A L +  )BC(>. D+E, *FD+E, +,&./ &. ?@A A, >?@A B, >?@A C &*+ -G3H. '(IJ,&./FK$+,;< LM. 0NO&./0,(PQRQ12 S132S1T4. D+E,&'($U(&./0,( >?@A A -. 4VWX5YZ67[LMJ& B&'. 8 '(\]^9C:  I&I&4 !"8 . (20;,(_< +3,0 = + `>?+$+. @ ab2 4 2ABcd,C. ,ID6J&20 +3,0 =e+,. E2,f,&./0,( d .g[>. &'&'($U(&./0,( FGHIJ. ?@A A KLU(M */ $  >?@A. ; 3** m 20FGHNd$'(O ,** =h. L+ &>?@A A ij"$kP(Q"l[.  mR ,***b   >?@A L, &./ 2. J, Cno(STpD+E, CB. U1qVZ6+ -G3H0&WrPQRQ1. csE2@+, J@>?@A A &>. LX2 S132S1T47[LM J,01. ?@A L+ ij,tkP(Qupv. >?@A L , A  C  1&wxY-0,+6 d. y&;$(.  >?@A L+ & Ta-a &Z[\z{| ]^$U.   >?@A A } a_vy20~Q. (I Z>?@A A &Z6+t€. `<$U(J&B1 za=8 1 ‚`<$. 

(247) '&'(Y-0,+6J&20 >?@A L+ &. 6(J&20 b & `<$Up&./. h 1ƒ.\c$U(&;, de .&. 0,( d „z>?@A L+  cw$6(J. '($U(†fg;6. & CUp"$ ‡9p; ,* m z. >?@A A, C  ˆ‰Š‹R@‹ +h Œ. Ci[p6 7jkŽ +3,1 &6=l. @‹B@mQŒ@‹]‘Q~Q-Ld. U(J&20 >?@A A C"E2. ,6(J&20 D+E,&„&./0. I „’1&wxCE2n. ,( <n >?@A A, C  o<$. oEo&./0,(. . & -/*0,* $. “ 6(. >?@A B ”"$ p•qr[ s62. J&2( J,0C'(tu+0  v+. –R—˜C:Y-0,(J& dwx>?@A. 20@mQyo5 z;<$&.. A &p™v+6J&20 +,{| š}$~D. /0,( 1xmQn66›U(  . +œ“)$Up&./0,( d  „. +3,0 =3$€34žVW34 +‚G6. ƒp„\ +)Ÿmb'(J&20 `J;"$. PQRQ1LX2 S132S1T4$U( 7j. @FMR Š¡&„&./0,( C(. kŽ +3,1 p >?@A A, >?@A C C'. 1&wx@mQ†$U(J&20@mQ. ( mQ6[ +‚¢61Q†$U(J&. yo£i 20¤¥,&./0,( &'<. 20 +3,0 =3$€Q $ +6 JJ. n  3H20O /** m ,J; +,..* m $ -**. &20 ;<$ 3H‡"¦84 . ./* $ J; +,+** m „"$o<&+p J. $%, J,ˆ:,. ,O&  -ῌ nLd,(p•‰Š+¨. &+§. ‹ &'I&./0,( +32/ =Œ© 0,῍. ª«¬./0,( J,Q(Q$U(&'(l. ῌ3H$Ž­a<n ”; .,3. ® ‘6 &/Q(Q$Up&Ib . ‘ ,.3.2 $Up ’“R +323 J! .,3. ”•=Eo”$ +6 p –—+O&. &6=˜ ¯`1 a°±™š0,>?@. >?@A A &./%,;<†@›. A A >?@A C -;< ‘<n (..+). a+x./0,( J,0J&.œ'(& >. &"6˜$U( d ž² (+323)  +323 =. ?@A B  „ @ ³ hydrothermal system ; ´. 0,῍ῌ3H20µB34¶¨Ÿ~·[„;. , +330 ¸¹º%»,. <n ./* $U(J&&I ¡+6 ". 4 %:ƒp?+¢£ -**./* 3. 0,* &¤o;<%,6( J, 3Z. ¼(&@@›a“½¥9¦, §$.

(248)  

(249)  +3,0

(250)

(251) . 187.     !"# $. %& '( +** m,  /** m )!*. + ,-!."/0#$1(2#3). 4%&%&'.5# 3" (%)6. 7* 89),-!.*:;<=)%>. ?+@.AB,("+9# -./C +3,1 3. DEF"# 3"G (,**0) 0H7I) -. "F31D1H# (%23J

(252) K),). LM("45.6N+9OM)7P+. 7Q4A8( +** m R.S9T+9DE. :;)> U<=>?@.(%H#. F"# +3,0 / V ,. A +, W ++ BXY 3A + Z. 

(253)  (pyroclastic density current ; Valentine and. C:5P 3:)7P+;<=. Fisher, +33-) )D[H#".5#DEF"# 3.  3;<=E\:F ?GH I]1". ':Q".5#3^F $1#^. E\:F_J1K% L:F ?M`:F I. NOQab.5#DEF"#. ]R.",P -./C +3,1 ^ ;<. cdef L, N)g&%&MP hPiQ. =RS-4j9T)kP+"l -./. mnoPpqrs^FQ* itQ8"iUuF. C +3,1 Vv;Ww7Q^P 3 + ZC:. "Q93^F ;<=DEF"# R. .;<=_Jcdef L, +.  3J

(254) KXYZ[\]x7*X /** m . +9#DEF"#. ^ + ZC:5P_I] y` +3,0 ; -.. +3,0 / V ,. A +0 W +1 B 3A , ZC:). /C +3,1 ; ab +3,0 )BcH#3^F +3,0 /. 7* 3 J

(255) K XdB  ( % oU \e . V^ + ZC:.;<=)UfH. (Fig. +,b) oU\P9Igz-h5# iE. #DEF"#. { +0 W ,* BXYjk|9I}l7IQ:~. \3^F +3,0  (Cm) _€(". 1m9+Hn‚)onp qr1ƒoU. +9I„ cdef L+  ,** 2 . s„\#1tl †AQ4uv ‡w.  cdef L ,  +3,0 / V ,. A^ + ZC

(256). x1yP+9P 9Iz' +,+** m I])5PG. W cdef A C  +3,0 / V ,. A^ ,. ‡wx)9+^YIˆ+{|.‰}gz  . ZC

(257) WDEF"#. ~Š‹Œ +3,3 5# $5PJB. . Cm Ž;<= ;‘uF"#’. “)kP+'( ,* m $€1”P+93• -. &)–.5* )–;<=+,. ./C +3,1 cdef A cdef L+ 1—*˜™. DEF"# 33^F Cm Ž;<=. .9#3^F

(258) )‚9itQ8"ƒ. cdef B +$1. $1š›#^ 3"1„9#^QF,c. #^ cdef A 1—*3œQF  †}. def A +DEF"# $6 (%). ž+&‡("DEF"# 3",ˆ1)‰. Ÿ‰Š‰ p': (-** ./* ) . uP;<=‹Œ("# R R;<=g7. ,cdef B +DEF"#. *’Q &3)¡R"#Ž¢ž +/.1 wt.ῌ .5. oPUs„ 5^A

(259) U£)1,*+. #l  (Cohesive) ;<= (Crandell, +31+). 4#7I)uE †AQ4¤3I¥^F¦P. )BD("# ;<= %&. A"+‰ 3"MU1\§+9 9I ,. S(%H#3)7P+H#DEF"+9#;. ZC:~+9#¨3) + , ‘}r1u. <=. _’)g7*’Q &3)¡R"#Ž. +9“z .3© +3,0 • 3‰ :~. ¢ž - / wt.ῌ \;<=31zI Capra. ‰ 3J

(260) KN

(261) K$XZ[^F'4oU. and Macias, ,**, ; Lecointre et al, ,**, Qª. \e «¬9+^ + ZC:)7P+$Xr. 1ῌ,. +3,0  /  ,. 

(262) . )ˆ”:x5*. 9P$I•­Q–UZ\. . r)—p $˜™®1Q+¯P+T1š›. \3fWC°gz1œRE+ ,) +3,0.

(263) ‹µ

(264) ¶·=10H (%23J

(265) K

(266) KI].¸¹¸^F)7P.  3–U±žCŸ1²P+9 ³1´E )2 ) v ‰

(267) ‰Q ¡ ) % !P+99I ab +3,0 QªC°gz U7IQ¢45. +£(" JB;)':.5PA¤S+. "310º+9# cdef B c. :'4Q^P‹Œ("# (Fig. +,a)

(268) K). def A š›*¥*˜™8*$1»¦). *.*+2 +*0 *.*+/ +*0 m- §9T+9 y`. #^ cdef A 1—*˜œžQF +. +3,0 ; ab +3,0 R ?T¼½.‰#3J

(269) K(. ,1&‡DEF"# (Fig. +,c) cde.

(270) 188. ῌ῏῍῎. Fig. +,. Schematic illustrations showing the formation process of the Cm deposit. (a) Central crater before the +3,0 eruption. (b) First collapse of central crater at +0 : +1 May ,. +3,0 (unit A). (c) Large explosion and hydrothermal surge melting snow and generation of lahar at downstream (unit B). (d) Second collapse of central crater just after the formation of unit B (unit C) and magmatic eruption producing volcanic bombs at the central crater..

(271) 

(272)   +3,0 

(273)   C . 189. . (,) 

(274) !" #$% A, #$% C. &'

(275) '()*+, (Fig. +,d) -.". /01+

(276)  #$% B  !234

(277) 5. "#'6!$%7 (+3,0) &8 '9(:. 6;<=3>

(278)  #$% L + #$% L , <.  +?@ A,BC* , D +E)F'. =3>

(279) A, B+*

(280) GHI. ?J,* '9(J!( KL

(281) '?J,#$%. !+,E!MN-O;./E0PQR .1<.  C (2S*. =3>VW+,. 3T45U-,C*A. , X 0$6Y (+3,1).  7Z8 . (-) [C* 9\: +,..* m 5J?. V'  B#$% A #$% C ]JE. #$% A  ; ^ <  = ^  0,* #$% B . >'?J,-+_ ?@5U-,()*+, Z. -**./* #$% C =^/** ()*+,. A #$% C. +3,0  3 `BCD?CE'. (.). /FGaHC* #$% L +  +3,0. b  cd +3,1 Ie-,-,fJI'?. g"

(282) '?J<=3>

(283) ()*+.  #$% C. , /Fh;^<C* #$% A  +3,0  /. /01+KEL'?J,I. ' 3 `iBBCED?JJB #. ` ,. 7 , jMBC6?'/01+

(284). $% C Gk 3 `iBb Gk. Al #$% B D?CE'\^. m,BC*NW+, 3 `CE'b 

(285) . !!O nU'P QR +A, !23. ojSpqT@C +3,0  / ` ,.. 4. WX 0$6Y +3,1 E4'?ZY. A, #$% C #$% A B rH&C. sZ[\' (Fig. +,d). E'/01+

(286) A, #$% L, #$. g]6! +3,0  / `g"^0_  ! QX+?JfJ \P B !VU! t kauEb) Cm iv<=3>

(287)  ErH'fJ \J  ErH-,. !234 UEVC'?CE'<=3>

(288).  A  C /F. m,BG6l +3,0  / `. ,. W7 + jMBC`CE'<=3>

(289) . A,()*+, (/). +3,0     U E V C' #. w cd  !_ DJ? $% 7 (+3,0) ef. $% B E

(290) Wx. !234O;<=3>A,. (+3,0) gh (+30/) ijk (+31+) l$ (+33-) I. ()*+, B+*. #$% A EylBRnzl. {| Al B+*{|VU!h}! ~j!. UJ t mauEES<=3>ECEWx. En'U.x1Mt kEop r. ()*+,. H@JJ!qr* stW+?J, oj{| 6l0_ ! :4' B+ . ῑ. ErH-,]d!vfJ \JB. u{|EXw,Al Wu[vw[€. x*C B‚ijk (+31+). VU. v'?A‡% 4W+ !Oˆ‰56 ; ! ‚Lh ef (+3,0). C* rH. ῐ. ƒy[z„s{J1@ †|}~€ vdŠEHJ1@L‹ŒŽEJ1J Wu[vw[[Eƒ%„ †‡<ˆE‰. ^Š‹'?Jt! Œd^'. Ž?J1J Wu[vw[[E‘. ’E rH ! ‘b'-,*“”-. •† ˆh2Ž’“Ž”A–E„ƒ. , 1'  rH‘b' !__•. )J1@ –—˜ † %g™š† ›~œ† . o&—rA,. žd˜w›† ™g‘ ›† $šŸ›† ›]œ  † KSpTyh2Ž’“Ž”žŸE‰. 2ῌ ῎ ῍ ῏. Ž?J1J  Ÿ¡U{|¢¡¢~. 

(291)  l£¤5M,,SpO;.  .1<=3>DJ? ¥$¦§~/0. ˆ6, Cm

(292)   ‡<  aH¨H. 1+a©DJ?„ƒ)J1J ª£¤« ¥ . *;2

(293) ;^<¬C* +3,0 . ­®¦¯† §/¤«°¨¡U{|¢©ª«w¤«{|. ¬¬O; CEªaDJ?gt* x*C. ­Ž®3¯° ~ 

(294) [%j±²ƒy. . ™uœ³±ƒ d²³†L‹´€h±8EJ. (+). Cm ijk +31+ O; Cm+ ´k. 1@ –µµ¶·ƒy€v¸¹º¶E'?J. ,***a µW+^£¤G-,

(295) . 1J ·3¸<Ž¹[ D.M. Gravley ~. #$% L+ L, A B C V@,. Abstract Eº '?J1J h»SpT¼½».

(296) . 190. 

(297)    - !"#$.%&/"01'2()3 =>.-?/@ABC 0D1 EF 89GHI:;< JK=>89? MENAOPQBR CSTCUV W?BXD ?-8 ῌ ῏ ῎ ῍ Aramaki, S. and Akimoto, S. (+3/1) Temperature estimation of pyroclastic deposit by natural remnent magnetism. Amer. J. Sci., ,//, 0+3ῌ0,1. Capra, L. and Macias, J.L. (,**,) The cohesive Naranjo debris-flow derived from the Pleistocene debris-avalanche deposit of Nevado de Colima Volcano (Mexico). J. Volcanol. Geotherm. Res., ++1, ,+-ῌ,-/. Crandell, D.R. (+31+) Postglacial lahars from Mount Rainier Volcano, Washington. U.S. Geol. Surv. Prof. Pap., 011, 1/p. Friedman, G.M. and Sanders, J.E. (+312) Principles of sedimentology. New York : Wiley, 13,p. YZ]k[lmN\: (,**+) ,n]^_] ^.`@opab,  , ,ka +, ,  .0 . +21ῌ,*-. Yqcderkfgh:Ni j (,**1) J ^Kes, ka,  - -** *t+,l ,  /, / ,/-ῌ,1+. tcNyuv (+323) ka 0,ῌ+ ,z, {+ x@ +322 *ka, +,y} z~DPK g‚ƒ789 ,-<:;2 (No. 0-++/*/.) 756:;@L 5€:; (+) „ :;‚ No. B-0--/ ƒ„9 :   01ῌ12. Hoblitt, R.P. and Kellogg, K.S. (+313) Emplacement temperatures of unsorted and unstratifaied deposits of volcanic rock debris as determined by paleomagnetic techniques. Geol. Soc. Am. Bull., 3*, 0--ῌ0.,. c†  ‡ˆ‰ xŠ\‹ ŒY‰ iŽ  (+333) ]^_@opka ‘’z~  8 Qg“ -2 †:;„g‡ˆ” •n:‰ %xqs (+31+) ka , L+,lŠ–‹ŒDPK—5˜™ J^ K—5g +-0p. ŽYš (,**-) ka‘’"',z“@”•, Š–l˜4™~šT˜›789:; J^K  hT:;<;<

(298)  ,.3 p. ŽYš  ¡  [pT: f ¢¡  qp£ ¦§E¥; (,**.) ¨ ¦, ‘’z§¨©ª « k a +3,0 * , ‘’  ¨ ª ¬P9$­ !1¯  ­B, g ,**. *`®° g‡ˆvR ” p. -0. •n: (+32+) ²r Š–l +Q_ DPK Disaster Map 456´± ,-<:; 2345656:;@L3456<„:;‚¶µ ¤

(299) +,565L4 Hazard Map ·@DPK¸V P9+,56v»:; ƒ„9 : ½¼ ½  3ῌ +-..          (+320)  !"#$%&'  ()  )*+,  +32/ *+,456789:; ,-< :;2 (No. 0**,**/*) 345656:;756: ;@L No. B-0*-1. EY:FZGH[\]I (+323) J^ K_`a, LM L 2 p. Katsui, Y., Kawachi, S., Kondo, Y., Ikeda, Y., Nakagawa, M., Gotoh, Y. and Yamagishi, H. (+33*) The +322ῌ+323 Explosive Eruption of Tokatidake, Central Hokkaido, Its Sequence and Mode. Bull. Volcanol. Soc. Japan., -/, +++ῌ +,3. Kirschvink, J.L. (+32*) The least-squares line and plane and the analysis of paleomagnetic data. Geophys. J. Roy. Astron. Soc., 0,, 033ῌ1+3. NbcO (+333) dPe f QRg ,.2p. STh (,***) PeM UiM ,*** * *V S ThjWX B+-No. -/. Lecointre, J.A., Neall, V.E., Wallace, R.C. and Prebble, W. M. (,**,) The //-to 0* ka Te Whaiau formation : a catastrophic, avalanche-indeed, cohesive debris-flow deposit from Proto-Tongariro Volcano, New Zealand. Bull. Volcanol., 0-, /*3ῌ/,/. Major, J. J. and Newhall, C.G. (+323) Snow and ice perturbation during historical volcanic eruptions and the formation of lahars and floods. A global review. Bull. Volcanol., /,, +ῌ,1. imCuvwnopqHrp xq s pe : (+323) kaDA9 +322 * +, |w9+,r€{|}~ +322 *ka, +,y } z~DPKg‚ƒ789 , - <:; 2 (No. 0-++/*/.) 7 56  :; @ L 5€:; (+) „:;‚ No. B-0--/ ƒ„9 :   01ῌ12. McClelland, E.A. and Druitt, T.H. (+323) Palaeomagnetic estimateres of emplacement temperatures of pyroclastic deposition Santrorini, Greece. Bull. Volcanol., /+, +0ῌ,1. Murai, I. (+30*) On the Mud-flows of the +3,0 Eruption of Volcano Tokachi-dake, Central Hokkaido, Japan. Bull. Earthq. Res. Inst., -2, //ῌ1*. Murai, I. (+30-) A brief note on the eruption of the Tokachi-dake volcano of June ,3 and -*, +30,. Bull. Earthq. Res. Inst., .+, +2/ῌ,*2. ›[ (+30/) kaS•’–B œ—— /3 +.ῌ,-. ežŸ (,**.) œ!œ+žŸ •Pe   P¢dPe@o AMS -¤ £¤ -. ¥ ©:;g +12p. «ˆš ‡ˆ‰  ]qp£¦®Y‰¬ p ¢ (,**2) ka¯[DA9, ‘’ z°789:; ——g± 0* / ,-ῌ-*. op³H (+33-) ka ‘’–B ,-< :;2345656:; :;²³

(300) , 56´µ 45· ƒ„9 ¶¸¹ ¶µ¤ 31ῌ33. ¹qºc (+3,1) kaº» ¼`  -3 ,*.ῌ,+-. ¹qºc (+3,2) ka  .* -0/ῌ-00..

(301)  +3,0  !"#$%&' () *+, -./ 01 2 3/ ?@AB (,**/) CD

(302) EF GHI0JKL NO ,**.  3 P ,- QRSTUVW `

(303)  /* 0 /-/ῌ//.. Porreca, M., Mattei, M., MacNiocaill, C., Giordano, G., McCelelland, E. and Funiciello, R. (,**2) Paleomagnetic evidence for low temperature emplacement of the phreatomagmatic Peperino Albano ignimbrite (Colli Albani volcano, Central Italy). Bull. Volcanol., 1*, 211ῌ23-. Satio, T., Ishikawa, N. and Kamata, H. (,**-) Identification of magnetic minerals carrying NRM in pyroclasticflow deposits. J. Volcanol. Geotherm. Res., +,0, +,1ῌ+.,. mnE op qr s (,***a)  V YtuvwxyH

(304) J z {|}~!"

(305)  -3 €Q‚ƒ ]:„Y ] †D

(306) mnE Ž op (,***b)  R’“”•– a UV (+1-3) —U˜™ š›œ

(307) Q ] ,*** Ÿ ] †!¡D +//. ªn"« (+3,0) XY‰Š

(308) l‰Š‘ 3/ +ῌ,0. °@± ²³´% (+3,1) XY

(309) µ:& , .3ῌ2.. @º»¼Ž (+3,0) XY½

(310) _ 00p.. 191. 456 (+330) 78

(311) 9: ;< => . M p. 320. XYZ[\] (+3,3) XYZ^

(312) _ /,+p. ab cd (,**.) ef@ghijW #$%k'

(313) l ++* 1 -2.ῌ-3.. Ui, T. (+32-) Volcanic dry avalanche deposits  identification and comparison with nonvolcanic debris stream deposits. J. Volcanol. Geotherm. Res., +2, +-/ῌ+/*. Ui, T. (+32/) Debris avalanche deposits associated with volcanic activity. Proc. IV International Conference and Field Workshop on Landslides, Tokyo, .*/ῌ.+*. Valentine, G.A. and Fisher, R.V. (+33-) Glowing avalanches : new research on volcanic density currents. Science, ,/3, ++-*ῌ++-+. ‡ˆ (+3,0) XY‰Š

(314) ‹ Œ ‘ - 11ῌ3.. ‡žŽ (+3,0) 

(315)  -2 /+-. ¢£¤ (,**0) ¥¦§ ghij¨|©W #J : ¬ S, $ ­® ¯  !"

(316)  /+ . ,/1ῌ,1+.  D¶· ¸ ¹.

(317)

参照

関連したドキュメント

②藤橋 40 は中位段丘面(約 12~13 万年前) の下に堆積していることから約 13 万年前 の火山灰. ③したがって、藤橋

を基に設定するが,敷地で最大層厚 35cm が確認されていることも踏まえ,堆積量評価結果

敷地と火山の 距離から,溶 岩流が発電所 に影響を及ぼ す可能性はな

敷地と火山の 距離から,溶 岩流が発電所 に影響を及ぼ す可能性はな

敷地と火山の 距離から,溶 岩流が発電所 に影響を及ぼ す可能性はな

敷地からの距離 約48km 火山の形式・タイプ 成層火山..

敷地からの距離 約66km 火山の形式・タイプ 複成火山.. 活動年代

敷地からの距離 約82km 火山の形式・タイプ 成層火山. 活動年代