桜島火山大正噴火の噴火様式とその時間変化

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(3) ,**0 + ,- ,**1 . +- . Eruptive Style and its Temporal Variation through the +3+.῍+3+/ Eruption of Sakurajima Volcano, Southern Kyushu, Japan Maya YASUI῍, Masaki TAKAHASHI῍, Kazuhiro ISHIHARA῍῍ and Daisuke MIKI῍῍ The +3+.῍+3+/ Sakurajima eruption was the largest eruption in Japan in the ,*th century and erupted andesitic magma was about +./ km- DRE (Dense Rock Equivalent) in volume. Pumice fall and lava flows were generated from the fissure vents on the western and the eastern flanks of the volcano and pyroclastic cones were formed around the vents. Eruptive style changed with time. It is divided into three stages. After the initial, vigorous, Plinian eruption of about -0 hours (Stage +), extrusion of lava associated with intermittent ash-emitting eruptions with or without detonations lasted for about ,* days on both sides (Stage ,), followed by an outflow of lava for more than +./ years on the eastern side (Stage -). Consequently, the vast lava fields, which consist of a number of flow units formed on both sides of the volcano. Some units of lava show evidence of welded pyroclastic origin, suggesting clastogenic lava. In the western lava field, surface blocks characteristically consist of pyroclastic materials which show variable degrees of welding even within a single block. Typical eutaxitic textures and abundant broken crystals are also recognized under the microscope. Some flow units can be traced upstream to a pyroclastic cone. These features indicate that many flow units of lava on the western flank are clastogenic, which were generated by the initial, Plinian eruption of Stage +. In the eastern lava field, evidence of pyroclastic origin is rarely discernable. However, the content of broken crystals varies widely from ,*ῌ to 2*ῌ in volume. Most lava flows, which were erupted in Stage , associated with frequent ash-emitting eruptions, contain broken crystals more or less than /*ῌ. This fact indicates that magma in the conduit experienced repetitive fragmentation and coalescence due to intermittent explosions prior to outflow. Lava flows of Stage contain much smaller amounts of broken crystals indicating gentle outflow of coherent lava. Relatively large-scale lava deltas developed toward the sea in the eastern lava field. Eyewitness account at that time reports that ocean entry of lava from several points started several months after the beginning of Stage -. Although small-scale breakouts formed at the flow fronts of some lava on both sides, a large volume of the deltas can not be accounted for by secondary breakouts of ponded lava within the precedent flow lobes. It is considered that lava tube system fed lava to form the lava deltas. Key words : Sakurajima Volcano, Taisho eruption, eruptive style, clastogenic lava +ῌ ῐ ῎ ῑ ῏. UVW-XYZ< [$\4 \4 8]9:X. !"#$ %" +3+.&+3+/ '()*#+$. !8^_!àbCANc;=` %"de 2 fgh. ,-."/0123 +./ km- $#456768%9:. A M 1.+ $ij8kl:;=` mno%"hApq!. ; (Fig. +)< =-(>' ,* ?@ABC;%"$D'(. r$DstuDvAwx8BC;=`Ny8z2-XY. EFG$%"HI'JK LMN.OPQRS8T. Z< E{|A()*$#+'FGN}~%"8. +/0῍2//* )? -῍,/῍.* >ti Department of Geosystem Sciences, College of Humanities and Sciences, Nihon University, -῍,/῍.* Sakurajosui, Setagaya-ku, Tokyo +/0῍2//*, Japan. 23+῍+.+3 pq!pq! !# "# ¡. Sakurajima Volcano Research Center, Disaster Prevention Research Institute, Kyoto University, SakurajimaYokoyama, Kagoshima-shi, Kagoshima 23+῍+.+3, Japan. Corresponding author : Maya Yasui e-mail : [email protected].

(4) 162. "·^¸ ¹ _º`»¼. Fig. +. Index map of Sakurajima Volcano (a) and distribution of the +3+.ῌ+3+/ eruptive products (b). Area of submerged lava flow on the eastern flank is after Ishihara et al. (+32+). Isopachs of the +3+. pyroclastic fall deposit by Kobayashi (+320) are slightly modified. Thickness in cm. The squares on the map show the areas of Figs. ,, -a, 2 and 3a..

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(58) Table +. Summary of ash-emitting eruptions and period of eyewitness of incandescent lava during the +3+.ῌ+3+/ eruption of Sakurajima Volcano. Data were based on Kagoshima pref. (+3,1), Omori (+3+0b, +3,*a) and Yamaguchi (+3,1, +302). One month is divided into three in the table : early represents from + to +*, middle from ++ to ,*, and late after ,+. Phenomena including rumblings, air disturbances, detonations and eruption clouds were observed at the north of Kagoshima city and were recorded in detail in the journal of Kagoshima Meteorological Observatory (Kagoshima pref., +3,1). Based on the descriptions of the journal (Kagoshima pref. +3,1), types of ash-emitting eruption are defined as S for eruption with shock and detonation, R for eruption with rumbling and A for eruption without shock and rumbling. Number of days of individual type of eruptions were distinguished by, for more than five days, for three to four days, and for one to two days. Asterisks show the period of tromometer observation at Furusato (Omori, +3,*a). According to Omori (+3,*a), tremor and air disturbances were observed throughout the period of the observation and sometimes detonations were heard. indicate witnessed incandescent lava..

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(113) cS:d62: 2:efA ghij. 167. Fig. -. (a) Distribution of individual lava flow units, pyroclastic cone and craters C+-C0 on the western flank. W + and W- : the remnants of pyroclastic cones. Broken thick curves show restored outlines of collapsed cones W+ and W-, W, : pre-existing domal edifice “Hikinohira” which is thickly covered by the +3+. pyroclastic fall deposits, W/ and W0 : lavas on the pre-existing slope of Yunohira and Atagoyama, respectively, W., W1 - W +. and W+0 : lava flows, W+/ and W+1 : pyroclastic cones around the explosion craters. (b) Three sections (X-Xῌ, Y-Yῌ and Z-Zῌ) through the +3+. eruptive products on the western flank. Vertical exaggeration is two times. Numbers on the sections denote unit numbers in Fig. -a. Gray area shows the +3+. eruptive product. S+ : shoreline before the eruption, S, : present shoreline..

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(177) . 169. Fig. /. Photographs of the +3+. eruptive products on the western flank. (a) Pyroclastic cone seen from Yunohira. C+ : C+ crater, C- : C- craters, C : flat-topped surface of the pyroclastic cone around the C+ crater, F : fractures develop on the cone, H : Hikinohira, M : Minamidake and K : Kitadake. (b) Coarse pyroclast contained in the +3+. pumice fall deposit. It locates +.3km NW from C+ crater. Locality B in Fig. ,. Scale : -- cm. (c) Surface block of W+*. The degree of welding changes from weak to dense downward within the block. It locates +./km WSW from C+ crater. Scale : -- cm. (d) Moderately welded part of W+* near C- craters. It locates *.3km WNW from C+ crater. Note that many flattened pyroclasts are contained. Scale : -- cm. (e) Densely welded part of W+* near C- craters. It locates *.3 km WNW from C+ crater..

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(196) '¨R&£¤/. .$M- E/- E+2 GHI E+3 ]V ^. ^§

(197) '

(198) C4©+- 1* m A]. - _`M

(199) Y2! E,* & E,+ abc. Y2&¢:+2 D=ª« Fig. 3b Y .J!. ZC$defg2! E2- E+-- E+.- GH I E+1 h/ijkMY2! + lm=i9no02M-. pq =. Omori (+3+0b) - >6?¬@M. Y2®¯A $ DFig. 3a cJ- =/ &:ª! Fig. 3a d GHI e <¥9(B. ! E3 E0 rst u!"#g2$vC$. =&02! °9'?±C.

(200) Y2!

(201) GHI.

(202) YZ- B'[4²³´M

(203) '<DRµ

(204) E¶. w%&3456xyz{| (Fig.. +&:ª2!

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(206) C(/.$- w%M0=3456. 3b X .J!.

(207) 172.

(208) . Fig. 3. (a) Distribution of lava flow units, pyroclastic cone and craters C+-C2 on the eastern flank. Units with simple numbers are T+ lavas, while those with white numbers on a black background belong to T, and T,῍ lavas. Areas S+, S, and S- are submarine lavas of which thickness estimated by Ishihara et al. (+32+). Broken thick curve shows an assumed area of pyroclastic cone E+. Arrows show assumed direction of lava flows. a : Locality of “Akashi-gongen” at the time of the eruption, b : flat-topped depression which is considered to be buried by post-eruptive reworked sediments. c, d and e : slope covered by the +3+. pyroclastic fall deposits, f : area covered by the +3.0 lava. Seto, Waki and Arimura are villages buried by the +3+. lava. T : Tatsuzaki, S : Shiwofuki-zaki. (b) Three sections through the +3+.ῌ+3+/ eruptive products on the eastern flank. Vertical exaggeration is two times. The +3+.ῌ+3+/ eruptive products are shown in gray, which is limited to subaerial part for Z-Z῍ section along a pre-eruption o#shoreline. Broken lines in the sections X-X῍ and Y-Y῍ are estimated sea floor based on the pre-eruption topographic map. S+ : shoreline before eruption, S, : present shoreline, N : Nabeyama, G : Gongenyama, M : Minamidake.

(209)

(210) . 173. Fig. +*. Photographs of the +3+.ῌ+3+/ eruptive products on the eastern flank. (a) Panoramic view of the eastern flank from the top of Sakkabira on October +3+0. N : Nabeyama, A : Akashi-gongen. (b) Photo of the area shown by square in (a). It was taken on ,, April +3+/. Black, blocky lava (L) can be seen in the foreground and T+ lava and E+ pyroclastic cone in the background. Photos (a) and (b) were taken by the Imperial earthquake investigation committee at that time. (c) Occurrence of the surface blocks of E2. A field note in the center is +/ cm long. (d) A block in E2 showing variable degrees of welding. Non-welded part can be seen around the hammer with .. cm long. (e) Blocky surface of E,*. A hammer in the upper center is .. cm long..

(211) 174. ´µz¶f·L¸¶=¹oº¶{»2¼ Cab=%D'an)op= 3 5qrDsE F-t +322 G ,-9 ' BG( E/ E0 = _

(212) uv()

(213) *H (+3+.) 9=-%D ()3uv3' Koto (+3+0) + 6 ,1%D= ()3uv3 w=9= Ix? yJ' ()

(214) ' <z%D () Fig. + K#?BG(9=(F=2 L+{+,MN-#?' , m W*OP@) +5>>f|+,-MN=Q9=}

(215) E/ E0 ? %D'9= 33 Koto (+3+0) '~.3RS'_

(216) T=. Fig. ++. Diagram showing stratigraphic relationships between units of the +3+.ῌ+3+/ eruptive products on the eastern flank. Black tie lines between blocks are stratigraphic relations based on the aerial photos. Approximate month is shown on the right. See subsection -ῌ- for the periods of generation of individual lava.. 9=? T+ . T, %D@) }3 ' 9=%D!X) RS'f 2UD= ( Va%D= () +3+. + 6WD'2UDX} 3

(217) Y'Z %D[YZ\# 0'

(218) Jaggar (+3,.) + 6 -* 1>] ^.3a,d'g3' , 6]?4'_.3 `.3 Koto (+3+0) , 6 + 1 ; (+31/) ,. E ,

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(220)

(221) . #A=_

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(229) (Fig. 3a) g3 E0. . +3+0b Fig. 2. +3+. . 6789 . e

(230) +3+. . 6( 1 6%DD. ῌ

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(235). (Figs. 2, 3a) E. C/ +;(F(+;). (Omori, +3+0b) U)(67.3%D)fì. . +;)?@* +* m =

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(251) (Figs. +*c, +*d) w=. ?@

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(258) XYSt@T. E+* E1 E++ %. E++ & '. (%

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(272) N. HI, J, E+* 8 -!".K. U Fig. 3b Z ^ E2 $ E+1 m !L.

(273) L

(274) M E+* , N .. ]_

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(281)

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(284)

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(300) ?PMg$" 3jp& ¦§ E,* E,+ +** m. g$_B. !: , + km !: L +, 0* m !: Yq-. 9 h

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(303) r{ stuv- ¦§). +- $, E+.

(304) E+- E+.. )w3 E,* E,+ #-xy't. .

(305) R B . :;P":

(306) o¤ D E+2 ¥g\ E+3 . :&jEk'F- G)

(307) _ .

(308) z8¨' (Fig. +*e) ©p {ªA. E+/ C2 01 /** m lmHI3./'. «V" 7| g-!¬'U _

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(310) _. ' E,* L T B E,+ U B . (,**-). E+- E+. JK3-! (n)

(311) +3+. 8 / ,/. 1- )

(312) 8 (Fig. 3a) ¦§ )wa. HI J,'

(313) 3 J,

(314) 9. b® 0ῌ- }"tu3. n -!9 bD:AB 3 . !L"¯~ab °g] M ±². ,0 L6 M Nn , on 01"apO7

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(317) rQs

(318)

(319) / . @ , L;

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(321) M" 0. : E+0 tu % E++ abAv'. 1

(322) ¡ X , b T+ ¶'·. wM 3 :; C2 01 E+/. ¸ , N¹

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(324) ´µ¢P¶· ¸.¹QºR»¼. 176.

(325) .

(326) . (+3,1) (+320) (,**+). !. "

(327) (+320) # +* $ SiO, %

(328) &' ῌ( )*+,-. 0,ῌ / 0 12 /2.130+.2ῌ

(329) (+31/) 24 , * + *5 66 SiO, 0

(330) , *789:; < =>

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(332) CC D EFGH0IJ 13 KL M:N

(333) SiO, %

(334) /2.-30-ῌ . 7 ..1ῌ . :O; (Fig. +,)

(335) !$0. SiO,-MgO #: Fig. +- O; SiO, $PQ". #R STUVW:X;

(336) Y,. Fig. +,. Frequency diagram showing distributions of SiO, content of the +3+.῍+3+/ lava. For definitions of T+, T, and T,῎, see text in Chapter ,. An arrow shows the range of SiO, content of the +3+. pumice fall deposit.. D T+ T, ?@ T,῎ Z5

(337) T+ $ T, :[; $\# 0+./ῌ YR$ SiO, $]^_

(338) T+ D%&`. 0+.330-ῌ $ a0 %12 0*.03 0,.1ῌ $bcd (Fig. +,)

(339) D% SiO, %.

(340) e)*+,-.12$fg'(

(341) % T, &` /3..30,..ῌ T,῎ 12 /2.-30*.2ῌ

(342) T, $ T,῎&`fg'(. T,῎)hiE SiO, %

(343) 0

(344) % T+ $5 $ 0*.030,./ῌ j &`'* ; (Fig. +,)

(345) SiO, %

(346) +k T, &`$'* ; T+ lhiE,m;

(347). Fig. +-.. SiO, vs MgO diagram of the +3+.῍+3+/ lava.. D% (T+) SiO, %

(348) nopT qrF2

(349) W3 stuVvwxL? l y- ". (Figs. 1e, 1f)

(350) %. ?<:.65%] (Figs. +/a, +/. E0 E1 E++ E+, E+/3+1 0+..ῌ /0. b)

(351) CC ?B-{hFi 0 l?C. (Fig. +.)

(352) E+* $ E+. 1z{|EFr $ T,. 2<F2 I ?<$;

(353) De. $}~F2 /L:GH0:2. l EF. ?<F.D%

(354). ; 34

(355). &Y, BPL $( :)G HI0

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(358) . 8t9$IJ 31 : ;<:N

(359) =.~ .> 6?<$%

(360) @A0 :Y,Z5

(361). *./ mm YR?<F.D:20 ¡¢§:. ¨ -) ©ªVT«¬VTG ?<F.$?<. . F.:HI; .) ?<F.D %

(362) &NOῌ( :®<

(363) BPL¯+**°&BPL*±&BPL*²NPL((. CC BPL* ?<F.«¬VT³ NPL ?< F.«¬VT³

(364).

(365) ºW~ ]~]~¦8»¼T. 177. `yG o8_& (Fig. +/d)

(366) BPL H ++2.ῌ $ (Fig. +1)

(367) 0*ῌ 23 BPL ' !. =>?@ABCDE&F s +6'`, &

(368) .*0*ῌ I!=>?@ABCDE&F. (Fig. +1)

(369) W3 d>eSfghi71j. k&l 0*ῌ J:& (Fig. 1f)

(370) K!= D' BPL H$bc$ (Fig. +0 a)

(371) sXs W. W3 8 W+* LM^ W+, LM. N^ BPL

(372) W+0 _ BPL N&* +./0 &bc$

(373) I Fig. +0a Q Os PsXs i7 $ - 0῍+ F)

(374) Fig. +.. Map showing spatial distribution of SiO, content of the +3+.῍+3+/ lava on the eastern flank. Units with simple numbers are T+ lavas, while those with white numbers on a black background belong to T, and T,῎ lavas.. /ῌ, . LM+6 ! ". , mm, 1 /./ mm ./0*+,.

(375) j+67$,% =>?@A BCDEyGu

(376) ,G'()H+ **H + RSTS+ *+IJK+,G'$

(377) RS. BPL Fig. +0 Fig. +1

(378). TS+./0 *., mm J: ![P &Q "#&

(379) RSTS+2 + -. /ῌ+ . .()"# >p + 8 + -..

(380) . 2jsX3^&"# >p , $. !.

(381) T+ >p , & T, >p + 8 , . "#$

(382) % "#&. !9 T,῎>p + u$

(383) T, 8 T,῎R. '!($

(384) )*+. RSTS+Xz\,'ss3^

(385). ,!- !*+./0" +.1 mm, 1 - mm $ *+./0" , mm 231 0 mm #. . 4a,G'&i7+6'`, &

(386) BPL H +- 2+ῌ $ . *+45. (Fig. +1)

(387) +*-/ῌ 51' (& .*0*ῌ . %"#8 %. &

(388) ./ῌ 23i7=>?@ABCDE&F. "#!9 :;<%=>?@ABCDE&F. "#S$

(389) T+ BPL TH /*ῌ J. (Fig. +/a)

(390) ,G'()H+ **H+ *+. :ww&

(391) T, 8 T,῎ 1 Y23 +*-/ῌ 8N&. IJK+,G'$

(392) LMNO /, -.. BPL (Fig.+1)

(393).

(394) +67$,%$. PQ /0RSTS+4U'VWX + -$O , Y.1Z[RSTS+4U*+8. 0

(395) . H+\,]23^

(396) _.'456. 0ῌ+ !"# . `,45 4a,G'&.. U V W XYW Z_ ~. +6'`,4&bc$

(397) W3 d>eS. I&l~¡z ¢S[£¤ ~¥\~¡'. fghi7 1j k&l<%=>?@A. }j ]~¦(&l§^¤l& S. BCDE&F

(398) W+* G, 89 (Fig. ,) . ¨ Sumner, +332 ; _ ` © ª « ¥ ,**+ ; Yasui and. mi7n +, mm . Koyaguchi, ,**.

(399) =>?@ABCDE&Fab¤. o. :;. pgeh o< =qars. `¬<%"#k8 !~¡z . >tTp'u (Fig. +/c)

(400) =>?@ABCD. 8~¥X®csdecM 2j )¯ 8°. E&F v?O ow456@x!yz. ± ²fg³&

(401) }j{+h´'4a. AB`,'3^

(402) !* Fig. , C 89 . AB`,45^ µe >¦]~JP. {+C|DP}j~E 0῍. F: <%. ~¡]~`,'¶·¤¸8¹i¤.

(403) 178. µ [¶·N¸¹º»¼. Fig. +/. Photomicrographs of the +3+. eruptive products on the western flank. (a) Eutaxitic texture in the surface lava block of W+*. Lines denote broken surfaces of crystals. Many broken phenocrysts and crystal debris are observed. Open nicols. (b) Broken plagioclase contained in the bore hole core sample of W3 (,+ meter in depth). Inner zonal structure is clearly cut o#. Crossed nicols. (c) Vesicular, pyroclastic grains from non-welded part of W+*. Sample was taken at G, (Fig. ,). Grain-size of particles is + ῍ , mm in diameter. Note that some glass shards are remarkably elongated. Open nicols. (d) Grains from an ash fall deposit which overlies the +3+. pumice fall deposit. Subangular, massive, lava fragments are dominant. Sample was taken at the locality of C in Fig. ,. Grain-size of particles is +῍, mm in diameter. Open nicols.. ,**-

(404) . ,**0

(405) yz{ |./0&.

(406). }N~lmnopqrstuv *+. !"#$%&'() *+. ! EK

(407) E 0}./. !,-./0&1(23

(408) 4. 0&!~lsG'L=L. 5 6 !"#$%./0&*+. G

(409). 7389:;<'=

(410) > ?4. f%!kst. @& ABA.CDE.FG. 0:<y!3

(411) n + (gE. HIJ1KLMEK

(412) NO/G. =L G #stEK{ ?4. ./0&PQGRST O/U1V%!K. st@E¡¢G^_£1(

(413) ¤E.. W *+!,-XYZ!./0. /0&!"k (BPL : 2*ῌ ¥ ) N~1lmnop. &1[\]G^_àS

(414) bT!cde f. qrstuvG¦_£1(

(415) n , §E(. fghijE ./0&!"klmno.

(416) ¨0stE ©ªZ«¬®¯Z°±. pqrstuvG^_1w<xK>1^3. 8²9³M

(417) ./0&1´'<|.

(418)

(419) . 179. Fig. +0. Broken plagioclase content of the +3+.ῌ+3+/ eruptive products of Sakurajima Volcano. (a) and (b) show spatial distributions of BPL content of lavas on the western and eastern flanks. Asterisks are samples with well developed eutaxitic texture. Numbers with ‘Q’ are samples taken from squeezed out lava. Open square in (a) shows the locality of bore hole..

(420) ³´µi¶x·N¸¶¹º¶j»&¼. 180. &H'(12 +3+. ) - c ,, * +, C0 ; \-L4d.W8DA+ #/ +* m e0 2123fbgAF Nh\ +31/P i j4 W++ W+, W+0 E++ E+0 8W 56>kH W+, ! DlDlm m nopq 7r[D 89$W342 W:; HG< =>s ?@A*Bt2F TU42 W+, 7r[DW BPL /*ῌ CK (Fig. +0a) ugA W+, !vwH BPL x. + ;\].yz. 2FBCQR i2 W+, {| C0 ;\!] W- ;<=?B5iD. W+, }~)AKEF G>HH W3 p "%;<W. >)F W3 ;<6WTU42 W3 }~ GHIJ42$ W . W+* . + iL4 G. HIA;<6QRx i24 Fig. +1. Frequency of BPL contents in the lavas from the western and eastern flanks. Open circles : samples with a distinct eutaxitic texture, T+ : lava flows generated mostly in January +3+. on the western and eastern flanks, T, : lava flows generated after February +3+. on the eastern flank, T,῍ : lava flows, which form lava deltas near Arimura coast, probably generated after the summer of +3+... [7)A KD.LH M,&N ; ["! NW+* ! OPP QA J"W!DF; <Z3 NO +320P RS TD JLgAaH W+* B5 U %DF;<JWV >@FFFZTUW>r DL D KLH,Z W+* ! W+ ;<= "&X$$5B5*YHi W+* ; <=:;;<6Wi>.kH ;<. (BPL : +*0*ῌ)

(421) . )A + c +/ *KD @ Z[. . >7DFZ ¡\ Nh\ +301P Jaggar. W. W+* . (+3+.) , c"¢

(422) £[¤12F¥>j¦D §. + W+* ! "#$. ] ¨©VH,TUF i24;<. % &' (Figs. /c, /d, /e) W3 ( E1 E2 . {| ^[ L4 C, ( C. ;\!]. +

(423) ) * W++ W+, W+0. TU42A (Omori, +3+0b) ;< _mªD. . E/ E0 E+* E+- E+/ E+3 E,* +,- E,+ . . . , . E+3 E,* E,+ ! . + /$. + 012$. + 34256. 7 +) 89:;<=>*?1@AB CDAEDF ,) GHIA;<6 -) J!KL4DF;<>M@A. EDF NO +320P - )QR. F B `DA>¤HX $LgF TU42 W(R/a >¤DF;<$ U$ M,hb! ">«.cZX;< wD$T U42 0ῌ,

(424) Head and Wilson (+323) ( Sumner (+332) W d. ,;\]e¬FR>kD. d®. SBCQR)ATU VW8. f( ;¯©g DFL>°gF ii ±M. XYW,Z [\!]L4". ,hb W. W+* ¬(B5U²h. W#^. _`$a%Jb. DA;<6W[7>TU.

(425) »L ,_3¼ R:gq. 181. -ῌ+ C-

(426) . u1 g13i. (Fig. -a)

(427) . 6 %E (Later collapse generated lobe) 2*. ,* +,+/* m . 345 W+* W. +`"83( |. !" #$%&'. KL jY3c4b'T )2"& W+* . (Omori, +3+0b) ( C+ )* C- +,-. W#( C- +%8W#k8. ./0 #12 345*. `4wxyzlg J+j)TKl)q6 (Fig. ,). . W. ( W+ 676. C- + %(0 ,)T. 83)* W+ 6345*. <% e# -."345. 39. * ; % <" g13i%. :( W. ( + km ;. !. < =Fig. -b Y "#> ?@ABC Pu’u ‘O’o. W+* %E+J"34583V. +32-D20 $ %E & ,' F(( GH. W+* (m %XEn""- 8. )I #$J"KLM %ENOP

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