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The ,**. Eruption of Asama Volcano, Central Japan
Mitsuhiro YOSHIMOTO , Etsuro KOYAMA , Jun’ichi HIRABAYASHIYC >kl+ ,**.aB (Fig. +)7 ] +3+,**.

and Setsuya NAKADA

(Fig. +)  ,**.

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Volcanic Fluid Research Center, Tokyo Institute ofTechnology, Kusatsu 0.+῍-0, Agatsuma, Gunma -1+
῍+1++, Japan.
Corresponding author : Mitsuhiro Yoshimotoe-mail : myoshi@eri.u-tokyo.ac.jp¸d¹ºmO »emfg¼m:hi418

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Fig. +.

Locality map of Asama volcano.

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Table +.

419

Chronology of major episodes in the ,**. eruption at Asama Volcano.

Fig. ,. Schematic illustration of the summit crater of
Asama Volcano before and after the ,**. eruption. The two ﬁgures are same as photos Nos. 1and 2, respectively. Accumulation of lava andpyroclasatic materials shallowed the crater bottom.
Solid and open stars mark the identical points,respectively, between the two ﬁgures.

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420! #}/ῌ ῕ ΐ ῎Kazahaya, K., Shinohara, H., Uto, K., Nakahori, Y., Mori,H., Iino, H., Miyashita, M. and Hirabayashi, J. (,**.)
Gigantic SO, emission from Miyakejima volcano, Japan,caused by caldera collapse. Geology, -,, .,/ῌ.,2.
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Photo +. Eruption cloud of continuous strombolian explosions at Asama Volcano on +0 Sept. ,**., from above
Kusatsu-Shirane volcano, about ,/ km NNE of Asama, taken by J. Hirabayashi.
ῐῑ ,. 27{|t<  = ,**.  ++  ,. m {| ~Photo ,. Easterly view of the summit crater on ,. Nov. ,**., taken from helicopter of Nagano prefecture. Taken by M.
Yoshimoto.
ῐῑ -. 3  +*  ,* )< =$ . km  9! ~
Photo -. Glowing of the summit crater, seen from Asama Volcano Observatory, about . km E of the summit, taken in the+* Sept. night by E. Koyama.
ῐῑ ..
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Photo .. Strombolian explosion at Asama Volcano, on +0 Sept., about . km NE of the crater by J. Hirabayashi.
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Photo /. Aerial southeasterly views of the summit crater of Asama Volcano on + Oct. ,**.. (a) Vent of the ,- and ,3Sept. vulcanian explosions was observed in the center of the ,**. lava. (b) Close-up view of the photo / (a).
Ballistic megablocks of the ,- and ,3 Sep. explosions were scattered around the vent. Taken from helicopter ofNagano prefecture by M. Yoshimoto.
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Photo 0. Aerial southerly view of the summit crater of Asama Volcano on ,0 April ,**/. (a) The vent was enlarged bythe +. Nov. eruption. (b) Close-up view of the photo 0 (a). Lava wrinkle was observed NW margin of thelava. Taken from helicopter of Nagano prefecture by M. Yoshimoto.
ῐῑ 1.  »
 = +333  .  -*  =¹¼{|! ~
Photo 1. Summit crater of Asama Volcano before the ,**. eruption, taken from the W rim of crater on -* April +333 by
E. Koyama.
ῐῑ 2.  ,**/  1  ,2  =¹¼{|! ~Photo 2. Summit crater of Asama Volcano after the ,**. eruption, taken from the W rim of crater (same point as in Photo1) on ,2 July ,**/ by E. Koyama.