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Announcement of Volcanic Activity Level by Japan Meteorological Agency
Hitoshi YAMASATO, Shoichi OGA, Yutaka DAIKU, Jun FUNASAKI,Masaya MATSUSHIMA, Hirohito NAITO and Tomoyuki KANNO+ABCDEpUVk\ / $= ,**-  ++  .   ()*+W-Xa'o12 7Y   /  !/ "# $%&  (,**- b) $maM'&=2  ' ()*+,-./012 34 ABCDEpT-m$0k\ $HI?Z

()*+ 56789$%&':;<=28[0 G$ (- *  / 40S,$\=m$0 / ()*+

]-Xa12 7\Gk]K- Table + >($?0'@-A& $<2  ()*+-^$HI?Z

(B$CD' ! EF ! "G\_`Z$H*C-m=a4bc%mk= ! @ !# -#0'&=2  !

m-de$]12 71a$HI?J!%I?-&D'K'$()LM $H*N

pG6£g¤$¥¦' hD()*+4#$(+LM'&=2 ,**,  O, - .P

i<=AjZk$§k=Il$¨©=-V/QRS !TUVW$@XWV-Y0kgk¦12 70' ()*+ª<=¥«0'

!-#1<=Z2[\3]M1 (f¡J¢$ kl9\56mkw ¬­G$k$mn
`=mk¦'&=2 ®¦' QGk\,**- a#2

 !$%&' 4^_4`=1abcJd

Table + $<¥«$ WGk_JA!;hij\kjf¡m&«¥w k((#LJ

e567\89$:f0$g&&4(< =>\l?mn@LM'o12`Z$H*C567¯&40'`=2ABCDEp +33/  !AFiG)*+ * : A(J7^oZ°aFikB$?<=qWrUss+Wt" H$ ! !

(p±\k&q2uvs+Wt" -IJ0'  !`wK$%&')*+ + : A(J7^oZ`=\ r²kxL-yz {|4A}M'&=()*+ ~(4 Ap±\Mk&q2

WW# M] QN +33-# -OP<om0'

)*+ , : 7^os#Z7§t\M +333  ,  !()*+QGnR AS

(q-³¦'&g56\`=JJ(#k#" -$T012 7   ´+**ῌ2+,, .PuvwNµx +ῌ-ῌ.
^oy¶
Volcanological Division, Seismology and Volcanology Department, Japan Meteorological Agency,+ῌ-ῌ. Otemachi, Chiyoda, Tokyo +**ῌ2+,,, Japan.
 ´2+*ῌ**/, /Q·H¸¹ +ῌ,ῌ-0/Qº-»¼y^o¶(q2Seismology and Volcanology Division, TechnicalDepartment, Fukuoka District Meteorological Observatory, +ῌ,ῌ-0 Ohori, Chuo, Fukuoka 2+*ῌ**/,,Japan.
Corresponding author : Hitoshi Yamasato
e-mail : hyamasat@mb.infoweb.ne.jp

\ ]± ²³G± ´ ^±µ ¶±·H¸¹±P_º»±¼`ab218
Table +.

General deﬁnition of the volcanic activity level.

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

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,3  B",**- M ,.  ^";<*eW¢M£X ;<*X , 6' *1W"YZ I[\ ]B^

,"D$_.6,GHE!J"D

6*^,3 

 /!=6tu¤¥"$

XW /6,3  /!B.$`\/ 0CFE7¦§ ¨©ª X «Y

a123"D G4 ]B B.E

V5 ¬ ­kj$6®Z" GC6, FV5a1b6"23 F"6789!"CE. .V5a1239cd 63<:;.F!,' (Minakami, +31.) /! ­kj$6e(,f"*;^, !

B ¯ª°[q C ( 2  - 6789! ;< 
Table ,.

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Volcanic activity level for Asama volcano deﬁned by Japan Meteorological Agency.

  3De 3Dvd#     ! "7 3U$4i7+ 384 ,  + -#$%&'( )*+ ,-3456789 :;./012 -+ <= , >?@$012 , AB 6 6 U$4_

312 . B6i7+^ 7N( 312 / B6C3DE12F9GH IJK)LMNO?D3D PQR ,**.  - S 3DEDDd)3B7+ ~&#%&'4(12T6DUV' W 12 + )3X  /** m 12 , )3X
 , km Y 12 - )3X. km Z[\]^]

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  3D 456i+)12 ,+3DE 4E6,- 5a4`8912 -`3512 .

hijkl1'jmnNB Ao? fg_`

-ῌ- q-^rs 12 - d

63D 456 )* +321 AB

ab ! c +30. defg&'(3^12 , d )56*+ 3p! +30. defg

AB¡6¢.N

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HAB 6 6UV8,}73

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5²6"989 12 . BNAB& D)`3456# 6 Table .

  +33+ t) DD3X 312; ! 3D ³ 5´µ

:N

! 4  C0E # D3X 3Eafg¶· <¸5´µ*¹$%04B7"4  A) Table -¦´µ @º #B 6  DD)3E6}vwxnyz{3 

12 - B6 A123) ~&6   ! $%&'(<¸=¼N}7Ehi 3X»*
"+12 - ¢6j kl;mnol;p qlrs tluvwxlYyz{l|}~

220 

 !"#$ %&'() + *+ ,-./012-3456!'$ ,**. 7 + + +. 8$ 9:;<=>?
Table -.

$ @AB'CD6E
G - HWDNFG + km XYRSTUZ[\ 3 C]^_U`abcde=>?fghRi Volcanic activity level for Izu-Oshima volcano deﬁned by Japan Meteorological Agency.

Table ..

,F

3 IJKLM'DNOPQRSTU9V

Volcanic activity level for Aso volcano deﬁned by Japan Meteorological Agency.

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 +,+-   ,   
!"#$ " %#&

'()*+ ,- !"./
0+

1

0234567#890:;14,+

P-8* 0 .

%@

1  8*e - Q   ./00 /1-ῌ/1]^# +3// >2314,+4\!5"0i<= +311 >? ,**.  .

221

061 p3,4,+" /* Y , km >#w7<8# ABCD%EFGHEIJ*+ ,-90:14   Q14,    + # -0++  K-0ῌL    , # -0+1 4i; W ,st "0

K-0ῌL  - # ,03,  K,1ῌL  . # 0, +, 4#f4 Table 0 +P- < !

M N0O*+P- ;S+ v6 4,+ T14!5

Q1#RS ,0* &+ T K32ῌ * " 1]^ - N!=>*K+ῌL+ ,/0 L #T% - >U+ 11 Q% ,+  . WX3& T-< +VV4,K+33,  32 L# YZ%N0O14,+

14,+  ?U8* *+ # /+ 1,4 #st "0 +*+%@#0_1 K-ῌ.  !A (,**- a)%g1EFGHEIJ¡¢#T-%&+L  - B[!\]^# +33* _ " KOhta
et al., +33,+P-"0 .

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1 st3%p B ¯° k Q K± +32.L ²G³´

&q, 'V+r(0 * !"# +  u,%i !"
+ T14 xy)8* -*+

Kz{l+ 0j|L 0,+

1 ,}~H,}-OA14*+Table /.

H KµI¶N· +320L

14,vw Q1 'V+]^0 ,  "" J¸

K4,+A¹iCDµ 4º»bHc0i EFGHEIJ*+  4\%

Volcanic activity level for Unzen volcano deﬁned by Japan Meteorological Agency.

r hkV·{kV¸ |k¹ ºk}q~»k ¼k222
Table 0.

Volcanic activity level for Sakurajima volcano deﬁned by Japan Meteorological Agency.

 +32*+323 
 ,



1+3  ,*ῌ    -,0+3  1,ῌ  .

 -+/  2ῌ ,**+  1   ,!
-,  -ῌ-?@ #EABi!+ ! 6%! #jC

#EABi!+ /## a: p,**.  . 

+**-  31ῌ "  . # $%& dI$%D% XI$Ek6lm =nXoFq

 rGHs tu vIws JK"! 2W# xyzL#M01Xxyk{|}~Ng#)!+.ῌ ῎ ῍ ῏'()*+,#  #-.
'- " '-#/01(23#4,5%67  ,*** 8&91:5;  '<=>?#701
+,@;"#A67 B%#/01 '-75%;0" C5#

DEFG7";H B ,  !" # #=1 I$%7'<= &<=>?J'(KLM, J'

N: $O 7/P # Q)  *R'<=#701 +S+71TU#,MM VW  X # /". YZ /# / [ \ 01, I$%  VW / 2#34#5]^678#_`# Q)+9 ΐ

ῒ

#a:+#" ;Ubcd9<=>e fg .,7+hῐ ῕ ῔ ῑOkPQ (+320) *RS=^6 TU$% ?$ V' ,3B-+ +῍+,.
I$% (+33+) DWX Y , Z /** p.
u[\ (+31-)   NHK  ,-* p.
Minakami, T. (+31.) Seismology and volcanoes in Japan.
In Physical Volcanology, +῍,1, Elsevier.
 L (,**-) ] ^ _ `a
12 ,2-῍.0-.
b (+32.) c#?+d B *`  V' ,1B-+ ,3῍-..
Ohta, K., Matsuo, N., and Yanagi, T. (+33,) The +33*῍+33, eruption of Unzen volcano, In Unzen Volcano the+33*῍+33, Eruption. The Nishinippon & Kyushu University Press, Fukuoka, pp. -.῍-1.
(+33-) <#E^67fgk9e#=+¡ hi -k. #jkl¢£ 3,῍+-,.
mn¤j (+321) : do;5¥¦pVq<§ ¨*© 32 .1/῍.2*.
r h (,**- a)  xy7ªe\ st .2 ++/῍++3.
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