㧠㧙㧝 㑐᧲࡮ਛㇱ࿾ᣇߣߘߩ๟ㄝߩ࿾㔡ᵴേ㧔ᐕ᦬㨪ᐕ᦬㧕
Seismic Activity in and around the Kanto and Chubu Districts (November 2008 –April 2009)᳇⽎ᐡ ࿾㔡੍⍮ᖱႎ⺖
Earthquake Prediction Information Division, JMA੹ᦼ㑆㧘㑐᧲࡮ਛㇱ࿾ᣇߣߘߩ๟ㄝߢM4.0એ਄ߩ࿾㔡ߪ108࿁㧘M5.0એ਄ߪ19࿁㧘M6.0એ਄ߪ3࿁ߢ޽ߞߚ㧚ߎߩ߁ߜᦨᄢߪ㧘2008ᐕ12᦬20ᣣߦ㑐᧲᧲ᣇᴒߢ⊒↢ߒߚM6.6ߩ࿾㔡ߢ޽ߞߚ㧚2008ᐕ11᦬㨪2009ᐕ4᦬ߩM4.0એ਄ߩ࿾㔡ߩ㔡ᄩಽᏓࠍ╙1࿑(a)෸߮(b)ߦ␜ߔ㧚ਥߥ࿾㔡ᵴേߪએਅߩߣ߅ࠅߢ޽ࠆ㧚
㧔1㧕㑐᧲᧲ᣇᴒߩ࿾㔡 㧔M6.6㧘ᦨᄢ㔡ᐲ3㧕㧔ᧄᏎ̪1ෳᾖ㧕
2008ᐕ12᦬20ᣣ19ᤨ29ಽߦ㑐᧲᧲ᣇᴒߢM6.6ߩ࿾㔡㧔ᦨᄢ㔡ᐲ3㧕߇⊒↢ߒߚ㧚ߎߩ࿾㔡ߪᄥᐔᵗࡊ࡟࡯࠻ߣ㒽ߩࡊ࡟࡯࠻ߩႺ⇇ઃㄭߢ⊒↢ߒߚ࿾㔡ߢ޽ࠅ㧘⊒㔡ᯏ᭴㧔CMT⸃㧕ߪ᧲⷏ᣇะߦ࿶ജゲࠍᜬߟㅒᢿጀဳߢ޽ߞߚ㧚ߎߩ࿾㔡ߦ઻޿㧘ጤᚻ⋵ߣችၔ⋵ߩᴪጯߢዊߐߥᵤᵄࠍ᷹ⷰߒߚ㧔᷹ⷰߐࠇߚᦨᄢߩ㜞ߐߪችၔ⋵⍹ᏎᏒ㞜Ꮉߩ15cm㧕㧚߹ߚ㧘૛㔡ᵴേߪ12᦬24ᣣߦM5.5㧘
20ᣣ㧘21ᣣ㧘25ᣣߦM5.4ߩ࿾㔡߇⊒↢ߔࠆߥߤᵴ⊒ߢ޽ߞߚ㧚ߎߩ࿾㔡ߩ1ᣣᓟߦߪM6.6ߩ࿾㔡ߩ㔡Ḯ߆ࠄ⷏ർ⷏ߦ⚂20km㔌ࠇߚ႐ᚲߢM6.2ߩ࿾㔡㧔ᦨᄢ㔡
ᐲ3㧕߇⊒↢ߒߚ㧚ߎߩ࿾㔡ߩ⊒㔡ᯏ᭴ߪ㧔CMT⸃㧕ߪ᧲⷏ᣇะߦᒛജゲࠍᜬߟᱜᢿጀဳߢ޽ߞ
ߚ㧚
㧔2㧕ਃ㊀⋵ਛㇱ㨪દ൓ḧ࡮ᄹ⦟⋵ߩᷓㇱૐ๟ᵄ࿾㔡ᵴേߣߘࠇߦ઻ߞߚ࿾Ზᄌേ㧔╙2࿑㧕  2008ᐕ11᦬10ᣣ㨪18ᣣߦ㧘ਃ㊀⋵ਛㇱ߆ࠄદ൓ḧ߅ࠃ߮ᄹ⦟⋵ߦ߆ߌߡᷓㇱૐ๟ᵄ࿾㔡ᵴേ߇᷹ⷰߐࠇߚ㧚ߎߩ㑆ߩᦨᄢߪ11ᣣߩM1.0ߩ࿾㔡ߢ޽ࠆ㧚߹ߚ㧘ߎߩᵴേߣหᦼߒߡ᧲ᶏ࿾ၞ෸߮
ߘߩ๟ㄝߦዷ㐿ߐࠇߡ޿ࠆᱡ⸘ߢ࿾Ზᄌേ߇᷹ⷰߐࠇߚ㧚ਃ㊀⋵ਛㇱߢᷓㇱૐ๟ᵄ࿾㔡ᵴേ߇᷹ⷰߐࠇߚߩߪ2008ᐕ6᦬એ᧪ߢ޽ࠆ㧚
㧔3㧕ਃ㊀⋵ߩᷓㇱૐ๟ᵄ࿾㔡ᵴേ㧔╙3࿑㧕  2009ᐕ2᦬12ᣣ03ᤨบߦਃ㊀⋵ߢM0.6ࠍᦨᄢߣߔࠆዊⷙᮨߥᷓㇱૐ๟ᵄ࿾㔡ᵴേ߇᷹ⷰߐࠇߚ㧚ߎߩᷓㇱૐ๟ᵄ࿾㔡ᵴേߩ⚂30ಽ೨ߩ02ᤨ34ಽߦߪࠗࡦ࠼ࡀࠪࠕߩ࠲࡜࠙࠼⻉ፉઃㄭߢM7.2ߩ
࿾㔡߇⊒↢ߒߡ߅ࠅ㧘ߘߩ࿾㔡߆ࠄߩਥⷐߥ⴫㕙ᵄ߇೔⌕ߒߚᓟߩ03ᤨ00ಽ㗃߆ࠄ㧘੹࿁ߩᷓㇱૐ๟ᵄ࿾㔡㧔ᓸേ㧕ᵴേ߇⊒↢ߒߚ㧚ᵴേߪߔߋߦ෼߹ߞߡ޿ࠆ㧚ߥ߅㧘ߎߩ㗔ၞߢߪᐕ2㧘3࿁⒟ᐲߩᷓㇱૐ๟ᵄ࿾㔡ᵴേ߇޽ࠆ߇㧘੹࿁ߩᵴേߪᓥ᧪ߩᵴേࠃࠅ߽࿁ᢙ߇ዋߥ޿㧚㧔4㧕ߘߩઁߩਥߥ࿾㔡ᵴേ㧔╙4㨪10࿑㧕⊒↢ᐕ᦬ᣣ   㔡ᄩ࿾ฬ      ⷙᮨ(M)  ᷓߐ(km) ᦨᄢ㔡ᐲ2008ᐕ11᦬24ᣣ  ጘ㒂⋵⟤Ớ᧲ㇱ     3.9     2009ᐕ- 123 -

11      4  㧔╙4࿑㧕

2᦬ 1ᣣ  ⨙ၔ⋵ᴒ        5.8   47      4  㧔╙5࿑㧕

2᦬16ᣣ  ጊ᪸⋵ਛ࡮⷏ㇱ     3.8   20      3  㧔╙6࿑㧕

2᦬17ᣣ  ජ⪲⋵ධㇱ       4.6   

31      4  㧔╙7࿑㧕

2᦬18ᣣ  ጘ㒂⋵⟤Ớਛ⷏ㇱ    5.2   

9      4  㧔╙8࿑㧕

2᦬24ᣣ  ᣂẟ⋵ਛ⿧࿾ᣇ     3.4   

11      4  㧔╙9࿑㧕

4᦬28ᣣ  ⨙ၔ⋵ᴒ        5.0   48      3  㧔╙10࿑㧕̪1㧦‫ޟ‬2008ᐕ12᦬20ᣣ㑐᧲᧲ᣇᴒߩ࿾㔡㧔M6.6㧕ߦߟ޿ߡ‫ޠ‬㧔᳇⽎ᐡ㧕

- 124 -

╙1࿑(a) 㑐᧲࡮ਛㇱ࿾ᣇߣߘߩ๟ㄝߩ࿾㔡ᵴേ㧔2008ᐕ11᦬㨪2009ᐕ1᦬㧘M҈4.0㧘ᷓߐ҇700km㧕
Fig.1(a) Seismic activity in and around the Kanto and Chubu districts (November 2008 – January 2009,M҈, depth҇700 km).

- 125 -

╙1࿑(b) ߟߠ߈㧔2009ᐕ2᦬㨪4᦬㧘M҈4.0㧘ᷓߐ҇700km㧕
Fig.1(b) Continued (February – April 2009, M҈4.0, depth҇700 km).

- 126 -

╙2࿑(a) 2008ᐕ11᦬ߦਃ㊀⋵ߣߘߩ๟ㄝߢ᷹ⷰߐࠇߚᷓㇱૐ๟ᵄ࿾㔡ᵴേ
Fig.2(a) Activity of low-frequency earthquakes in and around Mie Prefecture in November 2008.

- 127 -‫ع‬ٟᱡ᷹ⷰὐ‫ޕ‬╙2࿑(b) ᷓㇱૐ๟ᵄ࿾㔡ᵴേߦ઻ߞߡ᷹ⷰߐࠇߚᱡᄌൻ
Fig.2(b) Strain changes associated with low-frequency earthquakes.

- 128 -

╙3࿑ 2009ᐕ2᦬12ᣣߦਃ㊀⋵ߢ᷹ⷰߐࠇߚᷓㇱૐ๟ᵄ࿾㔡ᵴേ
Fig.3 Activity of low-frequency earthquakes in Mie Prefecture on Feb. 12, 2009.

- 129 - ᦬  ᣣ ጘ㒂⋵⟤Ớ᧲ㇱߩ࿾㔡ᗲ⍮࡮ጘ㒂⋵Ⴚઃㄭ‫ޔ‬࿾Ზౝ‫ޔ‬/ ߩㅒᢿጀ‫ޔ‬๟ㄝߦߪᄙߊߩᵴᢿጀ޽ࠅ㔡ᄩಽᏓ࿑㧔 ᐕ  ᦬એ㒠‫ޔ‬/҈‫ޔ‬ᷓߐ MO એᵻ㧕 ᐕ  ᦬㧝ᣣએ㒠ࠍỚߊ⴫␜ ጘ㒂⋵ṑ⾐⋵㐳㊁⋵ ᐕ  ᦬  ᣣ  ᤨ  ಽߦጘ㒂⋵⟤Ớ᧲ㇱߩᷓߐ MOߢ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧠㧕߇⊒↢ߒߚ‫⊒ޕ‬㔡ᯏ᭴ߪ᧲⷏ᣇะߦ࿶ജゲࠍᜬߟㅒᢿጀဳߢ‫ޔ‬࿾Ზౝߢ⊒↢ߒߚ࿾㔡ߢ޽ࠆ‫ޕ‬ߎߩ࿾㔡ߩ⊒↢ᓟ‫ⷙޔ‬ᮨߩዊߐ޿૛㔡߇⊒↢ߒߚ߇‫ޔ‬ਥߥᵴേߪ㧞ᣣ⒟ᐲߢ෼߹ߞߡ޿ࠆ‫ޕ‬Ꮐਛ࿑ߩ▸࿐ߢߪᢙᄙߊߩᵴᢿጀ߇ሽ࿷ߒߡ޿ࠆ߇‫ޔ‬ᐕ  ᦬એ㒠‫੹ޔ‬࿁ߩ࿾㔡ߩ㔡ᄩ๟ㄝ㧔㗔ၞ㨍㧕ߢߩ㧹㧠ࠢ࡜ࠬߩ࿾㔡ߪ߶ߣࠎߤ⊒↢ߒߡ޿ߥ޿‫ޕ‬㕒ጟ⋵ᗲ⍮⋵㗔ၞ㨍ౝߩ࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑ਃ㊀⋵᜛ᄢ࿑㗔ၞ㨍㧔 ᦬  ᣣએ㒠‫ޔ‬/ ోߡ㧕੹࿁ߩ࿾㔡㧔 ᦬㧝ᣣએ㒠㧕ᄥታ✢࡮ὐ✢ߪ‫ޟ‬ᣂ✬ᣣᧄߩᵴᢿጀ‫ޠ‬㧔ᵴᢿጀ⎇ⓥળ✬㧘㧕ߦࠃࠆᵴᢿጀߩ૏⟎ࠍ␜ߔ㔡ᄩಽᏓ࿑㧔 ᐕ㧤᦬એ㒠‫ޔ‬/҈‫ޔ‬ᷓߐ MO એᵻ㧕㗔ၞ㨎ᤘ๺  ᐕ  ᐕ㐳㊁⋵⷏ㇱ࿾㔡 Ꮐਅ࿑ߩ▸࿐ߢߪ‫ޔ‬ਃᴡ࿾㔡㧔/㧕߿‫ޟ‬ᤘ๺ ᐕ  ᐕ 㐳㊁⋵⷏ㇱ࿾㔡‫ޠ‬㧔/㧕߇⊒↢ߒߡ޿ࠆ߇‫੹ޔ‬࿁ߩ࿾㔡ߩ㔡ᄩઃㄭ㧔㗔ၞ㨎㧕ߢߪ‫ޔ‬ ᐕ㧤᦬એ㒠‫ ޔ‬ᐕߩ / ߩ࿾㔡߇ᦨᄢߢ޽ࠅ‫ޔ‬㧹㧠ࠢ࡜ࠬߩ࿾㔡߽ᤨ᛬⊒↢ߔࠆ⒟ᐲߢ޽ࠆ‫ޕ‬㗔ၞ㨎ౝߩ࿾㔡ᵴേ⚻ㆊ࿑੹࿁ߩ࿾㔡ߩ㔡ᄩ૏⟎ਃᴡ࿾㔡╙4࿑ 2008ᐕ11᦬24ᣣ ጘ㒂⋵⟤Ớ᧲ㇱߩ࿾㔡
Fig.4 The earthquake eastern part of Mino area in Gifu Prefecture on Nov. 24 2008.

- 130 -㧞᦬㧝ᣣ ⨙ၔ⋵ᴒߩ࿾㔡ࡊ࡟࡯࠻Ⴚ⇇ဳ࿾㔡‫ޔ‬/‫ᦨޔ‬ᄢ㔡ᐲ㧠㔡ᄩಽᏓ࿑㧔 ᐕ  ᦬એ㒠‫ޔ‬/҈‫ޔ‬ᷓߐ MO એᵻ㧕㧔 ᐕ㧝᦬એ㒠ߩ࿾㔡ࠍỚߊ⴫␜㧕㗔ၞ㨍㗔ၞ㨎%/6੹࿁ߩ࿾㔡㧭㧮 ᐕ㧞᦬㧝ᣣ  ᤨ  ಽߦ⨙ၔ⋵ᴒߩᷓߐ MO ߢ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧠㧕߇⊒↢ߒߚ‫⊒ޕ‬㔡ᯏ᭴ߪ⷏ർ⷏㧙᧲ධ᧲ᣇะߦ࿶ജゲࠍᜬߟㅒᢿጀဳߢ‫ޔ‬ᄥᐔᵗࡊ࡟࡯࠻ߣ㒽ߩࡊ࡟࡯࠻ߩႺ⇇ߢ⊒↢ߒߚ࿾㔡ߢ޽ࠆ‫ޕ‬૛㔡ᵴേߪ‫ޔ‬࿾㔡⊒↢ᓟᢙᤨ㑆߹ߢߪᵴ⊒ߢ޽ߞߚ߇‫ߩߘޔ‬ᓟㅢᏱߩ࿾㔡ᵴേ⁁ᘒߦᚯߞߡ޿ࠆ‫ޕ‬੹࿁ߩ࿾㔡ߩ㔡Ḯઃㄭߪ‫ ޔ‬ᐕ㧥᦬㧠ᣣߦߪ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧟㧕‫ ޔ‬ᐕ㧞᦬㧥ᣣߦߪ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧟㧕߇⊒↢ߔࠆߥߤ࿾㔡ᵴേ߇ᵴ⊒ߥ㗔ၞߢ޽ࠆ‫ޕ‬㗔ၞ㨎ౝߩ࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑㧔ߚߛߒ‫ޔ‬ᷓߐ MO㨪MO㧕%/6㗔ၞ㨍ౝߩᢿ㕙࿑㧔㧭㧙㧮ᛩᓇ㧕㧭੹࿁ߩ࿾㔡㧮㧔 ᐕ㧞᦬㧝ᣣએ㒠‫ޔ‬/҈㧕㔡ᄩಽᏓ࿑㧔 ᐕ㧤᦬એ㒠‫ޔ‬ᷓߐ MO એᵻ‫ޔ‬/҈㧕㧔 ᐕ㧝᦬એ㒠ߩ࿾㔡ࠍỚߊ⴫␜㧕੹࿁ߩ࿾㔡㗔ၞ㨏ౝߩ࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑㗔ၞ㨏 ⨙ၔ⋵ᴒ㧔㗔ၞ㨏㧕ߢߪ‫ޔ‬/ ࠍ⿥߃ࠆ࿾㔡߇⚂  ᐕߦ㧝࿁ߩഀวߢ⊒↢ߒߡ߅ࠅ‫ᦨޔ‬ㄭߢߪ  ᐕ㧡᦬㧤ᣣߦ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧡ᒙ㧕߇⊒↢ߒߡ޿ࠆ‫੹ޔߚ߹ޕ‬࿁ߩ࿾㔡ߩධ⚂ MO ߩ૏⟎ߢߪ‫ ޔ‬ᐕ㧡᦬  ᣣߦ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧡㧕߇⊒↢ߒߡ޿ࠆ‫ޕ‬㧔⴫␜ߒߡ޿ࠆ⊒㔡ᯏ᭴⸃ߪోߡ %/6 ⸃㧕╙5࿑ 2009ᐕ2᦬1ᣣ ⨙ၔ⋵ᴒߩ࿾㔡
Fig.5 The earthquake off Ibaraki Prefecture on Feb. 1 2009.

- 131 -㧞᦬ᣣ ጊ᪸⋵ਛ࡮⷏ㇱާ㕒ጟ⋵᧲ㇱިߩ࿾㔡ࡈࠖ࡝ࡇࡦᶏࡊ࡟࡯࠻ߩᴉߺㄟߺߦ઻߁࿾㔡‫ޔ‬/㔡ᄩಽᏓ࿑㧔ᐕ᦬㧝ᣣ㨪ᐕ㧞᦬ᣣ‫ޔ‬
ᷓߐMOએᵻ‫ޔ‬㪤҈㧕㧔ᐕ᦬એ㒠ߩ࿾㔡ࠍỚߊ⴫␜㧕㧭੹࿁ߩ࿾㔡㧮㨍ާިౝߪ᳇⽎ᐡ߇ᖱႎ⊒⴫ߦ↪޿ߚ㔡ᄩ࿾ฬᐕ᦬ᣣᤨಽߦጊ᪸⋵ਛ࡮⷏ㇱߩᷓߐMOߢ/ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧟㧕߇⊒↢ߒߚ‫⊒ޕ‬㔡ᯏ᭴ߪർർ⷏㧙ධධ᧲ᣇะߦ࿶ജゲࠍᜬߟㅒᢿጀဳߢ‫ࡦࡇ࡝ࠖࡈޔ‬ᶏࡊ࡟࡯࠻ߩᴉߺㄟߺߦ઻߁࿾㔡ߢ޽ࠆ‫ޕ‬ᣣ㧔ᣣߩ࿾㔡ߩ⚂㧝ᣣᓟ㧕ߦߪ/ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧝㧕߇⊒↢ߒߚ‫ࠄࠇߎޕ‬ߩ࿾㔡ߩ⊒↢೨ᓟߦ࿾㔡ᵴേ߇޽ߞߚ߇‫ޔ‬ߘࠇߙࠇᒰᣣਛߦ߶߷෼߹ߞߡ޿ࠆ‫ޕ‬੹࿁ߩ࿾㔡ߩ㔡ᄩ๟ㄝ㧔㗔ၞ㨍㧕ߩ࿾㔡ᵴേࠍ⷗ࠆߣ‫ޔ‬ධ஥߆ࠄ੹࿁ߩ࿾㔡ߩ㔡ᄩߩ޽ߚࠅߦ߆ߌߡ‫੹ޔ‬࿁ߩ࿾㔡ߣห᭽ߩ⊒㔡ᯏ᭴㧔ർർ⷏㧙ධධ᧲ᣇะߩ࿶ജゲࠍ߽ߟဳ㧕ߩ࿾㔡߇⊒↢ߒߡ޿ࠆ‫ߩࠄࠇߎޕ‬࿾㔡㧔㗔ၞ㨎ౝ㧕ߩർ஥ߢߪࡈࠖ࡝ࡇࡦᶏࡊ࡟࡯࠻ߩᴉߺㄟߺߦ઻߁ߣ⠨߃ࠄࠇࠆ࿾㔡߇⷗ࠄࠇߥ޿‫ޕ‬ᐕ᦬એ㒠‫੹ޔ‬࿁ߩ࿾㔡ߩ㔡Ḯઃㄭ㧔㗔ၞ㨎㧕ߢߪ‫ޔ‬ᐕ᦬ᣣߦ/ߩ࿾㔡 ᦨᄢ㔡ᐲ㧟 ߥߤ‫ޔ‬/એ਄ߩ࿾㔡߇ᤨ‫ޕࠆ޿ߡߒ↢⊒ޘ‬᧲ᶏ࿾㔡ߩᗐቯ㔡Ḯၞ㧭㗔ၞ㨍ౝߩᢿ㕙࿑㧔㧭㧙㧮ᛩᓇ㧕㧮㗔ၞ㨎ౝߩ㧹㧙㨀࿑‫ޔ‬࿁ᢙⓍ▚࿑㨎੹࿁ߩ࿾㔡㧔ᐕ㧞᦬ᣣ㨪ᣣ‫ޔ‬㧹ߔߴߡ㧕

╙6࿑ 2009ᐕ2᦬16ᣣ ጊ᪸⋵ਛ࡮⷏ㇱߩ࿾㔡
Fig.6 The earthquake in the middle western part of Yamanashi Prefecture on Feb. 16 2009.

- 132 -㧞᦬  ᣣ ජ⪲⋵ධㇱߩ࿾㔡ࡈࠖ࡝ࡇࡦᶏࡊ࡟࡯࠻ౝㇱߩ࿾㔡‫ޔ‬ᱜᢿጀဳ‫ޔ‬/‫ᦨޔ‬ᄢ㔡ᐲ㧠㔡ᄩಽᏓ࿑㧔 ᐕ  ᦬એ㒠‫ޔ‬ᷓߐ 㨪MO‫ޔ‬/҈㧕㧔 ᐕ㧞᦬㧝ᣣએ㒠ߩ࿾㔡ࠍỚߊ⴫␜㧕  ᐕ㧞᦬  ᣣ  ᤨ  ಽߦජ⪲⋵ධㇱߩᷓߐ MO ߢ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧠㧕߇⊒↢ߒߚ‫ߩߎޕ‬࿾㔡ߩ⊒㔡ᯏ᭴ߪ⷏ർ⷏̆᧲ධ᧲ᣇะߦᒛജゲࠍᜬߟᱜᢿጀဳߢ‫ࡦࡇ࡝ࠖࡈޔ‬ᶏࡊ࡟࡯࠻ߩౝㇱߢ⊒↢ߒߚ࿾㔡ߣ⠨߃ࠄࠇࠆ‫ޕ‬૛㔡ᵴേߪૐ⺞ߢ޽ࠆ‫ޕ‬੹࿁ߩ࿾㔡ߩ㔡Ḯઃㄭ㧔㗔ၞ㨏㧕ߪ‫ޔ‬/ ೨ᓟߩ࿾㔡߇ᐕ㧞㧟࿁⒟ᐲߢ⊒↢ߒߡ߅ࠅ‫ޔ‬ᤨ‫ߚߞ߹ߣ߹ޘ‬࿾㔡ᵴേ߇ߺࠄࠇࠆߣߎࠈߢ‫ޔ‬ᦨㄭߢߪ  ᐕ㧤᦬ߦ /‫ᦨޔ‬ᄢ㔡ᐲ㧠ߥߤߩ࿾㔡ᵴേ߇⊒↢ߒߡ޿ࠆ‫ޕ‬੹࿁ߩ࿾㔡㗔ၞ㨎㗔ၞ㨏ౝߩ࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑㗔ၞ㨍㗔ၞ㨍ౝߩᢿ㕙࿑㧔ධർᣇะᛩᓇ㧕㗔ၞ㨏ർ㗔ၞ㨎ౝߩᢿ㕙࿑㧔᧲⷏ᣇะᛩᓇ㧕੹࿁ߩ࿾㔡੹࿁ߩ࿾㔡ධ᧲⷏㔡ᄩಽᏓ࿑㧔 ᐕ㧤᦬એ㒠‫ޔ‬ᷓߐ 㨪MO‫ޔ‬/҈㧕  ᐕ㧤᦬એ㒠ߩᵴേࠍ⷗ࠆߣ‫੹ޔ‬࿁ߩ࿾㔡ߩ㔡ᄩઃㄭ㧔㗔ၞ㨏㧕ߢߪ‫ޔ‬/ એ਄ߩ࿾㔡߇ᤨ‫ᦨޕࠆ޿ߡߒ↢⊒ޘ‬ᄢߩ࿾㔡ߪ  ᐕ  ᦬ ᣣߩ / ߩ࿾㔡㧔ࡈࠖ࡝ࡇࡦᶏࡊ࡟࡯࠻ౝㇱߩ࿾㔡㧕ߢ޽ࠅ‫ߩߎޔ‬࿾㔡ߢߪᱫ⠪㧞ฬߥߤߩⵍኂ߇޽ߞߚ㧔‫ᦨޟ‬ᣂ ᣣᧄⵍኂ࿾㔡✚ⷩ‫ޠ‬ߦࠃࠆ㧕‫ޕ‬㗔ၞ㨐ౝߩ࿾㔡ᵴേ⚻ㆊ࿑੹࿁ߩ࿾㔡ߩ㔡ᄩ૏⟎‫ڎ‬㗔ၞ㨐╙7࿑ 2009ᐕ2᦬17ᣣ ජ⪲⋵ධㇱߩ࿾㔡
Fig.7 The earthquake in the southern part of Chiba Prefecture on Feb. 17 2009.

- 133 -㧞᦬  ᣣ ጘ㒂⋵⟤Ớਛ⷏ㇱާ⑔੗⋵Ꭸർިߩ࿾㔡࿾Ზౝߩ࿾㔡‫ޔ‬ᮮߕࠇᢿጀဳ‫ޔ‬/‫ᦨޔ‬ᄢ㔡ᐲ㧠㔡ᄩಽᏓ࿑㧔 ᐕ  ᦬એ㒠‫ޔ‬/҈‫ޔ‬ᷓߐ MO એᵻ㧕 ᐕ㧞᦬㧝ᣣએ㒠ࠍỚߊ⴫␜ާިౝߪ᳇⽎ᐡ߇ᖱႎ⊒⴫ߦ↪޿ߚ㔡ᄩ࿾ฬ ᐕ㧞᦬  ᣣ  ᤨ  ಽߦጘ㒂⋵⟤Ớਛ⷏ㇱާ⑔੗⋵Ꭸർިߩᷓߐ㧥MO ߢ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧠㧕߇⊒↢ߒߚ‫⊒ޕ‬㔡ᯏ᭴ߪ⷏ർ⷏̆᧲ධ᧲ᣇะߦ࿶ജゲࠍᜬߟᮮߕࠇᢿጀဳߢ‫ޔ‬࿾Ზౝߢ⊒↢ߒߚ࿾㔡ߢ޽ࠆ‫ᧄޕ‬㔡⊒↢⋥ᓟߩ૛㔡ᵴേߪᵴ⊒ߛߞߚ߇‫ߩߘޔ‬ᓟ⑔੗⋵੹࿁ߩ࿾㔡 ߪᰴ╙ߦ෼߹ࠅߟߟ޽ࠆ‫ޕ‬૛㔡߇᧲ർ᧲̆⷏ධ⷏ᣇะߦ߶߷㋦⋥ߦಽᏓߒߡ޿ࠆߎߣߣ⊒㔡ᯏ᭴⸃߆ࠄ‫੹ޔ‬࿁ߩ࿾㔡ߪฝᮮߕࠇᢿጀဳߢᵴേߒߚߣ⠨߃ࠄࠇࠆ‫੹ޕ‬࿁ߩ࿾㔡ߩ㔡ጘ㒂⋵Ḯઃㄭ㧔㗔ၞ㨍㧕ߢߪ‫ ޔ‬ᐕ  ᦬એ㒠‫ޔ‬߶ߣࠎߤ࿾㔡ߪ⊒㗔ၞ㨍ౝߩᢿ㕙࿑↢ߒߡ޿ߥ߆㧔㧭㧙㧮ᛩᓇ㧕ℚℛḓߞߚ‫ޕ‬㧭㧮߹ߚ‫੹ޔ‬࿁ߩ࿾㔡ߩධ᧲⚂ MO ߩṑ⾐⋵૏⟎㧔㗔ၞ㨎㧕ߢ‫ޔ‬੹࿁ߩ࿾㔡㧞᦬  ᣣߩ /਄࿑⍱ᒻ㗔ၞ᜛ᄢ࿑ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧔 ᐕ㧞᦬  ᣣએ㒠‫ޔ‬/҈㧕㧟㧕ࠍᦨᄢߣߔࠆዊⷙᮨߥ࿾㔡ᵴേ߇޽ߞߚ‫ޕ‬੹࿁ߩ࿾㔡㗔ၞ㨍ᄥታ✢࡮ὐ✢ߪ‫ޟ‬ᣂ✬ᣣᧄߩ ᵴ ᢿ ጀ ‫ޠ‬㧔ᵴᢿጀ⎇ⓥળ✬㧘㧕ߦࠃࠆᵴᢿጀߩ૏⟎ࠍ␜ߔ㗔ၞ㨍ౝߩ࿾㔡ᵴേ⚻ㆊ࿑㧔 ᐕ  ᦬એ㒠‫ޔ‬㧹҈㧕㧭㧮㗔ၞ㨎࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑㧔㧞᦬  ᣣએ㒠‫ޔ‬㧹҈㧕㔡ᄩಽᏓ࿑㧔 ᐕએ㒠‫ޔ‬/҈‫ޔ‬ᷓߐ MO એᵻ㧕㧔 ᐕ㨪 ᐕ㧣᦬߹ߢߪቝᵤߩ࿾㔡ࠞ࠲ࡠࠣߦࠃࠆ㧕㗔ၞ㨏㗔ၞ㨎ౝߩ࿾㔡ᵴേ⚻ㆊ࿑㧔 ᐕ㧞᦬એ㒠㧕੹࿁ߩ࿾㔡Ớየ࿾㔡 ੹࿁ߩ࿾㔡ߩ㔡ᄩઃㄭ㧔㗔ၞ㨏㧕ߢߪ‫ ޔ‬ᐕߦỚየ࿾㔡/ ߇⊒↢ߔࠆߥߤ‫ ޔ‬ᐕઍ߆ࠄ  ᐕઍߦ߆ߌߡ࿾㔡ᵴേ߇ᵴ⊒ߢ޽ߞߚ‫ᦨޕ‬ㄭߢߪ / ࠍ⿥߃ࠆ࿾㔡ߪᤨ᛬⊒↢ߒߡ޿ࠆ߇‫ ޔ‬ᐕߩ / ߩ࿾㔡⊒↢એ㒠‫ޔ‬/ એ਄ߩ࿾㔡ߪ⊒↢ߒߡ޿ߥ޿‫ޕ‬

╙8࿑(a) 2009ᐕ2᦬18ᣣ ጘ㒂⋵⟤Ớਛ⷏ㇱߩ࿾㔡
Fig.8(a) The earthquake middle western part of Mino area in Gifu Prefecture on Feb. 18 2009.

- 134 -㧞᦬  ᣣ ጘ㒂⋵⟤Ớਛ⷏ㇱߩ࿾㔡
㧔㧰㧰ᴺߦࠃࠆ㔡ḮಽᏓߩ․ᓽԘ㧕᷹ⷰὐ㒢ቯߩ㓙ߦ↪޿ߚ᷹ⷰὐಽᏓ࿑ ᷹ⷰὐ㒢ቯ㧗᷹ⷰὐ⵬ᱜࠍ߆ߌߚ㔡Ḯࠍೋᦼ୯ߣߒ‫ޔ‬ᵄᒻ⋧㑐ࠍ↪޿ߚ㧰㧰ᴺߢ㔡Ḯౣ⸘▚ࠍⴕߞߚ‫ߩߘޕ‬⚿ᨐ‫৻ޔ‬రൻ㔡ḮߣᲧߴ‫ోޔ‬૕⊛ߦ߹ߣ߹ߞߚಽᏓߣߥߞߡ߅ࠅ‫߷߶ޔ‬㋦⋥ߥ㔡ḮಽᏓࠍ⷗ࠆߎߣ߇ߢ߈ࠆ‫ޕ‬ᧄ㔡ᧄ㔡ᧄ㔡ᧄ㔡ᦨᄢ૛㔡ᦨᄢ૛㔡ᦨᄢ૛㔡ᦨᄢ૛㔡৻రൻ㔡Ḯ㧰㧰ᴺߦࠃࠆ㔡Ḯᧄ㔡ᦨᄢ૛㔡ᦨᄢ૛㔡ᧄ㔡╙8࿑(b) ߟߠ߈㧔DDᴺߦࠃࠆ㔡ḮಽᏓߩ․ᓽ㧕
Fig.8(b) Continued (the hypocenter distribution by Double-Difference method).

- 135 -㧞᦬  ᣣ ጘ㒂⋵⟤Ớਛ⷏ㇱߩ࿾㔡㧔㧰㧰ᴺߦࠃࠆ㔡ḮಽᏓߩ․ᓽԙ㧕zz
㧰㧰ᴺߦࠃࠆ㔡Ḯzz㨍㨎㨏㨐ᧄ㔡㗔ၞ㨍ߢߪධ᧲㜞ⷺ௑ᢳߩ૛㔡ಽᏓ߇⷗ࠄࠇ‫ᧄޔ‬㔡෸߮ᦨᄢ૛㔡ߩ⊒㔡ᯏ᭴⸃ߩ▵㕙ߩ  ߟ㧔ධ᧲㜞ⷺ௑ᢳߩฝᮮߕࠇᢿጀ㧕ߣ৻⥌ߔࠆ‫ޕ‬㗔ၞ㨎ߢߪ‫ޔ‬㗔ၞ㨍ߣห᭽ߦධ᧲㜞ⷺ௑ᢳߩ૛㔡ಽᏓ߇⷗ࠄࠇࠆߣหᤨߦ‫ޔ‬૛㔡ಽᏓߩᷓ޿ㇱಽߦ߅޿ߡ‫ߘޔ‬ߩ૛㔡ಽᏓߣ㋦⋥ߥಽᏓ㧔ർ⷏ૐⷺ௑ᢳ㧕߇⷗ࠄࠇࠆ‫ޔߚ߹ޕ‬૛㔡࿁ᢙ߇৻⇟ᄙ޿‫ޕ‬ᧄ㔡ࠍ฽߻㗔ၞ㨏ߢߪ‫ޔ‬૛㔡߇ዋߥߊ‫ߩ⁁✢ߚߒߣࠅ߈ߞߪޔ‬૛㔡ಽᏓࠍ⷗ࠆߎߣ߇ߢ߈ߥ޿߇‫ᧄޔ‬㔡ߪධ᧲㜞ⷺ௑ᢳߩ૛㔡ಽᏓ߆ࠄዋߒᄖࠇߡ޿ࠆࠃ߁ߦ⷗߃ࠆ㧔♖ᐲ਄ߩ໧㗴㧫㧕‫ޕ‬ᦨᄢ૛㔡 / ࠍ฽߻㗔ၞ㨐ߢߪ‫ޔ‬૛㔡࿁ᢙߪᒰೋዋߥ߆ߞߚ߇‫ᦨޔ‬ᄢ૛㔡ߩ⊒↢ᓟ‫ޔ‬ዋߒᵴ⊒ߦߥߞߚߎߣ߇ಽ߆ࠆ㧔ઁߩ㗔ၞߢߪ⷗ࠄࠇߥ޿㧕‫ޕ‬૛㔡ಽᏓߪ߶߷㋦⋥ߣߥߞߡ޿ࠆ‫ޕ‬ᢿ㕙࿑㨍㨎㨏㨐ᦨᄢ૛㔡ᢿ㕙࿑㧔ో㗔ၞ㧕ᧄ㔡ᦨᄢ૛㔡ᦨᄢ૛㔡ᧄ㔡࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑

╙8࿑(c) ߟߠ߈
Fig.8(c) Continued.

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╙9࿑ 2009ᐕ2᦬24ᣣ ᣂẟ⋵ਛ⿧࿾ᣇߩ࿾㔡Fig.9 The earthquake in Chuetsu region, Niigata Prefecture on Feb. 24 2009.

- 137 -㧠᦬  ᣣ ⨙ၔ⋵ᴒߩ࿾㔡ࡊ࡟࡯࠻Ⴚ⇇ဳ࿾㔡‫ޔ‬ㅒᢿጀဳ‫ޔ‬/㔡ᄩಽᏓ࿑㧔 ᐕ  ᦬એ㒠‫ޔ‬ᷓߐ 㨪MO‫ޔ‬/҈㧕 ᐕ  ᦬એ㒠ߩ㔡ḮࠍỚߊ⴫␜‫⊒ޕ‬㔡ᯏ᭴⸃ߪోߡ %/6 ⸃‫ޕ‬㗔ၞ㨍㧭੹࿁ߩ࿾㔡㧮 ᐕ㧠᦬  ᣣ  ᤨ  ಽߦ⨙ၔ⋵ᴒߩᷓߐ MO ߢ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧟㧕߇⊒↢ߒߚ‫⊒ޕ‬㔡ᯏ᭴㧔%/6 ⸃㧕ߪ‫ޔ‬⷏ർ⷏㧙᧲ධ᧲ᣇะߦ࿶ജゲࠍᜬߟㅒᢿጀဳߢ‫ޔ‬ᄥᐔᵗࡊ࡟࡯࠻ߣ㒽ߩࡊ࡟࡯࠻ߩႺ⇇ߢ⊒↢ߒߚ࿾㔡ߢ޽ࠆ‫੹ޕ‬࿁ߩ㔡Ḯߪࡊ࡟࡯࠻Ⴚ⇇ઃㄭߩ࿾㔡ᵴേ߇ᵴ⊒ߥ㗔ၞߩਛߦ૏⟎ߒ‫ޔ‬ઃㄭߢߪ /એ਄ߩ࿾㔡߇ᤨ‫ᦨޕࠆ޿ߡߒ↢⊒ޘ‬ㄭߢߪ‫ ޔ‬ᐕ  ᦬  ᣣߦ / ߩ࿾㔡㧔ᦨᄢ㔡ᐲ㧡ᒙ㧕߇⊒↢ߒ‫⨙ޔ‬ၔ⋵ߣජ⪲⋵ߢ⽶்⠪ฦ㧝ฬߩⵍኂ߇↢ߓߚ㧔✚ോ⋭ᶖ㒐ᐡߦࠃࠆ㧕‫ޕ‬㗔ၞ㨎ౝߩ࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑㗔ၞ㨍ౝߩᢿ㕙࿑㧔㧭㧙㧮ᛩᓇ㧕㧭੹࿁ߩ࿾㔡㧮㗔ၞ㨎㧔 ᐕ  ᦬એ㒠‫ޔ‬/҈㧕㔡ᄩಽᏓ࿑㧔 ᐕ㧤᦬એ㒠‫ޔ‬ᷓߐ 㨪MO‫ޔ‬/҈㧕 ᐕ㧤᦬એ㒠‫੹ޔ‬࿁ߩ㔡ᄩ๟ㄝߢߪ‫ޔ‬/એ਄ߩ࿾㔡߇ᤨ‫ ޕࠆ޿ߡߒ↢⊒ޘ‬ᐕ  ᦬ 
ᣣߦߪ / ߩ࿾㔡߇⊒↢ߒ‫ޔ‬ߎߩ࿾㔡ߦࠃࠅᵤᵄࠍ᷹ⷰ㧔ᬌầᚲߦ߅ߌࠆᦨᄢߩ㜞ߐዊฬᵿ EO㧕ߔࠆߣߣ߽ߦ‫⑔ޔ‬ፉ⋵ߣ⨙ၔ⋵ߢᑪ‛╬ߦⵍኂ߇ᣣᧄⵍኂ࿾㔡✚ⷩ‫ࠆࠃߦޠ‬㧕‫ޕ‬↢ߓߚ㧔‫ᦨޟ‬ᣂ㗔ၞ㨏ౝߩ࿾㔡ᵴേ⚻ㆊ࿑‫ޔ‬࿁ᢙⓍ▚࿑੹࿁ߩ࿾㔡㗔ၞ㨏⿒ὐ✢ᨒߪ࿾㔡⺞ᩏᆔຬળߩ㐳ᦼ⹏ଔߦࠃࠆ‫⨙ޟ‬ၔ⋵ᴒߩ৻ㅪߩ࿾㔡‫ߩޠ‬ᗐቯ㔡Ḯၞ㧔ὐ✢ᨒߩ็߈಴ߒߪ‫ޔ‬‫⨙ޟ‬ၔ⋵ᴒߩ৻ㅪߩ࿾㔡‫ߦޠ‬฽߹ࠇࠆߎߣࠍ⴫ߔ㧕‫ޕ‬╙10࿑ 2009ᐕ4᦬28ᣣ ⨙ၔ⋵ᴒߩ࿾㔡Fig.10 The earthquake off Ibaraki Prefecture on April 28 2009.

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