東北地域災害科学研究179

第55巻（2019）⚟ᓥ┴ࡢᗈᖏᇦࣜࢽ࢔࢔ࣞ࢖࡛ほᖖ᫬ᚤືࡢᆅ㟈Ἴᖸ΅ἲゎᯒ̿༡໭ࡉࢀࡓ⥺࡟࠾ࡅࡿゎᯒ̿ ᒾᡭ኱ᏛᕤᏛ㒊 ㉳⏣㈼ぶᒾᡭ኱Ꮫ⌮ᕤᏛ㒊 ᒣᮏⱥ࿴ 㰺⸨๛1.ࡣࡌࡵ࡟ ᡃࠎࡣ⚟ᓥ┴ࡢ┤ୗ࡛Ⓨ⏕ࡍࡿࢫ࣮ࣉࣛࢫࣛࣈᆅ㟈(౛࠼ࡤ㸪Uchida et al, 2010)࡜࿧ࡤࢀࡿᆅ
㟈ࡢⓎ⏕࣓࢝ࢽࢬ࣒ࢆゎ᫂ࡍࡿࡓࡵ㸪2012 ᖺᗘ࠿ࡽ(බ㈈)ᆅ㟈ண▱⥲ྜ◊✲᣺⯆఍࡛タ⨨ࡉࢀࡓᗈᖏᇦᆅ㟈ィࣜࢽ࢔࢔ࣞ࢖࡟ࡼࡾ 2014 ᖺࡲ࡛ᮾすࡁࡓࠋబ⸨࡯࠿(2017)࡛ࡣᮾす⥺ࡢ 10 Ⅼࡢほ⥺㸦10 ྎ㸧ࡢᆅ㟈࣭ᚤືほࢆ⾜ࡗ࡚Ⅼ࡟ᑐࡋ㸪1 ࢝᭶㔜ྜ┦஫┦㛵㛵ᩘࢆィ⟬ࡋ㸪⩌㏿ᗘࡢ⟬ᐃࢆ⾜ࡗࡓࠋࡲࡓ㸪Takagi et al.(2014)ࡢᡭἲࢆ⏝࠸࡚⾲㠃Ἴࡢศ㞳ࢆ⾜ࡗࡓ⤖ᯝ㸪ᮾす⥺ࡢほࡏ఩⨨ࡢ㏆࠸ほ⤖ᯝ࡛ࡣ⾲㠃Ἴࡀ༟㉺ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡓࠋࡉࡽ࡟ࣜࢽ࢔࢔ࣞ࢖ࡢ⤌ࡳྜࢃⅬ㛫ࡢ⩌㏿ᗘ࡜௜㏆ࡢ Hi-net ࡢほグ㘓࡛ᚓࡽࢀࡿ⩌㏿ᗘࡢẚ㍑ࢆ⾜ࡗࡓ࡜ࡇࢁ㸪್ࡀྠ➼࡟࡞ࡿࡇ࡜࠿ࡽࣜࢽ࢔グ㘓࡟ᆅ㟈Ἴᖸ΅ἲゎᯒࢆ㐺⏝ࡋ㸪ὸ㒊ࡢᵓ㐀ࢆ᥎ᐃࡍࡿᡭἲࡀ᭷ຠ࡛࠶ࡿ࡜ุ᩿ࡉࢀࡓࠋ௒ᅇࡣᆅ㟈ண▱⥲ྜ◊✲᣺⯆఍࡟ࡼࡾ᪂ࡓ࡟タ⨨ࡉࢀ㸪2014 ᖺ࠿ࡽ 2015 ᖺࡲ࡛ࡢ⣙ 6 ࢝᭶ほࡉࢀࡓ 4 Ⅼࡢ༡໭⥺ࡢゎᯒࢆ⾜ࡗࡓࠋ༡໭⥺࡟ຍ࠼㸪௜㏆ࡢ Hi-netࠊF-net ࡢほグ㘓ࡶ⏝࠸࡚ 3 ᡂศ┦஫┦㛵㛵ᩘࢆィ⟬ࡋ㸪⩌㏿ᗘࡢ⟬ᐃࢆ⾜ࡗࡓࠋࡲࡓ㸪Takagi et al.(2014)ࡢᡭἲ
ࢆ⏝࠸࡚⾲㠃Ἴࡢศ㞳ࢆ⾜࠸㸪Nishida et al.(2008)ࡢ㏿ᗘᵓ㐀ࣔࢹࣝ࠿ࡽィ⟬ࡋࡓࣞ࢖࣮ࣜἼ㸪ࣛࣈἼ࡜ࡢẚ㍑ࢆ⾜࠸㸪ᚓࡽࢀࡓ⤖ᯝࡢጇᙜᛶࢆ᳨ウࡋࡓࠋᗈᇦࣜࢽ࢔࢔ࣞ࢖ほ ༡໭⥺ࡣᆅ㟈ண▱⥲ྜ◊✲᣺⯆఍࡟ࡼࡾタ⨨ࡉࢀࡓ 4 Ⅼ࡜ F-net ᗈ㔝(N.HROF)ࡢ
ィ 5 Ⅼࡢ

⥺࡜ࡋ㸪ᗈ㔝࠿ࡽ༡࡟ྥ࠿ࡗ࡚

㡰࡟␒ྕࢆ᣺ࡗࡓࠋࢭࣥࢧ࣮ࡣᅛ᭷࿘ᮇ
120 ⛊ 3 ᡂศ㏿ᗘィ(Trillium Compact)ࢆ౑
⏝ࡋ㸪཰㘓࡟ࡣࢹ࣮ࢱ࣮ࣟ࢞LS8800 ࢆ౑⏝ࡋࡓࠋࢧࣥࣉࣜࣥࢢ࿘Ἴᩘ 100Hz ࡛ほࡈ࡜⊂❧࡟㐃⥆Ⅼᐃࡉࢀࡓࠋᗈ㔝ࡢ࡯࠿࡟ཧ↷Ⅼ࡜ࡋ࡚ F-net ඵ⁁(N.YMZF)࡜ Hi-net
࠸ࢃࡁす(N.IWWH)ࢆ౑⏝ࡋࡓࠋᅗ 1 ࡟௒ᅇ౑⏝ࡋࡓほ⨨ࢆ♧ࡍࠋⅬ఩⨨࡜ Hi-net㸪F-net ࡢ఩ᅗ 1 ༡໭⥺ࡢほⅬ఩⨨࡜౑⏝ࡋࡓHi-net, F-net ఩⨨ ࡣ༡໭⥺㸪 ࡣᮾす ࡣ Hinet㸪 ⥺

ࡣ F-net*Seismic interferometry analysis of microtrenors observed in a lineae array with broadband seismometers inFukushima Prefecture by K. Okita, H. Yamamoto and T. Saito180┦஫┦㛵㛵ᩘࡢ⟬ᐃ ほࢹ࣮ࢱࡸྲྀᚓࡋࡓ Hi-net㸪F-net ࡢほグ㘓ࡣ 100Hz ࡛ࢧࣥࣉࣜࣥࢢࡉࢀ࡚࠸ࡿࡀ㸪ࢹ࣮ࢱ㔞ࡀ⭾኱࡛࠶ࡿࡓࡵィ⟬᫬㛫ࢆ▷⦰ࡍࡿࡓࡵἼᙧࢹ࣮ࢱࢆ 20Hz ࡟ࣜࢧࣥࣉࣜࣥࢢࡋࡓࠋࣜࢧࣥࣉࣜࣥࢢࢆ⾜ࡗࡓࢹ࣮ࢱ࡟ᑐࡋ㸪᫬㛫㡿ᇦ࡟࠾ࡅࡿᕧ኱ᆅ㟈ࡸ㠀ᐃᖖ㞧㡢࡟ࡼࡿ᣺ᖜࡢ஘ࢀࢆྲྀࡾ㝖ࡃࡓ
ࡵ 1 ⛊ࡢ᫬㛫つ᱁໬㸪ྠ᫬࡟஧್໬ࢆ⾜࠸㸪ࡉࡽ࡟࿘Ἴᩘ㡿ᇦ࡛つ᱁໬ࡍࡿࡓࡵ࡟࣍࣡࢖ࢺࢽࣥࢢࢆ๓ฎ⌮࡜ࡋ࡚⾜ࡗࡓ㸦౛࠼ࡤ㸪Bensen et al.,2007㸧ࠋほグ㘓ࡣ᣺⯆఍ࡢᆅ㟈ィ࡟ࡼࡿࡶࡢ㸪Hi-net㸪F-net ࡢ 3 ࡘࡀ࠶ࡿࡀ௒ᅇᶵჾ⿵ṇࡣ⾜ࢃ࡞࠿ࡗࡓࠋ๓ฎ⌮ࢆ⾜ࡗࡓἼᙧ࡟ᑐࡋ FFT ฎ⌮࡟ࡼࡾࢡࣟࢫࢫ࣌ࢡࢺࣝࢆ⟬ฟࡋ㸪㏫ࣇ㸫࢚ࣜኚ᥮࡟ࡼࡾ┦஫┦㛵㛵ᩘࢆィ⟬ࡋࡓࠋ┦஫┦㛵㛵ᩘィ⟬࡟ࡣ

ᅗ 2 NS-2, NS-3 㛫ࡢ㔜ྜ┦஫┦㛵㛵ᩘ vertical ᪉ྥࡢᮇ㛫ࡈ࡜ࡢẚ㍑

᪥㔝㸦2010㸧ࡢࢫ࣌ࢡࢺࣝゎᯒࡢࣉࣟࢢ࣒ࣛࢆཧ⪃࡟ࡋࡓࠋᇶᮏ༊㛫 15ศࡢ┦஫┦㛵㛵ᩘࢆ 4 ಶᖹᆒࡋ୍࡚᫬㛫㔜ྜ┦஫┦㛵㛵ᩘ࡜ࡋ࡚⟬ฟࡋࡓࠋᶵჾࡢ୙ලྜࡸࣂࢵࢸ࣮ࣜ஺᥮➼࡛グ㘓ࡀᩘศ࠿ࡽᩘ᫬㛫㏵⤯࠼ࡿ᫬㛫ᖏࡀ࠶ࡗࡓ᪥௜ࡣ㝖࠸ࡓ࠺࠼࡛
1 ࢝᭶࡜ࡋࡓࠋ㔜ྜࡍࡿᮇ㛫ࡀ㛗࠸࡯࡝ࣀ࢖ࢬࡀᑠࡉࡃ㸪≉ᚩⓗ࡞఩┦ࢆ☜ㄆࡍࡿࡇ࡜ࡀ࡛ࡁࡿⅭ㸪౑⏝ྍ⬟࡞ 6 ࢝᭶ࡢ㔜ྜࢆ⾜ࡗࡓࠋᅗ 2 ࡟ẚ㍑ࡢࡓࡵ㔜ྜᮇ㛫ࢆ 1 ᫬㛫㸪1 ᪥㸪
10 ᪥㸪1 ࢝᭶㸪6 ࢝᭶࡜ࡋࡓ┦஫┦

ᅗ 3 NS-1 ࠿ࡽྛ㛵㛵ᩘࢆ♧ࡍࠋᅗ࠿ࡽࡣᮇ㛫ࡀ㛗࠸  vertical ᪉ྥ㸪transverse ᪉ྥⅬ࡬ࡢ 6 ࢝᭶㔜ྜ┦஫┦㛵㛵ᩘ࡯࡝≉ᚩⓗ࡞఩┦ࡀぢ࠼ࡿࡇ࡜ࢆ☜ㄆ࡛ࡁࡓࠋ
Vertical(ZZ)┦㛵㛵ᩘ࡜ Transverse(TT)┦㛵㛵ᩘࡢẚ㍑ࢆ⾜ࡗࡓࠋᅗ 3 ࡟ NS-1 ࠿ࡽྛⅬ࡬ィ⟬ࡋࡓ┦㛵㛵ᩘ ZZ㸪TT ࢆ♧ࡍࠋ㐜ࢀ᫬㛫ࢆẚ㍑ࡍࡿ࡜ TT ࡢ᪉ࡀࢃࡎ࠿࡟㏿ࡃ᳨ฟࡉࢀ࡚࠸
ࡿࡇ࡜ࡀศ࠿ࡿࠋ

181

⩌㏿ᗘࡢ⟬ᐃᚓࡽࢀࡓ┦஫┦㛵㛵ᩘ࡟ᑐࡋ(a)࡚ Dziewonski et al.(1969 ࡢ࣐(b)ࣝࢳࣉࣝࣇ࢕ࣝࢱゎᯒࢆ⾜࠸㸪⩌㏿ᗘࡢ⟬ᐃࢆ⾜ࡗࡓࠋ┦஫┦㛵㛵ᩘ࡟⊃ᖏᇦࡢࣂࣥࢻࣃࢫࣇ࢕ࣝࢱࢆ࠿ࡅࠊἼᙧࡢໟ⤡⥺ࡢ᭱኱್࠿ࡽ㐜ࢀ᫬㛫ࢆ⟬ᐃࡋ㸪ᆅ㟈ィ㛫㊥㞳ࢆ᫬㛫㐜ࢀ࡛㝖ࡍࡇ࡜࡛࿘Ἴᩘࡈ࡜
ࡢ⩌㏿ᗘࢆồࡵࡓࠋྠ᫬࡟ࢩ
ࢢࢼࣝࢆࣀ࢖ࢬ࡛㝖ࡍࡇ࡜࡟ࡼࡾ SN ẚࢆ࿘ᮇࡢ㛵ᩘ࡜ࡋ࡚⟬ฟࡋ㸪⩌㏿ᗘࡢホ౯࡟⏝࠸ࡓࠋヲࡋ࠸ィ⟬᪉ἲ࡟ࡘ࠸
࡚ࡣబ⸨࡯࠿(2017)࡟ᚑ࠺ࠋ
௒ᅇࡣ SN ẚ 10 ௨ୖࢆᇶ‽࡜ࡋ࡚⩌㏿ᗘࡢಙ㢗ᛶࢆホ౯ࡋࡓࠋ
ᅗ 4 ࡟ Vertical ᪉ྥࡢ 6 ࢝᭶㔜ྜ┦஫┦㛵㛵ᩘࡼࡾ⟬ᐃࡋࡓ⩌㏿ᗘ࡜ SN ẚࢆ♧ࡍࠋ௒ᅇࡣᶵჾ⿵ṇࢆ⾜ࡗ࡚࠸࡞࠸ࡓࡵ㸪F-net ࡛࠶ࡿ NS-1 ࡜᣺⯆఍ࡢᆅ㟈ィࢆ౑⏝ࡋࡓ࡯
࠿ࡢⅬ࡜࡛ࡣࣇ࢕ࣝࢱࣜࣥࢢ
ࡀࡇ࡜࡞ࡿྍ⬟ᛶࡀ⪃࠼ࡽࢀࡿࠋࡑࡢࡓࡵ࠿ẚ㍑ⓗ㊥㞳ࡀ㏆࠸ 1-2 ࡢ⩌㏿ᗘࡣࣉࣛࢫ᪉

ᅗ 4 Vertical ᪉ྥࡢ 6 ࢝᭶㔜ྜ┦஫┦㛵㛵ᩘࡼࡾ⟬ᐃࡋࡓྥ࡜࣐࢖ࢼࢫ᪉ྥ࡛ࢃࡎ࠿࡟

⩌㏿ᗘ࡜ SN ẚ␗࡞ࡗ࡚࠸ࡓࠋ2-3 ࡛ࡢ⩌㏿(a)ࡣ⩌㏿ᗘ㸪(b)ࡣ SN ẚࢆ♧ࡍᗘࡣ SN ẚࡀࣆ࣮ࢡࢆ࡜ࡿ࿘
Ἴᩘ 0.5Hz ⛬ᗘ௨ୖ࠿ࡽࡣࣉࣛࢫ᪉ྥ࡜࣐࢖ࢼࢫ᪉ྥ࡛࡯ࡰ୍⮴ࡋ㸪ࡲࡓ⣙ 2.2km/s ୍࡛ᐃࡢ್ࢆ࡜ࡗ࡚࠸ࡓࠋ࿘Ἴᩘ࡟ࡼࡗ࡚㏿ᗘࡀኚ໬ࡋ࡚࠸࡞࠸ࡢ࡛ࡇࡇ࡛ࡣᐇయἼ࡛࠶ࡿྍ⬟ᛶࡀ⪃࠼ࡽࢀࡿࠋNS-5 ࡜ࡢ⤌ࡳྜࢃࡏ࡛ࡣศᩓ᭤⥺ࡢ㐃⥆ᛶࡀప࠸ࡇ࡜ࡀ☜ㄆ࡛ࡁࡓ୍᪉࡛㸪NS-5࡜᭱ࡶ㏆࠸⤌ࡳྜࢃࡏ࡛࠶ࡿ 4-5 ࡣ௚࡜ẚ㍑ࡋ࡚㐃⥆ᛶࡀ㧗ࡃ㸪⩌㏿ᗘࡣ⣙ 1km/s ࡲ࡛పୗࡋ
࡚࠸ࡓࠋࡇࢀࡽࡢ⤖ᯝ࠿ࡽ NS-2㸪NS-3㸪NS-4 ௜㏆ࡢᆅୗᵓ㐀ࡣ㏆࠸ࡶࡢ࡛࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋ
ࡲࡓ㸪NS-5 ࡣศᩓ᭤⥺ࡢ㐃⥆ᛶࡀప࠸୰㸪NS-4 ࡜ࡢ⤌ࡳྜࢃࡏ࡛㐃⥆ⓗ࡟⩌㏿ᗘࡀపୗࡍࡿ

182

ࡇ࡜࠿ࡽ㸪NS-4 ࡜ NS-5 ࡢ㛫࡛ᆅୗᵓ㐀ࡀኚ໬ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋᐇ㝿࡟ NS-5 ௜㏆ࡣᖹ㔝㒊࡛࠶ࡾ㸪ὸ㒊ᵓ㐀ࡣ௚Ⅼࡼࡾ㐜࠸࡜ᛮࢃࢀࡿࠋ
⾲㠃Ἴࡢศ㞳ୖグࡢゎᯒ࡛ࡣᚓࡽࢀࡓ┦஫┦㛵㛵ᩘࢆࡑࡢࡲࡲィ⟬࡟⏝࠸ࡓࡓࡵ㸪⩌㏿ᗘ࡟ࡣᐇయἼ࡜⾲㠃Ἴࡀΰᅾࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋࡑࡇ࡛ Takagi et al.(2014)ࡢᡭἲ࡟ࡼࡗ࡚⾲㠃Ἴࡢศ㞳ࢆ⾜(a)(b)ࡗࡓࠋࣞ࢖࣮ࣜἼࡢᴃ෇㐠ື࡜ࡣᑐ↷ⓗ࡟ P Ἴࡣ┤㐍⢏Ꮚ㐠ືࢆ᭷ࡍࡿࠋTakagi et al.(2014)࡛
ࡣ Vertical-Radial ┦஫┦㛵㛵ᩘ(ZR)㸪Radial-Vertical ┦஫┦㛵㛵ᩘ(RZ)ࢆồࡵ㸪࿴ࢆ࡜ࡿࡇ࡜࡛ࣞ࢖࣮ࣜἼࡢᐤ୚ࢆ┦ẅࡋ࡚ PἼࡢᐤ୚ࡢࡳࢆಖᣢࡋ㸪ᑐ↷ⓗ࡟ ZR ࡜ RZ ࡢᕪࢆ࡜ࡿࡇ࡜࡛ PἼࡢᐤ୚ࢆ┦ẅࡋ࡚ࣞ࢖࣮ࣜἼࡢᐤ୚ࡢࡳࢆಖᣢࡍࡿࡇ࡜࡛ศ㞳ࢆ⾜࠺ࠋศ㞳ࢆ⾜ࡗࡓࣞ࢖࣮ࣜἼࡢẚ㍑ ᑐ ㇟ ࡜ ࡋ ࡚ 㸪 Nishida etal.(2008)ࡢ㏿ᗘᵓ㐀ࣔࢹࣝࢆ౑
⏝ࡋࡓࠋࣔࢹࣝࡣ Hi-net ࡢഴᩳィ࡛ᐃࡉࢀࡓᖖ᫬ᚤືࡢᆅ㟈Ἴᖸ΅ゎᯒ࠿ࡽ᪥ᮏ඲ᅜࡢ S Ἴ㏿ᗘᵓ㐀ࡀồࡵࡽࢀ࡚࠾ࡾ㸪⦋ᗘ⤒ᗘ 0.1r㛫㝸㸪῝ࡉ 60km ࡲ࡛ᒙཌ 1 ੊ࡈ࡜࡟≀ᛶ್ࡀồࡵࡽࢀ࡚࠸ࡿࠋ௒ᅇࡣほⅬ࿘㎶࡛㸪≀ᛶ್ࡀồࡵࡽࢀ࡚࠸ࡿ 4Ⅼࢆ⏝࠸࡚⥺ᙧ⿵᏶ࢆ⾜࠸㸪ほⅬ┤ୗࡢᵓ㐀࡜ࡋࡓࠋᅗ 5 ࡟ศ㞳ࢆ⾜ࡗࡓ⾲㠃Ἴࡢ⩌㏿ᗘ࡜ SN ẚ㸪Nishida ࣔࢹࣝᅗ 5 Vertical ᪉ྥࡢ 6 ࢝᭶㔜ྜ┦஫┦㛵ࡼࡾࡼࡾィ⟬ࡋࡓࣞ࢖࣮ࣜἼ⩌㏿ᗘ⟬ᐃࡋࡓศ㞳⩌㏿ᗘ࡜ SN ẚࢆ♧ࡍࠋ඲యⓗ࡟ Nishida ࣔࢹ(a)ࡣ⩌㏿ᗘ㸪(b)ࡣ SN ẚࢆ♧ࡍࣝࡼࡾ㐜࠸⤖ᯝ࡜࡞ࡗࡓࠋ

Nishida ࣔࢹࣝࡣᆅ⾲࠿ࡽ 1km ࡈ࡜ࡢᵓ㐀ࢆồࡵ࡚࠸ࡿࡢ࡛㸪ᐇ㝿ࡢὸ㒊ࡢ㏿ᗘᵓ㐀ࡼࡾ㏿ࡃ࡞ࡗ࡚࠸ࡿࡇ࡜ࡀཎᅉ࡜ࡋ࡚⪃࠼ࡽࢀࡿࠋ௒ᚋᐇ㝿ࡢὸ㒊ᵓ㐀ࡸࡑࢀ࡟‽ࡎࡿᵓ㐀ࢆࣔࢹࣝ࡟ྲྀࡾධࢀࡿࡇ࡜࡛㸪⟬ᐃ⤖ᯝ࡜ࡢ୍⮴ࡀᮃࡵࡿ࡜⪃࠼ࡽࢀࡿࠋ2-3 ࡢ⩌㏿ᗘࢆศ㞳๓࡜ẚ㍑ࡍ

183ࡿ࡜࿘Ἴᩘ࡟ࡼࡗ࡚ኚ໬ࡋ࡚

(a)(b)

࠸ࡿࡼ࠺࡟ぢ࠼ࡿࠋࡇࡢࡇ࡜
࠿ࡽศ㞳࡟ࡼࡗ࡚⾲㠃Ἴࢆ༟㉺ࡉࡏࡿࡇ࡜ࡀฟ᮶࡚࠸ࡿ࡜
ุ᩿࡛ࡁࡿࠋࡲࡓ㸪SN ẚࡢྥୖࡶ☜ㄆ࡛ࡁࡓࠋ4-5 ࡢ⩌㏿ᗘࡣ SN ẚࡀ㧗࠸ࣉࣛࢫ᪉ྥࢆぢࡿ࡜㸪ࡸࡣࡾ⣙ 1.2km/s⛬ᗘࡢ௚࡜ẚ࡭࡚㐜࠸್ࢆ♧ࡋ࡚࠸ࡿࠋ
ཧ↷Ⅼࡢ౑⏝ཧ ↷ Ⅼ ࡜ ࡋ ࡚ F-net ඵ ⁁(N.YMZF)࡜ Hi-net ࠸ࢃࡁす(N.IWWH)ࢆ౑⏝ࡋ㸪1 ࢝᭶ࡢ㔜ྜ┦஫┦㛵ࢆ⏝࠸࡚⩌㏿ᗘ㸪
SN ẚࢆ⟬ᐃࡋࡓ㸦౛࠼ࡤ㸪
Yamanaka et al., 2015㸧ࠋᅗ 6࡟࠸ࢃࡁす࡜༡໭⥺࡜ࡢ┦஫┦㛵ࡼࡾ⟬ᐃࡋࡓ⩌㏿ᗘ࡜
SN ẚࢆ♧ࡍࠋ࠸ࢃࡁすࡣ⥺ࡼࡾෆ㝣࡟఩⨨ࡋ࡚࠸ࡿࡓ
ࡵ࣐࢖ࢼࢫ᪉ྥ࡛ SN ẚࡀ㧗ࡃ࡞ࡗ࡚࠸ࡿࠋ⩌㏿ᗘࢆẚ㍑
ࡍࡿ࡜㸪ᅗ࡛ࡣ┬␎ࡋࡓ NS-3
ࢆྵࡵ㸪NS-1 ࠿ࡽ NS-4 ࡲ࡛ࡣ㏿ᗘᵓ㐀ࡀఝ࡚࠸ࡿ࡜ุ᩿
࡛ࡁࡿࠋNS-5 ࡟㛵ࡋ࡚ࡣ㸪ཧ↷Ⅼࢆ⏝࠸ࡿࡇ࡜࡛ࡼࡾࡣࡗࡁࡾ࡜ὸ㒊ࡢ㐜࠸ᵓ㐀ࢆ┦ᑐⓗ࡟☜ㄆ࡛ࡁࡓ࡜ゝ࠼ࡿࠋࡲ࡜ࡵ⚟ᓥ┴ᮾ㒊࡛༡໭᪉ྥࡢࣜࢽ࢔࢔ࣞ࢖ほ࡟ᆅ㟈Ἴᖸ΅ἲゎᯒࢆ㐺⏝ࡋ⩌㏿ᗘࢆồࡵ㸪
Nishida ࣔࢹࣝ࡜ࡢẚ㍑ࢆ⾜ࡗࡓࠋࡲࡓ㸪ཧ↷Ⅼࢆ⏝࠸࡚ྛ

ᅗ 6 ࠸ࢃࡁす(N.IWWH)࠿ࡽ༡໭

⥺࡬ࡢ⩌㏿ᗘ࡜ SN ẚ(a)ࡣ⩌㏿ᗘ㸪(b)ࡣ SN ẚࢆ♧ࡍⅬ࡛ࡢ㏿ᗘᵓ㐀ࡢẚ㍑ࢆ⾜ࡗࡓࠋNishida ࣔࢹࣝ࡜ࡢẚ㍑࡛ࡣ

184

ほ⤖ᯝࡀ඲యⓗ࡟ Nishida ࣔࢹࣝࡼࡾ㐜࠸⤖ᯝ࡜࡞ࡗࡓࠋཎᅉ࡜ࡋ࡚ Nishida ࣔࢹ࡛ࣝࡣ⾲ࡉࢀ࡚࠸࡞࠸⾲ᒙࡢᙳ㡪ࡀ⪃࠼ࡽࢀ㸪ὸ㒊ᵓ㐀࡜ࡢẚ㍑ࢆ⾜࠺࠺࠼࡛ࡣ㸪᪂ࡓ࡟⾲ᒙࡢᵓ㐀ࢆྲྀࡾධࢀࡿᚲせࡀ࠶ࡿ࡜ᛮࢃࢀࡿࠋཧ↷Ⅼࢆ⏝࠸ࡓẚ㍑࡛ࡣ NS-1 ࠿ࡽ NS-4 ࡀ㏆࠸㏿ᗘᵓ㐀ࢆᣢࡘࡇ࡜ࡀ♧၀ࡉࢀ㸪NS-5 ௜㏆ᖹ㔝㒊ࡢ㐜࠸ᵓ㐀ࢆ⾲ࡍࡇ࡜ࡀ࡛ࡁࡓ࡜ᛮࢃࢀࡿࠋࡋ࠿ࡋ㸪ཧ↷Ⅼࡣ 1 ࢝᭶ศࡢࢹ࣮ࢱ࡛ゎᯒࢆ⾜ࡗࡓࡓࡵ㸪௒ᅇࡼࡾ㐲᪉ࡢཧ↷Ⅼࢆ౑⏝ࡍࡿሙྜ࡟ࡣࡉࡽ࡟㛗ᮇ㛫ࡢࢹ࣮ࢱࡀᚲせ࡛࠶ࡿ࡜ุ᩿ࡉࢀࡿࠋㅰ㎡㸦බ㈈㸧ᆅ㟈ண▱⥲ྜ◊✲᣺⯆఍࠿ࡽࢹ࣮ࢱࢆᥦ౪ࡋ࡚࠸ࡓࡔ࠸ࡓࠋ㸦ᅜ◊㸧㜵⅏⛉Ꮫᢏ⾡◊✲ᡤ࠿ࡽ F-net㸪Hi-net ࡢࢹ࣮ࢱࢆᥦ౪ࡋ࡚࠸ࡓࡔ࠸ࡓࠋ୍㒊ࡢᅗ㠃ࡢసᡂ࡟ࡣ GMT(Wessel andSmith, 1998)ࢆ౑⏝ࡋࡓࠋグࡋ࡚ㅰពࢆ⾲ࡍࡿࠋཧ⪃ᩥ⊩

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