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ᅦܖٻޢᨥ້້֩ޛӪऴإᄂᆮ‒ ᇹ ‧ ׅᄂᆮᨼ˟↙↸↢↚‒ ᇹ ‒ׅ ᙱଐஜ້ޛѣᄂᆮᨼ˟‒ ᜒᙲଓᨼ Program & Abstracts of the 5th Meeting of AIG Collaborative Research Institute for International Study on Eruptive History and Informatics, Fukuoka University and 9th Meeting of of West Japan Volcanism Research Group ȕǣȪȔȳ ȑǤǿȳฯ 7-8th February, 2015; 18th Building, Nanakuma Campus, Fukuoka University ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ➨ ᅇ◊✲㞟࡞ࡽࡧ ➨ ᅇ す᪥ᮏⅆᒣάື◊✲㞟 ࣉࣟࢢ࣒ࣛ ᪥⛬㸸2015 ᖺ 2 ᭶ 7 ᪥㸦ᅵ㸧ࠥ8 ᪥㸦᪥㸧 ሙ㸸⚟ᒸᏛ㝰࢟ࣕࣥࣃࢫ 18 ྕ㤋 1824 ᩍᐊ 2 ᭶ 7 ᪥㸦ᅵ㸧༗ᚋ ࢭࢵࢩࣙࣥ㸯㸸ᕞࡢⅆᒣᆅ㉁Ꮫ(13:00 – 15:30) 㸦ᗙ㛗㸸ᡂᑿⱥோ࣭ዟ㔝 㸧 1-01 ዟ㔝 㸦⚟ᒸ㸧 ࠕᅵተヨᩱࡢᨺᑕᛶⅣ⣲ᖺ௦㸸ᓥ⚟Ụᓥ㸪㨣ᓅ㝆ୗࢫࢥࣜࡢ ࠖ 1-02 ⏣ᮧᬛᘺ㸦す᪥ᮏᢏ⾡㛤Ⓨ㸧 ࣭㛗㇂୰㸦⇃ᮏ㸧 ࣭Paul Wallace 㸦࢜ࣞࢦࣥ㸧࣭Ᏻ⏣ ᩔ㸦ᮾி㸧࣭᳃ ᗣ㸦࠸ࡢࡕࡢࡓࡧ༤㸧 ࠕᕞࡢⅆᒣࣇࣟࣥࢺ࠾ࡅࡿ࣐ࢢ࣐⏕ᡂࣉࣟࢭࢫ㹼࣓ࣝࢺໟ᭷ ≀ࡽࡢࣉ࣮ࣟࢳ㹼ࠖ 1-03 ⏣ᓥ㟹ஂ㸦᪥ᮏᕤႠ㸧 ࠕ㟝ᓥⅆᒣ⩌㸪⏋ᓅⅆᒣࡢⓎ㐩ྐ̿」ᡂⅆᒣࡢ㢮ᆺྥࡅ̿ࠖ 㸦ఇ ᠁㸧14:10 – 14:20 1-04 ⟄ṇ᫂㸦ࢲࣖࢥࣥࢧࣝࢱࣥࢺ㸧࣭ᑠᯘဴኵ㸦㮵ඣᓥ㸧 ࠕ㟝ᓥⅆᒣ⩌㸪ᚚ㖊ⅆᒣ࠾ࡅࡿࢢࣝࢳࢿ࣮ࢺⅆ○ὶࠖ 1-05 ᡂᑿⱥோ㸦Ṋᒸྎ㧗㸧 ࠕᖾᒇⅆ○ὶࡼࡿᆅᒙࡢᶓ㌿⌧㇟ࠖ 1-06 ᆏཱྀ ᕦ࣭ᰆཎ㞞ᶞ࣭ᒣᓮᆂ࣭ዟ㔝 㸦⚟ᒸ㸧 ࠕ⇕࣑ࣝࢿࢵࢭࣥࢫ㸦TL㸧ᖺ௦࠾ࡼࡧᒾᏛ⤌ᡂࡼࡿᯇࡢྎ ᒾᒌ࡞ࡔࢀሁ✚≀ࡢ⤥※᥎ᐃࠖ ࢭࢵࢩࣙࣥ㸰㸸㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢࡓࡵࡢሗᏛ(15:40 – 17:10) 㸦ᗙ㛗㸸㭯⏣┤அ࣭ዟᮧ 㸧 2-01 ᶓ⏣ಟ୍㑻㸦ඖ࣭ᓥ᰿㸧 ࠕ㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢసᡂࡣ࡞ࡐᅔ㞴㸽(2)ࠖ 2-02 ዟᮧ ࣭▮⩚⏣ඃ㍤࣭㧗ᶫఙᘺ࣭㭯⏣┤அ㸦⚟ᒸ㸧 ࠕ㟢㢌ሗࡢ㞟ඹ᭷ࡢࡓࡵࡢሗࢧࢺ㞟ᨭࢶ࣮ࣝࡢ ᩚഛࠖ 2-03 㧗ᶫఙᘺ࣭ዟᮧ ࣭㭯⏣┤அ㸦⚟ᒸ㸧 ࠕ◊✲ࢹ࣮ࢱඹ᭷ࡢࡓࡵࡢᆅ⌮ሗࢹ࣮ࢱ࣮࣋ࢫࢧ࣮ࣅࢫࡢᵓ ⠏ࠖ 2-04 㭯⏣┤அ࣭㧗ᶫఙᘺ࣭ዟᮧ 㸦⚟ᒸ㸧 ࠕⅆᒣᄇⅆྐሗࢹ࣮ࢱ࣮࣋ࢫࡢ ḟ⏝ࡘ࠸࡚ࠖ 2 ᭶ 8 ᪥㸦᪥㸧 ࢭࢵࢩࣙࣥ㸱㸸࢝ࣝࢹࣛⅆᒣ࢝ࣝࢹࣛᄇⅆ(9:00 – 14:00) 㸦ᗙ㛗㸸୕ᾆຓ࣭ୗྖಙኵ࣭✄ᐶோ㸧 3-01 ✄ᐶோ㸦す᪥ᮏᢏ⾡㛤Ⓨ㸧 ࣭ᡂᑿⱥோ㸦Ṋᒸྎ㧗㸧 ࣭ዟ㔝 㸦⚟ᒸ㸧࣭ᑠᯘဴኵ㸦㮵ඣᓥ㸧 ࠕ༡ᕞ㸪ụ⏣࢝ࣝࢹࣛࡢᄇⅆྐࠖ 3-02 ୗྖಙኵ㸦⏘⥲◊㸧 ࠕጸⰋධᡞⅆ○ὶᄇฟ⮳ࡿ๓㥑ᄇⅆ㐣⛬㸸࣐ࢢ࣐⁀ࡲࡾࡢῶᅽ 㐍⾜ࠖ 3-03 ୕ᾆຓ㸦㟁୰◊㸧 ࠕ㝗ἐ࢝ࣝࢹࣛࡢᄇฟ㔞࣐ࢢ࣐⁀ࡾࡢ‽ഛᮇ㛫ࠖ 㸦ఇ ᠁㸧11:00 – 11:10 3-04 ㉿ 㭉㸦ᮾ㸧 ࠕ㧗⢭ᗘᆅ㟈Ἴࢺࣔࢢࣛࣇ࣮ࡽぢࡓάⅆᒣୗࡢ῝㒊ᵓ㐀ࠖ 3-05 ᒣᓮ⚽ே࣭㛗㇂୰㸦⇃ᮏ㸧࣭Ᏻ⏣ ᩔ㸦ᮾி㸧 ࠕ㜿⸽-4ⅆ○ὶሁ✚≀ࡢᩳ㛗▼࠾ࡼࡧ࣓ࣝࢺໟ᭷≀ࡽࡳࡓ࣐ࢢ࣐ ⤌ᡂࡢ㛫ኚࠖ 㸦 㣗㸧12:10 – 13:00 3-06 ᑠᯘဴኵ㸦㮵ඣᓥ㸧࣭ᡂᑿⱥோ㸦Ṋᒸྎ㧗㸧 ࠕ㨣⏺࢝ࣝࢹࣛࡢ࢝࣍ࣖᄇⅆࠖ 3-07 ዟ㔝 㸦⚟ᒸ㸧 ࠕᱜᓥⅆᒣࡢᄇⅆྐࡽࡳࡓ⸃ᦶᄇⅆࡢྍ⬟ᛶࠖ 3-08 ⏣ཱྀᖾὒ㸦⚟ᒸ㸧 ࠕᆅ⊹ࡸ Ἠᆅᇦㄆࡵࡽࢀࡿ㧗 㓟ᛶࡢⅆᒣᛶὶయࡢྡṧࡾࠖ 3-09 Ώ㑓බ୍㑻㸦ᕞ㸧 ࠕⅆᒣάືึᮇࡢࢸࣇࣛࢆࡗࡓᒾ▼Ꮫⓗࣔࢽࢱࣜࣥࢢʊࢭࣥ ࢺ࣊ࣞࣥࢬⅆᒣ 1980 ࡢ࣮ࠖ ࢭࢵࢩࣙࣥ㸲㸸ࣥࢻࢿࢩࡢⅆᒣ(14:10 – 15:30) 㸦ᗙ㛗㸸⏣ཱྀᖾὒ㸧 4-01 ୰⏣⠇ஓ㸦ᮾி㸧 ࣭ྜྷᮏᏹ㸦ᐩኈⅆᒣ◊㸧࣭๓㔝 ῝㸦ᮾ ி㸧ཱྀ࣭ṇே㸦ி㒔㸧 ࠕࣥࢻࢿࢩ㸪ࢩࢼࣈࣥⅆᒣࢣ࣮ࣝࢺⅆᒣࡢᄇⅆࠖ 4-02 Ᏺᒇ௨ᬛ㞝㸦㔠ἑ࣭ྡᩍᤵ㸧 ࠕࣥࢻࢿࢩࡢⅆᒣᆅᙧࠖ 4-03 Agung Harijoko and Wayan Warmada ࠕVolcanic history and geothermal activity in Dieng geothermal field, central Java, Indonesiaࠖ ࢭࢵࢩࣙࣥ㸳㸸ࣇࣜࣆࣥࡢⅆᒣ(15:40 – 17:20) 㸦ᗙ㛗㸸ዟ㔝࣭㫽┿அ㸧 5-01 Chris Newhall ࠕGeology and crisis management of Pinatubo volcano, central Luzon, Philippinesࠖ 5-02 㧗ᓥ ࣭すᕝ 㸦⛅⏣㸧࣭E. Bariso࣭M.T. Quilalang࣭ A. Daag (PHIVOLCS)࣭ዟ㔝 㸦⚟ᒸ㸧࣭ᑠᯘဴኵ㸦㮵ඣᓥ㸧 ࠕࣇࣜࣆࣥࡢࣆࢼࢶ࣎ⅆᒣᒣ㡬࢝ࣝࢹࣛ†࿘㎶ࡢ⇕࣑ࣝࢿࢵࢭ ࣥࢫ㸦TL㸧ᖺ௦ࠖ 5-03 ዟ㔝 㸦⚟ᒸ㸧 ࣭୰ᮧಇኵ㸦ྡྂᒇ㸧࣭E. Bariso࣭M.T. Quilalang࣭A. Daag (PHIVOLCS)࣭ᑠᯘဴኵ㸦㮵ඣᓥ㸧 ࠕRadiocarbon dating of wood trunks from crater wall of Pinatubo volcano, Luzon Island, Philippinesࠖ 5-04 㫽┿அ㸦⇃ᮏ㸧 ࣭E. Bariso࣭D.J. Rivera࣭R. Lim࣭C. Pogay࣭ A. Daag㸦PHIVOLCS㸧࣭ᒣᓮᆂ࣭୰す࣭ዟ㔝 㸦⚟ᒸ㸧 ࠕࣃࢱࣥ†ࡢ࣮࣎ࣜࣥࢢ᥀๐㸦㏿ሗ㸧ࠖ Program of 5th Meeting of AIG Collaborative Research Institute for International Study on Eruptive History and Informatics, Fukuoka University and 9th Meeting of West Japan Volcanism Research Group Date㸸7-8th February, 2015 Venue 㸸 Room 1824 in 18th Building, Nanakuma Campus, Fukuoka University Day 1 (7th February, 2015) Session 1: Volcanic Geology in Kyushu Island (13:00 – 15:30) 1-01 M. Okuno: Radiocarbon dating of paleosol: case study on Onidake scoria falls, Fukue Island 1-02 T. Tamura et al.: Magma generation process beneath volcanic front of Kyushu arc, Japan - Approach from melt inclusion – 1-03 Y. Tajima: Eruptive history of Koshikidake volcano in the Kirishima volcanic group - A study of the type for compound or composite volcanoes(Break) 14:10 – 14:20 1-04 M. Tsutsui and T. Kobayashi: Agglutinate and pyroclastic flow deposit at the Ohachi volcano, Kirishima volcanic group, southern Kyushu, Japan 1-05 H. Naruo: Overturned strata caused by Koya ignimbrite from Kikai caldera 1-06 T. Sakaguchi et al.: Source of Matsunodai debris avalanche deposit inferred from thermoluminesence age and chemical composition, Kuju volcanic group, central Kyushu, Japan Session 2: Informatics for Outcrop Database (15:40 – 17:10) 2-01 S. Yokota: Difficulties in construction of geological exposures database (2) 2-02 M. Okumura et al.: Preparation of outcrop information site and supporting tools for collecting and sharing geological data 2-03 S. Takahashi et al.: Development of Geo-Information Database Service for Data Sharing 2-04 N. Tsuruta: About secondary use of eruptive history and informatics database Day 2 (8th February, 2015) Session 3: Caldera Volcanoes and Caldera-forming Eruptions (9:00 – 14:00) 3-01 H. Inakura et al.: Eruptive history of Ikeda caldera, southern Kyushu, Japan 3-02 N. Geshi: Precursory eruptive process for the Ito ignimbrite eruption of Aira caldera: Decompression process of the magma chamber 3-03 D. Miura: The volume and periodicity of magma discharge at the caldera-forming eruption: A review (Break) 11:00 – 11:10 3-04 D. Zhao: Tomographic imaging of the deep structure of active volcanoes 3-05 H. Yamasaki et al.: Temporal variation of magma composition as observed by plagioclase and melt inclusions in Aso-4 pyroclastic flow deposit (Lunch) 12:10 – 13:00 3-06 T. Kobayashi and H. Naruo: Akahoya eruption of Kikai caldera 3-07 M. Okuno: Possibility of biggest eruption of Sakurajima volcano, viewed from eruptive history 3-08 S. Taguchi: Remnant of volcanic fluid in geothermal manifestations such as steaming ground and hot springs --- a good monitoring point for big eruptions? --- 3-09 K. Watanabe: Petrological monitoring using early tephra for volcanic activity - Case study of Mt. St. Helense 1980 eruption-S. Session 4: Volcanology in Indonesia (14:10 – 15:30) 4-01 S. Nakada et al.: Eruptions at Sinabung and Kelud in Indonesia 4-02 I. Moriya: Volcanic geomorphology of Indonesia 4-03 A. Harijoko and I W. Warmada: Volcanic history and geothermal activity in Dieng geothermal field, central Java, Indonesia Session 5: Volcanology in Philippines (15:40 – 17:20) 5-01 C. Newhall: Geology and crisis management of Pinatubo volcano, central Luzon, Philippines 5-02 I. Takashima et al.: Thermoluminescence (TL) age of rocks from summit crater lake at Pinatubo volcano, Luzon Island, Philippines 5-03 M. Okuno et al.: Radiocarbon dating of wood trunks from crater wall of Pinatubo volcano, Luzon Island, Philippines 5-04 M. Torii et al.: Boring cored sediments from Paitan Lake, central Luzon, Philippines ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 1-01 ᅵተヨᩱࡢᨺᑕᛶⅣ⣲ᖺ௦㸸ᓥ⚟Ụᓥ㸪㨣ᓅ㝆ୗࢫࢥࣜࡢ ዟ㔝 㸦⚟ᒸ࣭⌮㸧 Radiocarbon dating of paleosol: case study on Onidake scoria falls, Fukue Island M. Okuno (Fac. Sci., Fukuoka Univ.) ࠾ࡔࡅ すᕞ㸪ᓥิᓥࡢ⚟Ụᓥ༡ᮾ㒊⨨ࡍࡿ㨣ᓅ ⅆᒣ⩌ࡣ㸪ᶆ㧗 315m ࡢ㨣ᓅⅆᒣ㸦Fig. 1㸸 ᯇ㸪1977㸧ࢆ୰ᚰ 11 ࡢ༢ᡂⅆᒣࡽ࡞ࡿ㸦㛗ᒸ࣭ྂᒣ㸪2004㸧 㸬㨣ᓅⅆᒣࡣ㸪㨣ᓅ㝆 ୗࢫࢥࣜሁ✚≀┤ୗࡢᅵተࡽ 18,090±100 BP㸦GX-25301-AMS㸧ࡢ 14C ᖺ௦ࡀᚓࡽࢀ࡚࠸ ࡿ㸦㛗ᒸ࣭ྂᒣ㸪2004㸧 㸬ࡲࡓ㸪ᗈᇦࢸࣇࣛࡢᒙ㛵ಀࡣ㸪ጸⰋ Tn 㝆ୗⅆᒣ⅊㸦AT㸸⏫⏣࣭ ᪂㸪1976㸧㨣⏺࢝࣍ࣖ㝆ୗⅆᒣ⅊㸦K-Ah㸸⏫⏣࣭᪂㸪1978㸧ࡢ㛫࠶ࡿ㸦㛗ᒸ࣭ྂ ᒣ㸪2004㸧 㸬AT K-Ah ࡢᖺ௦ࡣ 29 cal kBP ࠾ࡼࡧ 7.3 cal kBP ࡛㸦ዟ㔝㸪2002㸧 㸪ୖグࡢ 14C ᖺ௦ࡣᴫࡡጇᙜ࡛࠶ࡿ㸬ᅇ㸪㨣ᓅ㝆ୗࢫࢥࣜሁ✚≀ࡢᖺ௦ࢆ᳨ウࡍࡿࡓࡵ㸪ࡑࡢ┤ୗ ࡢᅵተヨᩱࡢ 14C ᖺ௦ࢆຍ㏿ჾ㉁㔞ศᯒ㸦AMS㸧ἲࡼࡾ ᐃࡋࡓ㸬᥇ྲྀヨᩱࡢ⏘≧ࢆ Fig. 2 ࡦࡢࡔࡅ ࡋ࠾ࡘ ♧ࡍ㸬ࡇࡇ࡛ࡣ㸪㨣ᓅ㝆ୗࢫࢥࣜሁ✚≀ࡀᅵተᒙࢆࡋ࡚㸪ⅆࣀᓅⅆᒣࡢሷὠ⁐ᒾࢆそ ࠺㸬ᅵተᒙࡢᒙཌࡣ⣙ 20 cm ࡛㸪㨣ᓅ㝆ୗࢫࢥࣜሁ✚≀┤ୗࡢཌࡉ⣙ 2 cm ࢆሢ≧࡛᥇ྲྀࡋ ࡓ㸬 ᐃ⤖ᯝࢆ Table 1 ♧ࡍ㸬ᚓࡽࢀࡓ 14C ᖺ௦್ࡣ㸪19,840±120 BP㸦į13C=í19.0‰㸪JAT7769㸧࡛࠶ࡿ㸬Table 1 ࡢ㸰ࡘࡢᖺ௦್ࡣ㸪ㄗᕪ⠊ᅖࢆ㉸࠼୍࡚⮴ࡋ࡚࠸࡞࠸ࡀ㸪ᒙࡽࡣ ࡕࡽࡶ࠸࠼࡞࠸㸬ୗࡢሷὠ⁐ᒾࡢ K-Ar ᖺ௦ࡶ㸪0.05±0.03 Ma ࡛㸦㛗ᒸ࣭ྂᒣ㸪2004㸧 㸪 ᗈᇦࢸࣇࣛࡢ㛵ಀࡶྵࡵ࡚ᒙⓗࡣ▩┪ࡋ࡞࠸㸬๓ฎ⌮ࡋࡓヨᩱࡢඖ⣲ศᯒ⤖ᯝࡣ㸪 C=0.43%㸪N=0.05%㸪C/N=9.14 ࡛࠶ࡿ㸬ࡇࡢ C/N ࡣ㸪ᅵተヨᩱࡋ࡚ศゎࡀ࠶ࡿ⛬ᗘ㐍ࢇ࡛ ࠸ࡿࡇࢆ♧၀ࡋ㸪ᖺ௦್ࡀⱝ㏉ࡗ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿ㸦Okuno et al., 1997㸹ዟ㔝㸪2001㸧 㸬 -1- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡋࡋ㸪ࡇࡢᖺ௦್ࡣ㸪ࡶ࠺୍᪉ࡢ 18,090±100 BP㸦Table 1㸧ࡼࡾ 2000 14C yr ྂࡃ㸪ⱝ㏉ ࡾࡢྍ⬟ᛶࡣప࠸⪃࠼ࡽࢀࡿ㸬㝆ୗࢸࣇࣛ┤ୗࡢᅵተヨᩱࡣ㸪⌧ᆅᛶࡢ᭷ᶵ≀࡞ࡢ࡛㸪ࡑ ࡢ 14C ᖺ௦ࡣᄇฟᖺ௦ࢆ♧ࡍ⪃࠼ࡽࢀࡿ㸦Okuno et al., 1997㸹Okuno and Nakamura, 2003㸧 㸬 ㍑ṇᬺᖺ㸦2ı㸧ࡣ㸪23,550 – 24,194 cal BP㸦probability=100%㸧࡛㸪⣙ 24 cal kBP ࡢᬺᖺ௦┦ ᙜࡍࡿ㸬14C ᖺ௦ ᐃ࡛ࡣ㸪ἾⅣࡸⅣᮌ∦ࢆぢ࠸ࡔࡍ㸪ࡉࡽᅵተヨᩱࢆ ᐃࡍࡿࡇࡶ ⪃࠼ࡽࢀࡿ㸬ࡑࡢ㝿ࡣ㸪C/N ࡀ 20 ㏆࠸ᅵተ᭷ᶵ≀ࡢศゎࡢࡼࡾ㐍ࢇ࡛࠸࡞࠸ヨᩱࡀᚲせ ࡛࠶ࡿ㸬 Fig. 1 Isopach map of the Onidake Scoria Falls (after, Nagaoka and Furuyama, 2004). A star indicates sampling site. -2- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 Fig. 2 Photographs showing occurrence of dated sample. Arrow in (B) indicates sampling horizon. Table 1 Results of AMS radiocarbon dating of paleosol samples below the Onidake Scoria Falls. -3- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 1-02 ᕞࡢⅆᒣࣇࣟࣥࢺ࠾ࡅࡿ࣐ࢢ࣐⏕ᡂࣉࣟࢭࢫ 㹼࣓ࣝࢺໟ᭷≀ࡽࡢࣉ࣮ࣟࢳ㹼 ⏣ᮧᬛᘺ㸦す᪥ᮏᢏ⾡㛤Ⓨ㸧࣭㛗㇂୰㸦⇃ᮏ㸧 Paul Wallace㸦࢜ࣞࢦࣥ㸧࣭Ᏻ⏣ ᩔ㸦ᮾி㸧࣭᳃ ᗣ㸦࠸ࡢࡕࡢࡓࡧ༤㸧 Magma generation process beneath volcanic front of Kyushu arc, Japan - Approach from melt inclusion T. Tamura (West JEC), T. Hasenaka (Kumamoto Univ.), P. Wallace (Oregon Univ.), A. Yasuda (Tokyo Univ.), Y. Mori (Kitakyushu Museum of Natural History & Human History) ᕞࡢⅆᒣࣇࣟࣥࢺ⨨ࡍࡿ 4 ࡘࡢ➨ᅄ⣖ⅆᒣ࡛࠶ࡿ㜿⸽㸦୰ᓅ࣭ ⏕ᓅ㸧 㸪㔜㸦ᖹ ᓅ㸧㸪㟝ᓥ㸦ᚚ㖊㸧㸪㛤⪺ᓅࡘ࠸࡚㸪ࡑࢀࡽࡢⅆᒣᄇฟ≀୰ྵࡲࢀࡿ࢝ࣥࣛࣥ▼ᩬᬗ୰ࡢ ࣓ࣝࢺໟ᭷≀ࡢᏛ⤌ᡂࡽ㸪ึ⏕࣐ࢢ࣐ཬࡧࢫࣛࣈὶయࡢ⤌ᡂࡢ᥎ᐃࢆヨࡳࡓ㸬࢝ࣥࣛࣥ ▼ࡣ࣐ࢢ࣐ࡢ⤖ᬗศࡢ᪩ᮇᬗฟࡍࡿ㖔≀࡛࠶ࡾ㸪ࡑࡢ୰ᤕ⋓ࡉࢀࡓ࣓ࣝࢺໟ᭷≀ࡣࡼ ࡾᮍศ࡞ࡢ࣐ࢢ࣐ࡢ⤌ᡂࢆಖᣢࡍࡿࡇࡀᮇᚅ࡛ࡁࡿ㸬᥎ᐃࡋࡓึ⏕࣐ࢢ࣐ཬࡧࢫࣛࣈ ὶయࡢ⤌ᡂࡽ㸪ᕞࡢⅆᒣࣇࣟࣥࢺ࠾ࡅࡿ࣐ࢢ࣐⏕ᡂࣉࣟࢭࢫࡘ࠸᳨࡚ウࡋࡓ㸬 ᥎ᐃࡋࡓึ⏕࣐ࢢ࣐ࡢ⤌ᡂཬࡧࢫࣛࣈὶయࡢ⤌ᡂࡽ㸪㧗࠸ K2O 㔞ࡢ㜿⸽࣭㔜㸪ప࠸ K2O 㔞ࡢ㟝ᓥ࣭㛤⪺ࡢ 2 ࡘࡢࢢ࣮ࣝࣉศࡅࡿࡇࡀ࡛ࡁࡓ㸬ࡲࡓ㸪ࡑࢀࡒࢀࡢࢢ࣮ࣝࣉ࠾࠸ ࡚ⅆᒣ┤ୗỿࡳ㎸ࡴᾏὒࣉ࣮ࣞࢺࡢ῝ᗘࡀ␗࡞ࡗ࡚࠾ࡾ㸦Shiono, 1974; Nakada and Kamata, 1991; Wang and Zhao, 2006㸧㸪㜿⸽࣭㔜ࡢ┤ୗ࡛ࡣ⣙ 140 km ࡢ῝ᗘ࡛࠶ࡿࡢᑐࡋ㸪㟝ᓥ࣭ 㛤⪺ࡢ┤ୗ࡛ࡣ⣙ 100 km ࡛࠶ࡿ㸬ᆅୗ 110 km ௨῝࠾࠸࡚㸪ỿࡳ㎸ࡴᾏὒࣉ࣮ࣞࢺࡽࣇ ࢙ࣥࢪࣕࢺࡀ⬺Ỉศゎࡋ K2O ࡀᨺฟࡉࢀࡿࡇࡀᣦࡉࢀ࡚࠸ࡿ㸦Schmidt, 1996㸧 㸬ࡲࡓ㸪 㜿⸽࣭㔜㟝ᓥ࣭㛤⪺ࡢᒾࡢ Ba 㔞㸦Ba ࡣࣇ࢙ࣥࢪࣕࢺࡢࢺ࣮ࣞࢧ࣮㸹Zack et al., 2001㸧 -4- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࢆẚ㍑ࡍࡿ㸪㜿⸽࣭㔜ࡣ㟝ᓥ࣭㛤⪺ࡼࡾࡶ㧗࠸ྵ᭷㔞ࢆ♧ࡍ㸬 ௨ୖࡢࡇࡽ㸪㜿⸽࣭㔜ᆅᇦ࡛ࡣ㸪ỿࡳ㎸ࡴࣉ࣮ࣞࢺࡀ 140 km ࡢ῝ᗘ㐩ࡋ㸪ࣉ࣮ࣞ ࢺෆࡢࣇ࢙ࣥࢪࣕࢺࡀ⬺Ỉศゎࡍࡿࡇࡼࡗ࡚ K ࡀᨺฟࡉࢀ㸪ࡇࢀࡀึ⏕࣐ࢢ࣐ຍ ࡍࡿࡇ࡛⤖ᯝⓗ K2O ᐩࡴ࣐ࢢ࣐ࡀ⏕ᡂࡉࢀࡓ㸬୍᪉㟝ᓥ࣭㛤⪺ᆅᇦ࡛ࡣ㸪ỿࡳ㎸ࡴࣉ ࣮ࣞࢺࡢ῝ᗘࡀ⣙ 100 km ࡛࠶ࡾ㸪ゅ㛝▼࡞ࡢ K ஈࡋ࠸㖔≀ࡢ⬺Ỉศゎࡀ⏕ࡌ㸪⤖ᯝⓗ K2O ஈࡋ࠸࣐ࢢ࣐ࡀ⏕ᡂࡉࢀࡓ㸬ࡼࡗ࡚㸪ᕞᆅᇦ࡛ࡣⅆᒣ┤ୗỿࡳ㎸ࡴᾏὒࣉ࣮ࣞ ࢺࡢ῝ࡉ㸪ཬࡧࣉ࣮ࣞࢺࡽ⬺ỈศゎࡍࡿྵỈ㖔≀ࡢ✀㢮ࡀ࣐ࢢ࣐ࡢ⤌ᡂࢆᨭ㓄ࡋ࡚࠸ࡿ ⪃࠼ࡽࢀࡿ㸬 4 3 2 1 0 50 54 58 62 66 K2O (wt.%) in melt inclusion K2O (wt.%) in whole rock 4 3 2 1 0 50 SiO2 (wt.%) in whole rock 54 56 58 60 SiO2 (wt.%) in melt inclusion 600 5 H2O (wt.%) in melt inclusion Ba (ppm) in whole rock 52 500 400 300 200 100 0 50 54 58 62 66 SiO2 (wt.%) in whole rock Fig. 1. 4 3 2 1 0 50 52 54 56 58 SiO2 (wt.%) in melt inclusion 1-03 㟝ᓥⅆᒣ⩌㸪⏋ᓅⅆᒣࡢⓎ 㐩ྐ㸫」ᡂⅆᒣࡢ㢮ᆺྥࡅ㸫 Major and trace element compositions in whole rocks (left side). Major element and volatile compositions in olivine-hosted melt inclusions (right side). Each of five legends indicates that ۍis Nakadake from Aso volcano, یis Ojodake from Aso volcano, ڧis Hiijidake from ⏣ᓥ 㟹ஂ㸦᪥ᮏᕤႠ㸦ᰴ㸧㸧 Kuju volcano, ڹis Ohachi from Kirishima volcano and ۑis Kaimondake volcano, respectively. Eruptive history of Koshikidake volcano in the Kirishima volcanic group -5- 60 ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 - A study of the type for compound or composite volcanoesY. Tajima (Nippon Koei Co., Ltd.) 㟝ᓥⅆᒣ⩌ࡣ㸪ከᵝ࡞ᙧែࡢⅆᒣࡽᵓᡂࡉࢀࡿⅆᒣ⩌࡛࠶ࡾ㸪ⅆᒣయࡢศ㢮ࢆ⾜࠺ࡢ Ⰻዲ࡞ࣇ࣮ࣝࢻ࡞ࡿ㸬ᒣ㡬ࢆ୰ᚰ〈㔝ࡀᗈࡀࡿᡂᒙⅆᒣఝࡓᙧែࡢ㧗༓✑ᓠ㸪ᚚ㖊 ࡣ㸪ࣀୖ㸦1988㸧 㸪⟄࣭㸦2007㸧ࡼࡗ࡚ᛴ⃭ᡂ㛗ࡋࡓⓎ㐩㐣⛬ࡀ᫂ࡽࡉࢀ࡚ ࠸ࡿ㸬ࡇࡢᵝ࡞᥎⛣ࡘ࠸࡚㸪㟝ᓥⅆᒣ⩌ࡢࡢఝࡓⅆᒣ࠾࠸࡚ࡶ㉳ࡁ࡚࠸ࡿࡢ᳨ウࢆ ࡍࡿᚲせࡀ࠶ࡿ㸬㟝ᓥⅆᒣ⩌࡛ࡣ㸪㣤┒ᒣ㸪⏋ᓅ㸪ᒸᒣࡀࡇࢀࡽ㏆࠸ᡂᒙⅆᒣࡢ≉ᚩࢆ ᭷ࡋ࡚࠾ࡾ㸪㧗༓✑ᓠ㸪ᚚ㖊ࡢẚ㍑᳨ドࡀྍ⬟⪃࠼ࡽࢀࡿ㸬ࡇࡢ୰࡛ࡶ⏋ᓅⅆᒣࡣࢸࣇ ࣛ⁐ᒾࡢ㛵ಀࢆ᫂ࡽࡍࡿࡇࡀ࡛ࡁࡓࡓࡵ㸪ࡑࡢⓎ㐩㐣⛬ࡘ࠸࡚♧ࡋⅆᒣయᙧᡂࡢ ẚ㍑㆟ㄽࢆ⾜࠺㸬 㟝ᓥⅆᒣ⩌ࢆ㉳※ࡍࡿࢸࣇࣛᒙࡢ୰࡛㸪㡑ᅜᓅ㸫ᑠᯘࢸࣇࣛ㸦Kr-Kb㸧ධᡞⅆ○ὶሁ ✚≀ࡢ㛫㸪㝆ୗࢫࢥࣜᒙࡀ࠶ࡿࡇࡀ▱ࡽࢀ࡚࠸ࡿ㸬ࡇࡢ㝆ୗࢫࢥࣜᒙࡣ㸪㣤┒ᒣ ྥ࠸ᒙཌࢆቑࡍࡇࡼࡾ㸪㣤┒ᒣࢫࢥࣜᒙࡤࢀ࡚࠸ࡓ㸦㐲⸨࣭ᑠᯘ࣮࣒ࣟ◊✲ࢢࣝ ࣮ࣉ, 1969㸧 㸬୍᪉㸪Imura㸦1992㸧ࡣ㸪ྠᒙࡢ➼ᒙཌ⥺ᅗࡼࡾ㡑ᅜᓅࡀ⤥※࡛࠶ࡿ᥎ᐃ ࡋ㸪㡑ᅜᓅࢫࢥࣜᨵ⛠ࡋࡓ㸬⏣ᓥ࣭ᑠᯘ㸦2011㸧ࡣ㸪ྠᒙࡢ➼ᒙཌ⥺㸪⢏ᚄࡀ⏋ᓅ㸦௨ ୗ㸪⏋ᓅⅆᒣ㸧ྥ࠸ቑຍࡍࡿࡇࢆ♧ࡋ㸪⏋ᓅࢸࣇࣛᐃ⩏ࡋࡓ㸬ḟ㸪⏋ᓅⅆᒣࢆ ㉳※ࡍࡿ⁐ᒾࡣ㸪㟝ᓥⅆᒣ⩌ࡢᇦᗈࡃศᕸࡋ࡚࠾ࡾ㸦ᅗ 1: ἑᮧ࣭ᯇ, 1957; ᮧ࣭ ᑠᯘ, 2001㸧 㸪ⅆཱྀࡽࡢ฿㐩㊥㞳ࡣ 7 km ࢆ㉸࠼ࡿ㸬⏋ᓅ⁐ᒾࡢ⾲㠃✚ࡣ⣙ 30 km2 ࡞ࡾ㸪 Ᏻᒣᒾ⁐ᒾࡋ࡚ࡣつᶍࡢࡁ࡞ࡶࡢ࡛࠶ࡿ㸬2011 ᖺ 11 ᭶ࡽጞࡲࡗࡓすஅᓥ࠾࠸࡚ 㔞ࡢ⁐ᒾᄇฟࡀ⥅⥆ࡋ࡚࠸ࡿ⌧ᅾ㸪つᶍ࡞⁐ᒾᄇฟࡋ࡚ࡶࡑࡢᄇⅆ᥎⛣ࢆ♧ࡍᚲせࡀ ࠶ࡿ㸬 ⏋ᓅⅆᒣࡢάືࡣ㸪ึᮇᑠ㹼୰つᶍࡢࣈࣝ࢝ࣀᘧᄇⅆࡢάືࡽጞࡲࡗࡓ㸬Ks-1㹼Ks-5 ࡣᑠ㹼୰つᶍࡢᄇⅆάືࢆ⾜ࡗ࡚࠸ࡓࡀ㸪Ks-6 ࡢᛴ㔞ࡢ⁐ᒾ㝆ୗⅆ○≀ࢆᄇฟࡍ ࡿᄇⅆάືኚࡋࡓ㸬Ks-1㹼Ks-6 ࡛ࡣᄇⅆẖ▷࠸㟼✜ᮇࡀ࠶ࡗࡓ⪃࠼ࡽࢀࡿࡀ㸪Ks-1 㹼Ks-6 㛫ࡢᅵተⓎ㐩ࡣ㈋ᙅ࡛࠶ࡾ㟼✜ᮇ㛫ࡣ㛗ࡃ࡞ࡗࡓ᥎ᐃࡉࢀࡿ㸬ᇛࣨᓮ࡛ࡣ Ks-7a 㹼Ks-8 㛫ἾⅣᒙ㸪†ᡂᒙࡀㄆࡵࡽࢀࡿࡇࡼࡾ㸪ᩘⓒᖺ௨ୖࡢ㟼✜ᮇࡀ࠶ࡗࡓ⪃࠼ࡽࢀ ࡿ㸬ࡑࡢᚋ㸪Ks-8㹼Ks-9 ࡣẚ㍑ⓗ▷㛫ࡢάືࢆ⾜࠸㸪Ks-10 ࡢࣈࣝ࢝ࣀᘧᄇⅆ࡛ᡂ㛗ࢆṆ ࡵࡓ㸬ᚚ㖊ⅆᒣ࡛ࡣ㸪⣙ 1300 ᖺ๓ࡽάືࢆ㛤ጞࡋ㸪500 ᖺᚋᒣయࢆᡂ㛗ࡉࡏࡓ㧗ཎࢫ ࢥࣜᄇⅆࢆⓎ⏕ࡉࡏࡓ㸦⟄࣭㸪2007㸧 㸬㧗༓✑ᓠ」ྜⅆᒣࡶ㸪ྂ㧗༓✑㸫ⵦ∹⏣ࢸࣇ ࣛࡢᄇฟࡽ 1000 ᖺෆࡓࡿάືࡀ⏕ࡌ㸪㧗༓✑ᓠ㸫⋤Ꮚࢸࣇ࡛ࣛࡰࡑࡢάືࢆ⤊࠼ ࡓ⪃࠼ࡽࢀ࡚࠸ࡿ㸦ࣀୖ, 1988㸧㸬᭱ึᮇࡢᑠ㹼୰つᶍࡢάືࡽ㸪๓ᮇࡢᛴ⃭ᒣయࢆ -6- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ᡂ㛗ࡉࡏࡿάື⮳ࡗࡓ㸬ึᮇࡢ┦ᑐⓗ࡞ᑠつᶍ࡞άືࢆ⤒࡚㸪ᛴ⃭ᡂ㛗ࡍࡿⅆᒣయࡢⓎ 㐩㐣⛬ࡣ㸪ࡇࢀࡽࡢⅆᒣඹ㏻ࡋࡓ≉ᚩゝ࠼㸪ᡂᒙⅆᒣࡢᡂ㛗ࡣᛴ⃭ᄇฟ⋡ࡀୖࡀࡿ ᮇࡀ࠶ࡿ⪃࠼ࡽࢀࡿ㸬 ᅗ㸯 ⏋ᓅⅆᒣ࿘㎶ࡢⅆᒣᄇฟ≀. E3㹼E5㸦ືụ⁐ᒾ㸧㸪E7㹼E9㸦⏋ᓅ⁐ᒾ㸧ࡣ⏣ᓥ࣭(2014) ࡢᒾᏛศᯒᆅⅬ㸬侀ࡢ Ks- ࡣ⏋ᓅ⁐ᒾ┤ୖࡢ⏋ᓅࢸࣇࣛ. ⏋ᓅ⁐ᒾୖࡢ◚⥺ࡣ㸪࿘ᅖࡼ ࡾ᪂ࡋ࠸⁐ᒾᆅᙧ. -7- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 1-04 㟝ᓥⅆᒣ⩌㸪ᚚ㖊ⅆᒣ࠾ࡅࡿࢢࣝࢳࢿ࣮ࢺⅆ○ὶ ⟄ṇ᫂㸦ࢲࣖࢥࣥࢧࣝࢱࣥࢺ ◁㜵࣭㜵⅏ᴗ㒊㸧࣭ ᑠᯘဴኵ㸦㮵ඣᓥᏛᏛ㝔 ⌮ᕤᏛ◊✲⛉㸧 Agglutinate and pyroclastic flow deposit at the Ohachi Volcano, Kirishima Volcanic Group, Southern Kyushu, Japan M. Tsutui (DIA Consultant Co., Ltd.) and T. Kobayasho (Kagoshima Univ.) 1㸬ࡣࡌࡵ ᚚ㖊ⅆᒣ㸦ᶆ㧗 1425 m㸧ࡣ㸪㟝ᓥⅆᒣ⩌ࡢ༡ᮾ㒊⨨ࡍࡿᑠᆺࡢᡂᒙⅆᒣ࡛࠶ࡿ㸬ᚚ㖊 ࠾ࡅࡿ᭱つᶍࡢᄇⅆ࡛ࡣ㸪ⅆཱྀ㏆ഐࢢࣝࢳࢿ࣮ࢺࡀᙧᡂࡉࢀࡿࡶ㸪ᒣ⭡ࡸᒣ 㯄ⅆ○ὶࡀὶୗࡋ࡚࠸ࡿ㸬ᮏሗ࿌࡛ࡣ㸪ࡇࢀࡽࡢ㛵ಀࢆ᫂ࡽࡍࡿࡓࡵ㸪ᒣయࢆᵓᡂࡍ ࡿࢸࣇࣛࡸᒣ㯄ࡢⅆ○ὶࡢ⢏ᗘศᯒࢆᐇࡋ㸪ศᕸࡸ⏘≧࠶ࢃࡏ࡚ࡑࡢ㛵㐃ᛶࡘ࠸࡚⪃ ᐹࡋࡓ⤖ᯝࢆሗ࿌ࡍࡿ㸬 2㸬ࢢࣝࢳࢿ࣮ࢺⅆ○ὶࡢศᕸ⏘≧ ᚚ㖊ⅆᒣ࡛᭱つᶍࡢ㧗ཎࢸࣇࣛ㸦ThT㸧ࡣ㸪ᒣ㯄࠾࠸࡚ 3 ࡘࡢ㝆ୗࣘࢽࢵࢺ㸦ThT-a㸪 ThT-b ཬࡧ ThT-c㸧༊ศࡉࢀ㸪࠸ࡎࢀࡶ 106 㹼107 m3 㸦DRE㸧࣮࢜ࢲ࣮ࡢつᶍࢆ᭷ࡍࡿ㸬ࡑ ࢀࡒࢀࡢᄇⅆ࡛ⅆཱྀ㏆ഐࢢࣝࢳࢿ࣮ࢺࡀᙧᡂࡉࢀࡓ㸦┿ 1-6㸧 㸬㟢ฟࡢⰋ࠸༡ഃᒣయᩳ 㠃࡛ࡣࢢࣝࢳࢿ࣮ࢺࡀỈᖹ᪉ྥ࠶ࡿ⛬ᗘ㐃⥆ⓗほᐹྍ⬟࡛㸪ࢢࣝࢳࢿ࣮ࢺࡢᙅ⁐⤖ 㒊࡛ᑠつᶍ࡞࣮ࣟࣈࡀ⣼✚ࡋࡓᵓ㐀ࡀㄆࡵࡽࢀࡿ㸬ࡲࡓ㸪ࢢࣝࢳࢿ࣮ࢺࡀพᆅᙧཌࡃሁ ✚ࡋ࡚࠸ࡿ⟠ᡤࡸ㸪ࡼࡾୗὶഃ࡛ⅆ○ὶ㐃⥆ⓗ⛣ࡋ࡚࠸ࡿࡼ࠺ࡳ࠼ࡿ⟠ᡤࡀᏑᅾ ࡍࡿ㸬 ୍᪉ ThT-c ࡢᄇⅆ࡛ࡣ㸪ⅆ○ὶࡀ༡ഃᒣ⭡す㹼ഃᒣ㯄ศࢀ࡚ሁ✚ࡋࡓ㸦┿ 7㸧 㸬 ༡ഃᒣ⭡ࡢⅆ○ὶࡣᒣయᩳ㠃ࡢ≉ᐃࡢ࣮࢞ࣜࢆ㑅ᢥⓗὶୗࡋࡓࡢᑐࡋ㸪す㹼ഃᒣ㯄ࡢ ⅆ○ὶࡣ㞄᥋ࡍࡿⅆᒣࡢ㛫ࡢἑࢆᇙࡵ࡚ẚ㍑ⓗᗈ࠸⠊ᅖᗈࡀࡗࡓ㸬ࡲࡓ㸪ᚚ㖊ⅆᒣࡢ すᑐ㠃ࡍࡿ୰ᓅࡢᒣయᩳ㠃ࡣ㸪ࡇࡢⅆ○ὶࡀ㏻㐣ࡋࡓ㝿ṧࡋ࡚࠸ࡗࡓሁ✚≀ࡀศᕸ ࡍࡿ㸦┿ 8㸧㸬 3㸬⢏ᗘ⤌ᡂ 㝆ୗࢸࣇࣛ㸪ᒣయ㒊㸦ᶆ㧗 1100㹼1050 m ௨ୖࡢᒣయᩳ㠃ࢆᵓᡂࡋ㸪୍ぢࡋ࡚㝆ୗࢸࣇࣛࡸ -8- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ⅆ○ὶ༊ู࡛ࡁ࡞࠸୰㛫ⓗ࡞⏘≧ࡢሁ✚≀㸧ཬࡧⅆ○ὶࡘ࠸࡚㸪せ࡞㟢㢌࡛ヨᩱࢆ᥇ ྲྀࡋ㸪ࡩࡿ࠸ศࡅヨ㦂ࢆᐇࡋࡓ㸬⢏ᚄࡣ-3 ࡽ㸺5ij ࡲ࡛ 1ij 㛫㝸࡛ 9 ༊ศࡋࡓ㸬 㝆ୗࢸࣇࣛᒣయ㒊ࡣ㸪ࡍ࡚ Walker㸦1971㸧ࡢ♧ࡋࡓࠕFallࠖࡢ㡿ᇦࣉࣟࢵࢺࡉࢀࡿ㸬 ᒣయ㒊ࡣ㸪㝆ୗࢸࣇࣛࡀࣉࣟࢵࢺࡉࢀࡿ㡿ᇦ୍㒊㔜࡞ࡿࡀ㸪యⓗศ⣭ࡀᝏࡃ⢏ᚄࡀ⢒ ࠸㸬ࡲࡓ㸪ᒣయ㒊ࡢ㔝እࡢ⏘≧ࡣⅆཱྀ㏆ഐࡽᒣ㯄ྥࡗ࡚ศ⣭ࡀⰋࡃ⣽⢏࡞ࡾ㸪ከᑡ ㌿ືࡋࡓࡶࡢࢆྵࡴࡀ㸪ᒣయ㒊ࡣᇶᮏⓗ㝆ୗࢸࣇุ᩿ࣛࡋ࡚Ⰻ࠸ࡔࢁ࠺㸬 ⅆ○ὶࡣ㸪ศᕸᇦࡼࡾ␗࡞ࡿ≉ᛶࢆᣢࡘ㸬༡ഃᒣ⭡ࡢࡶࡢࡣᴫࡡ Walker㸦1971㸧ࡢࠕFlowࠖ ࡢ㡿ᇦࣉࣟࢵࢺࡉࢀ㸪ⅆཱྀࡽࡢ㊥㞳ᛂࡌࡓ⣔⤫ⓗ࡞ኚࡣ☜ㄆ࡛ࡁ࡞࠸㸬ࡇࡢⅆ○ὶ ࡣ㸪ศ⣭ࡀാࡃ๓ᄇ↮ᰕࡢẚ㍑ⓗప࠸㒊ศࡀᔂቯࡋࡓ㸦ࡶࡋࡃࡣⅆཱྀࡽ┤᥋⁄ࢀฟࡋࡓ㸧 ࡇ࡛ᙧᡂࡉࢀ㸪ẚ㍑ⓗప㏿ࡔࡗࡓྍ⬟ᛶࡀ࠶ࡿ㸬ࡇࡢࢱࣉࡢⅆ○ὶ࡛ⅆཱྀ㏆ഐࢢࣝ ࢳࢿ࣮ࢺࡀᙧᡂࡉࢀࡓ㸬ᑠつᶍ࡞ⅆ○ὶࡀ㐃⥆ⓗሁ✚ࡍࢀࡤ㸪࣮ࣟࣈࡀ⣼✚ࡍࡿᵓ㐀ࡸᡂ ᒙᵓ㐀ࡀ⏕ࡌࡿࡔࢁ࠺㸬ࡲࡓ㸪ᒣయ㒊࡛ࡣᴫࡡᩳ㠃ୖᖹ⾜ሁ✚ࡍࡿࡀ㸪พᆅᙧẚ㍑ⓗ ཌࡃሁ✚ࡍࡿࡇ࡛ⅆཱྀࡽ㞳ࢀࡓሙᡤ࡛ࡶࢢࣝࢳࢿ࣮ࢺࢆᙧᡂࡋ㸪ࡉࡽᒣ⭡ࡸᒣ㯄ࡲ ࡛ὶୗࡋࡓࡶࡢࡀ㸪ᙅ㹼㠀⁐⤖ࡢⅆ○ὶࡋ࡚࣮࢞ࣜࡸἑࢆᇙࡵࡓ⪃࠼ࡽࢀࡿ㸬 す㹼ഃᒣ㯄ࡢࡶࡢࡣ㸪㝆ୗࢸࣇࣛࡸᒣయ㒊ẚ㍑ࡍࡿ㸪ࡸࡸศ⣭ࡀᝏࡃ⢏ᚄࡀ⢒࠸ࡀ㸪 ༡ഃᒣ⭡ࡢⅆ○ὶẚ㍑ࡍࡿ᫂ࡽศ⣭ࡀⰋࡃ㸪 ࠕFlowࠖࠕFallࠖࡢ୰㛫㡿ᇦࡽࠕFallࠖ ࡢ㡿ᇦࡅ࡚ࣉࣟࢵࢺࡉࢀࡿ㸬ࡇࡢⅆ○ὶࡣ㸪ศ⣭ࡢ㐍ࢇࡔ㒊ศࡀᄇ↮ᰕࡽศ㞳ࡋ࡚⏕ ࡌࡓྍ⬟ᛶࡀ࠶ࡿ㸬すᑐ㠃ࡍࡿ୰ᓅࡢᒣయᩳ㠃ࢆ㏺࠸ୖࡀࢀࡓࡢࡣ㸪ᄇ↮ᰕࡽࡢᔂቯ 㧗ᗘࡀ㧗ࡃ㸪ẚ㍑ⓗ㧗㏿࡛ὶୗࡋࡓࡇࢆ♧၀ࡍࡿ㸬୰ᓅᒣయᩳ㠃ୖ㏺࠸ୖࡀࡗࡓⅆ○ὶ ᮏయࡀṧᏑ࡛ࡁ࡞ࡗࡓࡼ࠺㸪ᚚ㖊ⅆᒣࡢᒣయᩳ㠃࡛ࡶⅆ○ὶࡀṧࡽ࡞ࡗࡓࡢ࡛࠶ࢁ࠺㸬 ࡇࡢࢱࣉࡢⅆ○ὶࡣⅆཱྀ㏆ഐ㢧ⴭ࡞ࢢࣝࢳࢿ࣮ࢺࢆᙧᡂࡋ࡚࠸࡞࠸⪃࠼ࡽࢀࡿ㸬 4㸬࠾ࢃࡾ 106 㹼107 m3 ࣮࢜ࢲ࣮ࡢ‽ࣉࣜࢽ࣮ᘧᄇⅆ࡛࠶ࡿ ThT-c ࡢᄇⅆ࡛ࡣ㸪ᄇ↮ᰕࡢᔂቯ㧗ᗘࡀప ࠸ⅆ○ὶ㸪ࡶࡋࡃࡣ㸪ⅆཱྀࡽ┤᥋⁄ࢀฟࡍࡼ࠺࡞ⅆ○ὶࡀⅆཱྀ㏆ഐ࡛⣼✚ࡋࢢࣝࢳࢿ࣮ ࢺࢆᙧᡂࡋ࡚࠸ࡿࡼ࠺࡛࠶ࡿ㸬୍᪉㸪ᄇ↮ᰕࡢᔂቯ㧗ᗘࡀẚ㍑ⓗ㧗࠸ⅆ○ὶࡣ㸪ࡼࡾ㐲᪉ࡲ ࡛฿㐩ࡋ࡚࠸ࡿࡀ㸪ⅆཱྀ㏆ഐࡸᒣయᩳ㠃ࡣሁ✚ࡏࡎ㸪ࢢࣝࢳࢿ࣮ࢺࡶᙧᡂࡉࢀ࡞ࡗࡓ ᛮࢃࢀࡿ㸬㟝ᓥⅆᒣ⩌࡛ࡣ㸪ከࡃࡢⅆᒣ࡛ࢢࣝࢳࢿ࣮ࢺࡀほᐹ࡛ࡁ㸪ᑡ࡞ࡃࡶ㧗༓✑ ᓠࡸ᪂⇞ᓅ࡛ࡶ 106 㹼107 m3 ࣮࢜ࢲ࣮ࡢ‽ࣉࣜࢽ࣮ᘧᄇⅆక࠺ⅆ○ὶࡼࡗ࡚㸪ⅆཱྀ㏆ഐ ࢢࣝࢳࢿ࣮ࢺࡀᙧᡂࡉࢀ࡚࠸ࡿ㸬ᚚ㖊ⅆᒣ࡛ࡶᑠつᶍࡔࡀ㝆ୗࢸࣇࣛ㉳※ࡢࢢࣝࢳࢿ࣮ ࢺࡀᏑᅾࡋ㸪ᮏሗ࿌ࡣ㝆ୗࢸࣇࣛ㉳※ࡢࢢࣝࢳࢿ࣮ࢺࡢᏑᅾࢆྰᐃࡍࡿࡶࡢ࡛ࡣ࡞࠸ࡀ㸪 Ᏻᒣᒾ㉁ⅆᒣࡢⅆཱྀ㏆ഐࡣⅆ○ὶ㉳※ࡢࢢࣝࢳࢿ࣮ࢺࡀ࡞ࡾᏑᅾࡍࡿᛮࢃࢀࡿ㸬 ⅆཱྀ㏆ഐࡢࢢࣝࢳࢿ࣮ࢺࢆ㸪㟢㢌༢࡛㝆ୗࢸࣇࣛ㉳※ⅆ○ὶ㉳※ุ᩿ࡍࡿࡇࡣ -9- ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ᅔ㞴࡞ࡇࡀከ࠸ࡀ㸪ᄇⅆᵝᘧࡀ‽ࣉࣜࢽ࣮ᘧᄇⅆ㸦ᑡ࡞ࡃࡶ 106 㹼107 m3 ⛬ᗘ㸧࡛࠶ࡿࡇ 㸪ᒣ⭡ࡸᒣ㯄ⅆ○ὶࡀศᕸࡍࡿࡇࡀ㸪᭷ຠ࡞ุ᩿ᮦᩱ࡞ࡿ⪃࠼ࡿ㸬 ┿ 1 ⅆཱྀ⦕࡛ࡳࡽࢀࡿࢢࣝࢳࢿ࣮ࢺ㸦ThT-c㸧 ┿ 2 ┿ 1 ࡢࢢࣝࢳࢿ࣮ࢺྠᒙ‽ࡢᮎ➃㒊࡛ࡳࡽࢀࡿᑠつᶍ࡞࣮ࣟࣈ㸦ThT-c㸧 - 10 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ┿ 3 ⅆཱྀ㏆ഐ࡛ࡳࡽࢀࡿࢢࣝࢳࢿ࣮ࢺ㸦ThT-c㸧 ┿ 4 ┿ 3 ࡢࢢࣝࢳࢿ࣮ࢺྠᒙ‽ࡢᮎ➃㒊࡛ࡳࡽࢀࡿཌ࠸ࢢࣝࢳࢿ࣮ࢺ㸦ThT-c㸧 - 11 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ┿ 5 ࢢࣝࢳࢿ࣮ࢺࡢ⏘≧㸦ThT-c㸧 ┿ 6 ࢢࣝࢳࢿ࣮ࢺࡢ⏘≧㸦ThT-c㸧 - 12 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ┿ 7 ᶆ㧗 1110~1050m ㏆࠾ࡅࡿⅆ○ὶࡢ⏘≧㸦ThT-c㸧 ┿ 8 ୰ᓅᒣయᩳ㠃ୖศᕸࡍࡿⅆ○ὶࡢṧᏑሁ✚≀㸦ThT-c㸧 - 13 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 1-05 㨣⏺࢝ࣝࢹࣛ㸪ᖾᒇⅆ○ὶࡼࡿᆅᒙᶓ㌿⌧㇟ ᡂᑿⱥோ㸦Ṋᒸྎ㧗ᰯ㸧 Overturned strata caused by Koya ignimbrite from Kika caldera H. Naruo (Takeokadai Senior High School) 㸯 ࢝࣍ࣖᄇⅆࡢ᥎⛣ 7300 ᖺ๓㨣⏺࢝ࣝࢹ࡛ࣛⓎ⏕ࡋࡓつᶍ࡞࢝ࣝࢹࣛᄇⅆࡣ୍⯡࢝࣍ࣖᄇⅆࡼࡤࢀ㸪 ୍㐃ࡢᄇฟ≀ࡣ㨣⏺࢝࣍ࣖࢸࣇࣛ⛠ࡉࢀࡿ㸦⏫⏣࣭᪂㸪2003㸧 㸬ึᮇࡢࣉࣜࢽ࣮ᘧᄇⅆ ࡛ࡣᖾᒇ㝆ୗ㍍▼㸦Ky-p㸧ࡀᄇฟࡋ㸪ࡑࡢᚋ㸪つᶍ࡞ⅆ○ὶࡀⓎ⏕ࡋᖾᒇⅆ○ὶሁ✚≀㸦Ky㸧 ࡀᙧᡂࡉࢀ㸪ᴟࡵ࡚ⷧࡃᣑࡀࡾሁ✚ࡋࡓ㸦Ᏹ㸪1973㸧㸬ୖ✵⯙࠸ୖࡀࡗࡓ⣽⢏ⅆᒣ⅊ࡣ ࢝࣍ࣖⅆᒣ⅊㸦K-Ah㸧ࡼࡤࢀ㸪ᮾᆅ᪉ࡲ࡛ศᕸࡍࡿ㸦⏫⏣࣭᪂㸪1978㸧 㸬ᄇⅆࡢ㏵୰࡛ ࡣᄇ♟⌧㇟ࢆక࠺ࡼ࠺࡞ 2 ᅇࡢᆅ㟈ࡀⓎ⏕ࡋࡓ㸦ᡂᑿ࣭ᑠᯘ㸪2002㸧㸬 㸰 ᖾᒇⅆ○ὶࡼࡿᆅᒙᶓ㌿ Ky ࡀሁ✚ࡋࡓ⠊ᅖ࡛ࡣ㸪ࡑࢀࡼࡾୗࡢ Ky-p ᒙ࠾ࡼࡧྂᅵተᒙࡀ㸪ᒁ㒊ⓗᩘ 10r㹼ᆶ ┤ᶓ㌿ࡍࡿᆅᒙᶓ㌿⌧㇟ࡀㄆࡵࡽࢀࡿ㸬ᆅᒙᶓ㌿ࡢ᪉ྥࡣ࠾࠾ࡴࡡ༡ࡽ࡛࠶ࡿ㸬 A distribution map of Overturned strata caused by Koya ignimblite - 14 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 㨣⏺࢝ࣝࢹࣛࡢ㒊⨨ࡍࡿ⸃ᦶ༙ᓥ༡㒊࡛ࡣ㸪ᣦᐟᆅ᪉࠾ࡼࡧ▱ぴ࣭ᕝ㎶ᆅ᪉ࡢ㑇㊧ ࡛ Ky ࡼࡿᆅᒙᶓ㌿ࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸬࠼ࡤ㸪༡ᕞᕷ㏕℩ᡞᡤᅾࡍࡿ๓ཎ㑇㊧⩌࡛ ࡣ㸪ᖹᆠ࡞ྎᆅୖ࡛ከᩘࡢᆅᒙᶓ㌿ࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸦▱ぴ⏫ᩍ⫱ጤဨ㸪2003㸧㸬㑇㊧⩌ࡢ ୍ࡘ࡛࠶ࡿᇽᒣ㏕㑇㊧࡛ࡣ㸪㨣⏺࢝࣍ࣖࢸࣇࣛࡢ Ky ࢆࡣࡂྲྀࡗࡓ⦖ᩥ௦᪩ᮇᚋ༙ࡢ㯮 Ⰽ⭉᳜ᅵᒙ⾲㠃࡛㸪ᆅᒙᶓ㌿ࡀ☜ㄆࡉࢀࡓ㸬ᆅᒙᶓ㌿ࡣᱜᓥ⸃ᦶࢸࣇࣛ(Sz-S)ᒙ┤ୗࡢ⢓㉁ࣟ ࣮࣒ᒙࡽጞࡲࡾ㸪㯮Ⰽ⭉᳜ᅵᒙࡲ࡛ཬࢇ࡛࠸ࡿ㸬ࡑࢀࡒࢀࡢᆅᒙᶓ㌿᪉ྥࡣ㹼すኚ ᐩࡴࡀ㸪࠾࠾ࡼࡑࡢഴྥࡋ࡚ࡣす᪉ྥ࡛࠶ࡿ㸬 ᆅᒙᶓ㌿ࡣ㝮༙ᓥ༡㒊࡛ࡶ☜ㄆࡉࢀ࡚࠸ࡿ㸬࠼ࡤ㸪༡㝮⏫୰ཎ㑇㊧࡛ࡣከᩘࡢᆅ ᒙᶓ㌿ࡀ☜ㄆࡉࢀࡓ㸦᰿༨⏫ᩍ⫱ጤဨ㸪2000㸧㸬୰ཎ㑇㊧࡛ࡣ㨣⏺࢝࣍ࣖࢸࣇࣛୗ 㸪ྂ࠸᪉ࡽΎぢᓅࢸࣇࣛ㸪㝮㝆ୗ㍍▼࣭ධᡞⅆ○ὶሁ✚≀㸪⢓㉁࣮࣒ࣟᒙ㸪SZ-S㸪㯮 Ⰽ⭉᳜ᅵᒙࡀ㡰ሁ✚ࡍࡿ㸬㑇㊧࡛᭱ࡶつᶍ࡞ᆅᒙᶓ㌿࡛ࡣ㸪Ύぢᓅࢸࣇࣛࡲ࡛ࡢྛᒙࡀ ୍య࡞ࡗࡓࣈࣟࢵࢡࢆᙧᡂࡋ㸪⣙ 45rࡢゅᗘ࡛ᶓ㌿ࡋ࡚࠸ࡿ㸬ᶓ㌿ࡋࡓࣈࣟࢵࢡࡢヲ⣽࡞ ほᐹ࡛ࡣ㸪ཌࡉ 30cm ࡢ Ky-p ࡶᶓ㌿ࡋ㸪ࡑࡢ㒊ศ࡛ࡣᡂᒙᵓ㐀ࡀⴭࡋࡃࡉࢀ࡚࠸ࡿ㸬ᶓ㌿ ࡋࡓࣈࣟࢵࢡࡣ Ky ࠾ࡼࡧ K-Ah ࡼࡾそࢃࢀ࡚࠸ࡿ㸬 㑇㊧༡す㒊࡛ࡣ⣙ 50㹫㸰㸯ಶ⛬ᗘࡢྜ࡛ᆅᒙᶓ㌿ࡀᏑᅾࡋࡓࡀ㸪ࡑࡢᖹ㠃ᙧែࡣᙧ ࡞࠸ࡋࡣᴃᙧ࡛㸪᭱㛗㸳㹫ࡽ㸯㹫⛬ᗘࡲ࡛つᶍࡣᵝࠎ࡛࠶ࡗࡓ㸬㑇㊧ෆ࠾ࡅࡿᆅᒙ ᶓ㌿ࡢศᕸࡣつ๎࡛㸪㞟୰ࡸᐃྥᛶࡣㄆࡵࡽࢀ࡞࠸ࡇࡽ㸪ே㢮άືࡼࡿ㑇ᵓ࡛ࡣ࡞ ࠸ุ᩿ࡉࢀࡿ㸬ᶓ㌿ࡢ᪉ྥࡣ࠾࠾ࡴࡡᮾ᪉ྥ࡛࠶ࡿࡀ㸪⸃ᦶ༙ᓥࡢᇽᒣ㏕㑇㊧ྠᵝ㸪 ಶࠎࡢᆅᒙᶓ㌿ࡣᚲࡎࡋࡶྠ୍᪉ྥࢆ♧ࡍࡣ㝈ࡽ࡞࠸ࠋ࿘㎶ࡢᆅᙧࡢᙳ㡪ࡸⅆ○ὶෆ㒊ࡢ ὶ≧ἣࢆᫎࡋ࡚࠸ࡿᛮࢃࢀࡿࡀ㸪࠾࠾ࡼࡑࡢഴྥࡋ࡚㨣⏺࢝ࣝࢹࣛᑐ᪉ྥᶓ ㌿ࡋ࡚࠸ࡿ㸬 㸱 ᖾᒇⅆ○ὶࡼࡿᆅᒙᶓ㌿ࡢ㐣⛬ 㑇㊧࡛ࡢほᐹࡼࡿ㸪㨣⏺࢝࣍ࣖᄇⅆࡢึᮇᄇฟ≀࡛࠶ࡿ Ky-p ࡶᶓ㌿ࡋ࡚࠸ࡿࡇ㸪 Ky ☜ᐇそࢃࢀࡿࡇࡽᆅᒙᶓ㌿ࡢࢱ࣑ࣥࢢࡣ Ky-p ࡢ㝆ୗ┤ᚋุ᩿ࡉࢀࡿ㸬ከࡃ ࡢ࡛ᶓ㌿ࡋࡓྂᅵተᒙࣈࣟࢵࢡࡢ㝽㛫ࢆ Ky ࡀᇙࡵࡿࡼ࠺ධࡾ㎸ࢇ࡛࠸ࡿࡇࡽ㸪Ky ࡼࡾᶓ㌿ࡀ⏕ࡌࡓᚋ㸪ᘬࡁ⥆ࡁὶ㉮ࡋ࡚ࡁࡓ Ky ࡀ㝽㛫ࢆᇙࡵሁ✚ࡋࡓุ᩿ࡉࢀࡿ㸬 ࡇࡢࡼ࠺࡞ Ky-p㸪Ky ࡢ⿕そ㛵ಀ㸪ᆅᒙᶓ㌿ࡀ⣙ 50㹫㸰ࡈᏑᅾࡍࡿࡇ㸪ᶓ㌿ࡋࡓ ࣈࣟࢵࢡࡢ୰ᚰᶞᮌࡢ㊧⪃࠼ࡽࢀࡿ⭉᳜ᅵተࡀᏑᅾࡍࡿ࡞ࡽ㸪ᙜࡢᆅ⾲㠃 ⏕࠼࡚࠸ࡓᶞᮌࡀ㸪Ky ࡼࡿ┤ᧁࢆཷࡅ᰿㖊ࡈ࡞ࡂಽࡉࢀ㸪ᆅᒙᶓ㌿ࡀᙧᡂࡉࢀࡓุ ᩿ࡉࢀࡿ㸬 - 15 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 1-06 ⇕࣑ࣝࢿࢵࢭࣥࢫ㸦TL㸧ᖺ௦࠾ࡼࡧᒾᏛ⤌ᡂࡼࡿ ᯇࡢྎᒾᒌ࡞ࡔࢀሁ✚≀ࡢ⤥※᥎ᐃ ᆏཱྀ ᕦ࣭ᰆཎ㞞ᶞ࣭ᒣᓮᆂ࣭ዟ㔝 㸦⚟ᒸ࣭⌮㸧 Source of Matsunodai debris avalanches deposit inferred from thermoluminescence age and chemical composition, Kuju volcanic group, central Kyushu, Japan T. Sakaguchi, M. Yuhara, K. Yamasaki and M. Okuno (Fukuoka Univ.) ᯇࡢྎᒾᒌ࡞ࡔࢀሁ✚≀㸦MDA㸧ࡣ㸪୰㒊ᕞ⨨ࡍࡿ㔜ⅆᒣ⩌ࡢ㯄ศᕸࡍࡿᒾ ᒌ࡞ࡔࢀ࡛࠶ࡿ㸬ࡑࡢ⤥※ࡣ≉ᐃࡉࢀ࡚࠸࡞࠸㸬ࡑࡇ࡛㸪ᨵࡵ࡚ MDA ࡢෆ㒊ᵓ㐀㸪ሁ✚≀࿘ ㎶ࡢἑᒣ㸪୕ಛᒣすᓠ㸦ྂ࠸୕ಛᒣ㸧ࡢ㔝እㄪᰝࢆ⾜࠸㸪MDA ᑐẚࡉࢀࡿሁ✚≀ࢆୗ ἑ⁐ᒾࡢୖⓎぢࡋࡓ㸬 TL ᖺ௦ᒾᏛ⤌ᡂࡽ MDA ࡢ⤥※ὶୗ㐣⛬ࢆ⪃ᐹࡋࡓࡢ ࡛ሗ࿌ࡍࡿ㸬 ἑᒣࡣᆅᙧⓗ 2 ᯛࡢࣇ࣮ࣟࣘࢽࢵࢺࡀㄆࡵࡽࢀࡿࡀ㸪ᒾ▼ⓗఝ࡚࠸ࡿࡇࡽ୍ᣓ ࡋ࡚ἑ⁐ᒾࡉࢀ࡚ࡁࡓ㸦ᑠ㔝㸪1963㸹ኴ⏣㸪1991㸧 㸬ࡋࡋ㸪ୗ㒊⁐ᒾྎᆅࡢ㛤ᯒᗘࡑ ࡢୖ MDA ᑐẚࡉࢀࡿᔂቯሁ✚≀ࡀࡿ⏘≧ࡽ㸪 ୗἑ⁐ᒾୖἑ⁐ᒾ༊ูࡍࡿ㸬 ୕ಛᒣすᓠࡣୗἑᒣ⁐ᒾࡀᙧᡂࡍࡿ⁐ᒾྎᆅୖ⨨ࡋ㸪㛤ࡃ㤿㋟ᙧ࢝ࣝࢹࣛࡢ୍㒊 ࡀ☜ㄆ࡛ࡁࡿ㸬⌧ᅾࡢ୕ಛᒣࡢഃⅆཱྀࡣୖἑ⁐ᒾࡢ⁐ᒾὶࡀㄆࡵࡽࢀࡿ㸬TL ᖺ௦ࡣ ୗἑ⁐ᒾࡀ⣙ 43㹼44ka,୕ಛᒣすᓠࡀ⣙ 34㹼35ka㸪ୖἑ⁐ᒾࡀ 25㹼28ka ࢆ♧ࡋ㸪ྛⅆᒣ య㸪ᒾయࡢᆅᙧⓗ࡞㡰ᗎㄪⓗ࡛࠶ࡿ㸬 MDA ࡢศᕸᇦࡣὶࢀᒣᆅᙧࡀከᩘᏑᅾࡋ㸪ὶࢀᒣࡢ㛗㍈᪉ྥࡣ ༡᪉ྥ㸪ᮾ ༡ ༡す᪉ྥ㸪す ༡༡ᮾ᪉ྥࡢ 3 ᪉ྥ༟㉺ࡍࡿ㸬✵୰┿ุㄞ࡛ࡣ㸪MDA ࡢሁ✚㠃ࡀ 3 ẁ☜ㄆ࡛ࡁࡿ㸬㹆/L ẚࡣ 0.10 ࡛࠶ࡿ㸬ᒾሢࡣࢪࢢࢯ࣮ࢡࣛࢵࢡᵓ㐀ࡀⓎ㐩ࡋ㸪ከࡃࡢ㟢㢌 - 16 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡛ࡣ㧗 㓟ࢆ♧ࡍ㉥⣸Ⰽࡢⅆ○ὶሁ✚≀ࡢࣈࣟࢵࢡࢆྵࡴ㸬ୖὶ㒊ࡽᮎ➃㒊ࡅ࡚ᒾ ሢࡣᑠࡉࡃ࡞ࡗ࡚࠸ࡁ㸪ᇶ㉁㒊ࡢ㔞ẚࡀቑ࠼ࡿഴྥࡀ࠶ࡿ㸬MDA ᇶ┙ᅵተᒙࡢቃ⏺┦࡛ ࡣ┤ᚄ 5 ௨ୖࡢ♟ࢆྵࡲࡎ㸪ࡼࡾࡁ࡞ᒾሢࡸᒾ∦ࡣሁ✚≀୰ࡢ୰㒊㞟୰ࡍࡿ㸬 MDA ࡣ㸪㯮㞼ẕྵ᭷ᩳ᪉㍤▼༢ᩳ㍤▼ゅ㛝▼Ᏻᒣᒾ࡛▼ᇶࡀࣥࢱ࣮ࢧ࣮ࢱࣝ⤌⧊ ࢆ♧ࡍࡶࡢ㸦A ࢢ࣮ࣝࣉ㸧 㸪㯮㞼ẕྵ᭷༢ᩳ㍤▼ᩳ᪉㍤▼ゅ㛝▼Ᏻᒣᒾ࡛▼ᇶࡀࣁࣟࣆࣜ ࢸࢵࢡ⤌⧊ࢆ♧ࡍࡶࡢ㸦B ࢢ࣮ࣝࣉ㸧ࡀྵࡲࢀࡿ㸬୕ಛᒣすᓠࡣ A ࢢ࣮ࣝࣉ㸪ୗἑ⁐ᒾ ࡣ B ࢢ࣮ࣝࣉࡢᏳᒣᒾ࡛ᵓᡂࡉࢀࡿ㸬A ࢢ࣮ࣝࣉ࠾ࡼࡧ B ࢢ࣮ࣝࣉࡢ SiO2 ྵ᭷㔞ࡣ㸪ࡑࢀ ࡒࢀ 59.8㹼61.5wt.%㸪58.6㹼59.2wt.%࡛࠶ࡿ㸬A ࢢ࣮ࣝࣉࡣ⣙ 34㹼37ka,B ࢢ࣮ࣝࣉࡣ⣙ 41㹼 45ka ࡢ TL ᖺ௦ࢆ♧ࡍ㸬 ୕ಛᒣࡢ࿘㎶ࡣ୕ಛᒣすᓠࡢ⁐ᒾࢻ࣮࣒ࡀᔂቯࡋ࡚ᙧᡂࡉࢀࡓⅆ○ὶࡀሁ✚ࡋ࡚࠸ࡿ 㸦㛗ᒸ࣭ዟ㔝㸪2014㸧 㸬ࡇࡢࡼ࠺࡞ⅆ○ὶሁ✚≀ࢆᒣయᔂቯྲྀࡾ㎸ࢇࡔࡶࡢࡀ MDA ୰ࡢ ⅆ○ὶࣈࣟࢵࢡ࡛࠶ࡿྍ⬟ᛶࡀ㧗࠸㸬ࡇࢀࡽࡢ≉ᚩࡽ㸪MDA ࡢὶືᶵᵓࡋ࡚ࣉࣛࢵࢢࣇ ࣮ࣟࣔࢹࣝ㸦୕ᮧ㸪1988㸧ࡀᙜ࡚ࡣࡲࡿ㸬⤥※ࡣ୕ಛᒣすᓠ࡛࠶ࡿ⪃࠼ࡽࢀ㸪 ὶୗࡲ ࡛ࡢࣉࣟࢭࢫࡣୗἑ⁐ᒾࡀ⁐ᒾྎᆅࢆᙧᡂࡋࡓᚋ㸪ࡑࡢୖ୕ಛᒣすᓠࢆᙧᡂࡍࡿ⁐ᒾࢻ ࣮࣒ࡀᡂ㛗ࡋ࡚ᒣయᔂቯࢆ㉳ࡇࡋ㸪࿘㎶ࡢⅆ○ὶሁ✚≀ࢆࡾ㎸ࢇ࡛ MDA ࢆ⌧ᅾࡢᆅᇦ ሁ✚ࡉࡏࡓ㸬MDA ᇶᗏ㒊ࡢ᩿ᛂຊࡼࡾ㸪ᇶ┙࡛࠶ࡿ B ࢢ࣮ࣝࣉࡢᏳᒣᒾࡀࡦࡁࡣࡀࡉ ࢀ㸪MDA ྲྀࡾ㎸ࡲࢀࡓ㸬ࡑࡢᚋࡍࡄ୕ಛᒣ⁐ᒾࢻ࣮࣒ࡀᡂ㛗ࡋ࡚ᔂቯⅆཱྀࢆࡰᇙ✚ࡋ㸪 ᭱ᚋୖἑ⁐ᒾࡀୗἑ⁐ᒾࡢ୍㒊ࢆそ࠺ᙧ࡛ഃὶࢀࡓࡢࡔ⪃࠼ࡽࢀࡿ㸬 MDA ࡢὶୗ㐣⛬ࡣ㸪ୗἑ⁐ᒾࢆそࡗ࡚ὶୗࡋࡓὶࢀ୕ಛᒣすᓠࡽす㯄ࡢ⦆ᩳ㠃ὶ ୗࡋࡓὶࢀࡢ 2 ✀㢮࠶ࡿ⪃࠼ࡽࢀࡿ㸬3 ẁࡢሁ✚㠃ࡢ࠺ࡕ୰ẁ㠃ࡢὶࢀᒣ㛗㍈᪉ྥࡣ㸪᥎ ᐃࡉࢀࡿὶୗ᪉ྥ㸦す-༡༡ᮾ᪉ྥ㸧┤ࡋ࡚࠾ࡾ㸪ᒾሢࡀ㛗㍈᪉ྥࢆ㍈ᅇ㌿ࡋࡘࡘ ὶୗࡋࡓࡇࡀ♧၀ࡉࢀࡿ㸬 - 17 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 Fig. 1 Thermoluminesence age of the Matsunodai Debris Avalanches Deposit. - 18 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 2-01 㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢసᡂࡣ࡞ࡐᅔ㞴㸽㸦2㸧 ᶓ⏣ಟ୍㑻㸦ඖ ᓥ᰿Ꮫ࣭⥲ྜ⌮ᕤ㸧 Difficulties in construction of geological exposures database (2) S. Yokota (Shimane Univ.) 1㸬ᇶ♏ࢹ࣮ࢱࡢ౯್㟢㢌ࢹ࣮ࢱ࣮࣋ࢫ ᪥㸪ᆅᙧ࣭ᆅ㉁㛵㐃ࡋࡓᵝࠎ࡞ࢹ㸫ࢱ࣮࣋ࢫࡀ♫῝ࡃᾐ㏱ࡋ㸪ࣥࢱ࣮ࢿࢵࢺࢆ ࡋ࡚ά⏝ࡉࢀ࡚࠸ࡿ㸬ࡋࡋ㸪ࡑࡢከࡃࡣࢩࢫࢸ࣒ࡋ࡚࠺ࡲࡃᶵ⬟ࡋ࡚࠸࡚ࡶ㸪ࢹ࣮ࢱ ࡢ୰㌟ࡸ㉁㛵ࡋ࡚ࡣㄢ㢟ᒣ✚࠸࠺ࡢࡀᐇែ࡛࠶ࢁ࠺㸬➹⪅ࡀࡇࡢᩘᖺ㛫ࢃࡗ࡚ࡁࡓ ࡶࡢ⮬↛⅏ᐖࡢࢹ࣮ࢱ࣮࣋ࢫࡀ࠶ࡿࡀ㸪ࡇࢀ࡛ࡶᇶ♏ࢹ࣮ࢱࡢ㔜せᛶࡶࡑࢀࡓ ࡾ╔ࡃࡇࡢᅔ㞴ࡉࢆ③ឤࡋࡓ㸬ὥỈ㸪ᆅ㟈㸪ὠἼ㸪ᄇⅆ࡞ࡼࡿ⅏ᐖグ㘓ࡣྛᆅከ ᩘᩓᅾࡍࡿࡀ㸪༙ࡣఏ⪺グ㘓࡛࠶ࡾ㸪ఏ㐩㐣⛬ࡢࣇࣝࢱࣜࣥࢢ࡛ෆᐜࡸ㉁ࡣࡁࡃኚ ࡋ࡚࠸ࡿ㸬 ᆅ㉁ᅗ㛵㐃㈨ᩱࡶ⭾࡞ᩘࡀ⏬ീ࡞ࡢࡓࡕ࡛බ㛤ࡉࢀ㸪ᐜ᫆ࢡࢭࢫ࡛ࡁࡿࡼ࠺ ࡞ࡗࡓࡀ㸪ᐊෆ࡛ࡢศᯒ್➼ࢆ㝖ࡅࡤ㸪ࡑࢀࡽࡢከࡃࡣ㔝እࢹ࣮ࢱࡀᇶ♏࡞ࡗ࡚࠸ࡿ㸬 ࡇࡢࡼ࠺ࡳࢀࡤ㸪㔝እࡽ࠸ࡋ࡚౯್࠶ࡿࢹ࣮ࢱࢆ▷ᮇ㛫⥙⨶ⓗྲྀᚓࡍࡿࡀࡇ ࡢศ㔝ࡢⓎᒎࢆᕥྑࡍࡿ࠸࠼ࡼ࠺㸬 1990 ᖺ௦㟢㢌ࢹ࣮ࢱ࣮࣋ࢫᵓ⠏ࡢ㛵ᚰࡀ㧗ࡲࡗࡓࡀ㸦ᶓ⏣㸪1996㸹ᶓ⏣࣭༖ᮏ㸪 1997㸪బ㔝㸪1997 ࡞㸧㸪ࡇࢀࡣ㸪ࢃࡀᅜ࡛ࡣ㟢㢌ࢹ㸫ࢱࡣ」ᩘࡢᶵ㛵ࡸಶேࡼࡗู࡚ࠎ ᚓࡽࢀ࡚࠸ࡿࡇࡽ㸪ᇶ♏ࢹ࣮ࢱࡋ࡚ࡑࢀࡽࢆ㞟✚ࡋ࡚౪ࡍࢀࡤ㸪ᆅ㉁Ꮫྛศ㔝ࡢⓎ ᒎࡶ㈨ࡍࡿࡢ⪃࠼ࡽ࡛࠶ࡗࡓ㸬ࡋࡋ㸪㟢㢌࠸࠼ࡶ✵㛫ෆ࡛ࡣࠕⅬ࡛ࠖࡣ࡞ࡃ㸪 㸱ḟඖⓗ࡞ᗈࡀࡾࢆࡶࡗ࡚࠸ࡿࡋ㸪ᒾ▼ࢱࣉ㸪ᒾ┦࣭ᒙ┦ຍ࠼࡚᪉ྥࡢࢹ࣮ࢱࡸᒙᗎ㸪 ᵓ㐀㸪㈏ධ➼㛵ࡍࡿ┦㛵ಀࡢࢹ࣮ࢱࢆྵࢇ࡛࠸ࡿ㸦ᶓ⏣㸪1996㸧 㸬ࡉࡽ㸪⌧ᐇࡢᆅ㉁ ᅗసᡂ㐣⛬࡛ࡣ㞄᥋㟢㢌㛫ࡢࢹ࣮ࢱẚ㍑ᇶ࡙࠸࡚ᒁᡤⓗ࡞ᆅ㉁ࣔࢹࣝࢆヨ⾜㘒ㄗⓗᵓ⠏ 㸪ࡇࢀࡽࡢᑐฎࡀ㟢㢌ࢹ࣮ࢱ࣮࣋ࢫᵓ⠏࠾ࡅࡿᅔ㞴 ᅗ-1㸧 ࡋ࡚࠸ࡃࢫࢸࢵࣉࡶ࠶ࡿࡀ㸦ᅗ ࡞ㄢ㢟࡛࠶ࡗࡓ㸬 㸰㸬㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢ⏝ྲྀࡾᕳࡃ⎔ቃࡢኚ ࡇ࠺ࡋࡓㄢ㢟ࡣ᪥࡛ࡶࡁࡃࢃࡿࡶࡢ࡛ࡣ࡞࠸ࡀ㸪㟢㢌ࢹ㸫ࢱ࣮࣋ࢫࡢ⏝┠ⓗࡸ⎔ ቃࡣࡇࡢ 20 ᖺ㛫ࡁࡃኚࡋ࡚ࡁࡓ㸬♫య⮬↛ࣁࢨ࣮ࢻ⅏ᐖ㛵ࡍࡿ㛵ᚰࡀ㧗 - 19 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡲࡾ㸪ᵓ㐀≀ࡸࣥࣇࣛᩚഛ㛵ࡋ࡚ࡶᑗ᮶ࡢࣁࢨ࣮ࢻண ࡢᚲせᛶࡀ㧗ࡲࡗ࡚ࡁࡓ㸬ከ ᵝ࡞ ᅗ-1 㟢㢌ࢹ࣮ࢱ࣮࣋ࢫ࠾ࡅࡿࢹ࣮ࢱࡢ㞟✚㸦ᶓ⏣㸪1996㸧 㸬 ୍⯡ࡣ(a)ࡢࡼ࠺࡞༢⣧࡞ࡶࡢ࡛ࡣ࡞ࡃ㸪(b)ࡢࡼ࠺㞄᥋㟢㢌㛫࡛ᒁᡤ ⓗ࡞ᆅ㉁ࣔࢹࣝࢆᵓ⠏ࡋ࡚࠸ࡃ㸬 ࣁࢨ࣮ࢻ࣐ࢵࣉࡢᵓ⠏බ⾲ࡀࡑࢀࢆࡅ࡚࠾ࡾ㸪ࡑࢀࡽࡣࢹ࣮ࢱ࣮࣋ࢫࡢฟຊ⾲⌧࡛ࡶ ࠶ࡿ㸬ࡲࡓ㸪ࡇࢀ㛵㐃ࡋ࡚㸪┠ⓗࢆ㝈ᐃࡋࡓࢺࣞࣥࢳㄪᰝࡸ࣮࣎ࣜࣥࢢㄪᰝࡀᗈࡃᐇࡉ ࢀࡿࡼ࠺࡞ࡾ㸪ࢺࣞࣥࢳቨ㠃ࡸ࣮࣎ࣜࣥࢢࢥ➼㸪㟢㢌௨እࡢ㔝እࢹ࣮ࢱࡀᛴቑࡋ࡚ࡁ ࡓ㸬ά᩿ᒙࡑࢀࢆそ࠺ࢸࣇࣛࡢ㔝እࢹ࣮ࢱ࡛ࡶࡇࡢ✀ࡢࡶࡢࡀ༙ࢆ༨ࡵࡿࡼ࠺࡞ࡗ࡚ ࠸ࡿ㸬 ࡇ࠺ࡋࡓ⏝㠃ࡢኚࢆ⪃៖ࡍࢀࡤ㸪㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢᵓ⠏ࡣ༢ᆅ㉁ᅗసᡂࡢࡓࡵ ࡢᇶ♏ࢹ࣮ࢱࡋ࡚ࡔࡅ࡛࡞ࡃ㸪ᆅ㉁ᅗసᡂࢆ⤒࡞࠸࡛ᐇ♫࡛┤᥋⏝࡛ࡁࡿࢹ࣮ࢱࢆ ᅗ-2㸧㸬ࡇࡢሙྜ㸪ᆅ㉁ࣔࢹࣝᵓ⠏ࡢࢫࢸࢵࣉࢆᚲࡎྵࡴ ࡶᥦ౪࡛ࡁ࡞ࡅࢀࡤ࡞ࡽ࡞࠸㸦ᅗ ࡇࡣ࡞ࡃ࡞ࡿࡀ㸪᪂ࡓ࡞ㄢ㢟ࡑࢀࡢྲྀࡾ⤌ࡳࡀᚲせ࡛࠶ࡿ㸬 㸱㸬ᐇ♫ࡀ┤᥋⏝ࡍࡿ㟢㢌ࢹ࣮ࢱ࣋㸫ࢫࡢㄢ㢟 ᪂ࡓ࡞ㄢ㢟ࡋ࡚㸪㟢㢌ࢹ࣮ࢱࡣྍ⬟࡞㝈ࡾᐇ♫ࡢࢱ࣒ࢫࢣ࣮ࣝ⢭ᗘ㏆࠸ࡓࡕ ࡢࡶࡢ࡛ᚓࡽࢀࡿ㸪࠶ࡿ࠸ࡣࡑࢀኚ࡛ࡁࡿࡇࡀᮃࡲࢀࡿ㸬ࡉࡽ㸪ࢹ࣮ࢱྲྀᚓ ࡣ㸪ᚑ᮶ࡢࡼ࠺࡞ᆅ㉁ᅗసᡂࢆᛕ㢌࠾࠸ࡓᒙᗎࡸᵓ㐀ࡢ⾲⌧ࡢࡓࡵࡔࡅ࡛࡞ࡃ㸪ᒙᗎ ࡽሁ✚㐣⛬㸪࠶ࡿ࠸ࡣᵓ㐀ࡽᵓ㐀㐠ື࠸ࡗࡓᆅ㉁⌧㇟ࡑࡢࡶࡢࢆㄞࡳྲྀࢀࡿࡶࡢ ࡛࡞ࡅࢀࡤ࡞ࡽ࡞࠸㸬㟢㢌ࡋ࡚ಖᏑࡉࢀࡓࠕࡶࡢࠖࡸࠕࡓࡕࠖࢆᚓࡿࡔࡅ࡛࡞ࡃ㸪ࡑ ࢀࡽࢆࡶᐇ♫ࡢࢱ࣒ࢫࢣ࣮ࣝ⢭ᗘ㏆࠸ࡓࡕ࡛ࠕ⌧㇟ࠖࢆ᥎ᐃ࡛ࡁࢀࡤ㸪ᐇ♫ ࡛ࡢ⏝㈨ࡍࡿࡇࢁࡀࡁ࠸㸬 - 20 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ୍᪉㸪ࢺࣞࣥࢳቨ㠃ࡸつᶍ࡞㐨㊰᥀๐㠃ࡢࢹ࣮ࢱࡶ⮬↛㟢㢌ྠᵝྲྀࡾᢅ࠺ᚲせࡀ ࠶ࡿࡋ㸪࣮࣎ࣜࣥࢢࢥࡶ୍ぢ῝ᗘ᪉ྥࡢ୍ḟඖࢹ࣮ࢱࡢࡼ࠺ぢ࠼ࡿࡀ㸪ࢥ୰ࡢ⏘≧ ࡲ࡛ྵࡵࢀࡤ㸪๓⪅ྠᵝࡢྲྀࡾᢅ࠸ࡀᚲせ࡞ࡿ㸬ࡇࡢࡓࡵ㸪ࡇࢀࡽࡘ࠸࡚ࡣ࠸ࡎࢀࡶ ࠕ㟢㢌ࠖྠᵝࡢࢹ࣮ࢱྲྀᚓ࡞ࡢᑐฎࡀᚲせ࡛࠶ࡿ㸬 ㏆ᖺ㸪㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢࢩࢫࢸ࣒ࠕ㛵ಀࡢ௦ᩘࠖࡸࠕࢢࣛࣇ⌮ㄽࠖࡢᑟධࡀヨࡳࡽ ࢀ㸦Ἑす㸪2001,2003 ࡞㸧 㸪ᆅ㉁ࢹ࣮ࢱࡢᩘᏛⓗ⾲⌧ࡣ㐍ᒎࡋࡓࡀ㸪ࡑࢀぢྜࡗࡓࡓࡕ ࡛ࡢࢹ࣮ࢱྲྀᚓࡣᐜ࡛᫆ࡣ࡞࠸㸬ᒙᗎࡸᵓ㐀㸪㈏ධ㛵ಀ࡞㸪ᆅ㉁Ꮫࡢୡ⏺࡛ࡣᴫᛕࡢ」㞧 ࡉᑐᛂࡋ࡚ࢹ࣮ࢱྲྀࡾᢅ࠸ࡢ㞴ࡋࡉࡀᒣ✚ࡍࡿ㸬ࡲࡓ㸪つᶍ࡞㐨㊰᥀๐㠃ࡶྵࡵ࡚㟢㢌 ࡣ㢖⦾⏕ࡲࢀ㸪ࡘᾘኻࡍࡿࡋ㸪ㄪᰝ⪅ࡸㄪᰝࢫࢸ࣮ࢪࡢ㐪࠸ࡼࡗ࡚㟢㢌ࡽᚓࡽࢀࡿ ࢹ࣮ࢱࡀ␗࡞ࡿࡇࡶከࠎ࠶ࡿ㸬 ࡋࡋ㸪㸱ḟඖࢹ࣮ࢱࡢྲྀᚓ᪉ἲ࠾ࡼࡧฟຊ⾲⌧㛵㐃ࡋࡓሗᢏ⾡ࡀⴭࡋࡃ㐍ᒎࡋ㸪 ┿㸪ࣅࢹ࢜㸪ࢫࢣ࣮ࣛࣈࣝ࡞ᆅᙧ࣭✵୰┿ࢹ࣮ࢱࢆేࡏࡓྲྀࡾᢅ࠸ࡶᐜ᫆࡞ࡗ࡚ࡁࡓ ࡇࡽ㸪ୖ㏙ࡋࡓ⏝㠃ࡢኚࡢᑐᛂຍ࠼㸪ࡇࢀࡽࡢᢏ⾡ࢆ⤌ࡳྜࢃࡏࡿࡇ࡛ຠᯝ ⓗ࡞㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡀᒎ㛤࡛ࡁࡿྍ⬟ᛶࡶ࠶ࡿ㸬ᆅ㉁ᅗసᡂࢆ┠ⓗࡋࡓỗ⏝ᛶࡢ㧗࠸㟢 㢌ࢹ࣮ࢱ࣮࣋ࢫᵓ⠏ࡣࡲࡔࡲࡔㄢ㢟ࡀከ࠸ࡀ㸪♫ⓗせồࢆ⪃៖ࡋ࡚⏝┠ⓗࢆ⤠ࢀࡤ㸪 ຠᯝⓗ࡞ࡶࡢࡢᵓ⠏ࡣྍ⬟ࡶࡋࢀ࡞࠸㸬 ᅗ-2 ỗ⏝ᛶࡢ㧗࠸⏝ࢆ┠ᣦࡍሙྜ(A)㸪ᐇ♫࡛ࡢ┠ⓗࢆ⤠ࡗࡓ⏝(B)ࡢ㐪࠸㸬 㸦ᆅ㉁ࣔࢹࣝࡢᵓ⠏) 㺃㺃㺃᪥࡛ࡶ᭱ࡢㄢ㢟 (A)㸦ỗ⏝ᛶࡢ㧗࠸⏝㸧 ᆅ㉁ᅗ 㟢㢌ࢹ࣮ࢱ ࣮࣋ࢫ ᐇ♫࡛ ࡢ⏝㻌 㻌 (B)㸦┠ⓗࢆ㝈ᐃࡋࡓ⏝㸧㻌 ධຊࢹ࣮ࢱࡢከᵝ ᛴቑࡍࡿ࣮࣎ࣜࣥࢢࢥ࣭ ࢺࣞࣥࢳቨ㠃࡞ࡢ㔝እࢹ ࣮ࢱࡶᑐᛂࡍࡿྲྀᚓ᪉ἲ ࡢᶍ⣴ ᪂ࡓ࡞ㄢ㢟 ࣭ᐇ♫ࡢࢱ࣒ࢫࢣ࣮ࣝ⢭ᗘ࡛ࡢ ࢹ࣮ࢱྲྀᚓࡲࡓࡣኚ㸬 ࣭㟢㢌ࡽᆅ㉁⌧㇟ࡢ㧘⢭ᗘ ㄞࡳྲྀࡾ㸬 ỗ⏝ᛶࢆ┠ᣦࡏࡤᆅ㉁ᅗసᡂࡀᚲせ࡞ࡿࡀ㸪ᐇ♫࡛ࡢ┠ⓗࢆ⤠ࡗࡓ⏝࡛ ࡣᚲࡎࡋࡶᆅ㉁ᅗసᡂࢆᚲせࡋ࡞࠸㸬ࡓࡔࡋ㸪ࡑࡢሙྜࡣ᪂ࡓ࡞ㄢ㢟ࡀ Ⓨ⏕ࡍࡿ㸬 - 21 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ᩥ ⊩ Ἑす⚽ኵ㸪2001㸪ಶே⏝㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢタィࡘ࠸࡚㸫㟢㢌ᵓ㐀ࡢᩘᘧ㛵ࡍࡿ⪃ᐹ 㸫㸪ሗᆅ㉁㸪11, 235-240 Ἑす⚽ኵ㸪2003㸪ಶே⏝㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢタィࡘ࠸࡚(2)㸫ᒙᗎࡢ⾲⌧᪉ἲࡘ࠸࡚㸫㸪 ሗᆅ㉁㸪14, 249-258. బ㔝㞞அ㸪1997㸪ࢹࢪࢱࣝࣇ࣮ࣝࢻ࣐ࢵࣉ㸪᪥ᮏሗᆅ㉁Ꮫࢩ࣏ࣥࢪ࣒࢘’97㸪ㅮ₇ ㄽᩥ㞟㸪27-32. ᶓ⏣ಟ୍㑻㸪1996, 㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢసᡂࡣ࡞ࡐᅔ㞴? ሗᆅ㉁㸪7, 297-301. ᶓ⏣ಟ୍㑻࣭༖ᮏ┾㸪1997, ᆅ㉁ࢹ࣮ࢱ࣮࣋ࢫ㸪ᛂ⏝ᆅ㉁㸪38, 153-158. - 22 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 2-02 㟢㢌ሗࡢ㞟ඹ᭷ࡓࡵࡢሗࢧࢺ㞟ᨭࢶ࣮ࣝࡢᩚഛ ዟᮧ 㸦⚟ᒸ࣭⥲ྜሗฎ⌮ࢭࣥࢱ࣮㸧࣭▮⩚⏣ඃ㍤㸦⚟ᒸ࣭ᕤ㸧 㧗ᶫఙᘺ㸦⚟ᒸ࣭ᕤ㸧࣭㭯⏣┤அ㸦⚟ᒸ࣭ᕤ㸧 Preparation of outcrop information site and supporting tools for collecting and sharing M. Okumura (Info. Tech. Center, Fukuoka Univ.), Y. Yahata (Fac. Eng., Fukuoka Univ.), S. Takahashi (Fac. Eng., Fukuoka Univ.), N. Tsuruta (Fac. Eng., Fukuoka Univ.) ⅆᒣᆅ㉁Ꮫ࠾࠸࡚㟢㢌ሗࢆ㍈ࡋࡓ◊✲ࢹ࣮ࢱࡢ㞟࣭✚ࡣ◊✲⪅ಶேࡔࡅ࡛࡞ࡃ 㜵⅏ࡸ࢘ࢺ࣮ࣜࢳࡢ㠃ࡽࡶ㠀ᖖ㔜せ࡛࠶ࡿ㸬ᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ࡛ࡣ㟢㢌ሗ ඹ᭷ࡢⅭࡢ࢙࢘ࣈࢧࢺࢆヨ㦂ⓗබ㛤ࡋ㸪ࢹ࣮ࢱ࣮࣋ࢫᵓ⠏ࡢ᪉㔪ࡘ࠸᳨࡚ウࢆ㐍ࡵ࡚ ࠸ࡿ㸬୍⯡ⓗ◊✲⪅ࡀⓎぢ㸪㞟ࡋࡓ㟢㢌ሗࡣ᳨ドࢆᚓ࡚◊✲ㄽᩥ➼⧳ࡵࡽࢀ㸪බ⾲ ࡉࢀࡿࡇ࡞ࡿࡀ㸪ࡑࡢᩘࡣᴟࡵ࡚㝈ࡽࢀ࡚࠾ࡾ㸪㔝እㄪᰝ࡛ᚓࡽࢀࡓ㟢㢌ሗࡢ༙ࡣ ◊✲⪅ಶேࡢᡭඖ࡛㞟ࡋࡓከ㔞ࡢㄪᰝ⣲ᮦࡋ࡚ᇙࡶࢀ࡚ࡋࡲ࠺ࢣ࣮ࢫࡀከ࠸㸬௬㞟 ࡋࡓ㟢㢌ሗࢆᩚ⌮ࡋ㸪ࢹ࣮ࢱ࣮࣋ࢫࡋ࡚ᗈࡃබ⾲ࡋ࡚ά⏝ࡍࡿࡋ࡚ࡶ㸪㟢㢌ሗࡣᮏ ㉁ⓗ㠀ᐃᆺࡘ⮬⏤ᗘࡢ㧗࠸ࢹ࣮ࢱ࡛࠶ࡿࡓࡵ㸪⦅⧩⪅ẖ㟢㢌ሗࡢ⾲グࡸ⾲⌧ࡀ␗࡞ ࡿࡇࡶከࠎ࠶ࡿ㸬ࡲࡓ㸪ࡑࢀࡽࢆᩚ⌮㸪ᵓ⠏ࡍࡿࡣᑓ㛛ᐙࡼࡿᡭసᴗࢆᚲせࡋ㸪⭾ ࡞ேⓗ࣭㛫ⓗࢥࢫࢺࢆせࡍࡿࡇ࡞ࡿ㸬ࡋࡋ࡞ࡀࡽ㸪ᑡ࡞ࡃࡶ⨨ሗ⣣࡙ࡃ 㟢㢌⏬ീሗࡀබ㛤ࡉࢀࢀࡤ㸪௬㟢㢌ࡀᾘ⁛ࡋ࡚ࡶ࣮࣎ࣜࣥࢢ᥇᥀ࡸࢺࣞࣥࢳㄪᰝࢆ⾜࠺ ࡇࡶྍ⬟࡞ࡿ࡞㸪㟢㢌ࡑࡢࡶࡢࡢᏑᅾᛶࡀグ㘓㸪ඹ᭷ࡉࢀࡿࡇࡣᴟࡵ࡚㔜せ࡛࠶ࡿ ⪃࠼ࡿ㸬 ࡑࡇ࡛ᡃࠎࡣᚑ᮶ࡣ␗࡞ࡿࣉ࣮ࣟࢳ࡛ࡢ㟢㢌ሗࢹ࣮ࢱ࣮࣋ࢫࡢᵓ⠏ࢆヨࡳ࡚࠸ࡿ㸬 ᚑ᮶ࡢᆅ㉁ࢹ࣮ࢱ࣮࣋ࢫ࡛ࡣ㸪⤌⧊ⓗᆅ㉁ࢹ࣮ࢱࡢ㞟ࡸ᳨ドࢆ⾜࠸㸪༑ศ⢭ᰝࡉࢀࡓ ࢹ࣮ࢱࡢࡳࢆබ㛤ࡍࡿ࠸࠺᪉ἲࡀ᥇ࡽࢀ࡚࠸ࡿࡀ㸪ᡃࠎࡢᵓ⠏ࡍࡿࢹ࣮ࢱ࣮࣋ࢫ࡛ࡣ◊✲ ⪅ࢆጞࡵ㸪ᆅ㉁ᏛࡸⅆᒣᏛ⯆ࢆᣢࡘ୍⯡ࡢᕷẸࡢ᪉ࢆྵࡵࡓᕷẸཧຍᆺࡼࡿᆅ㉁ࢹ࣮ ࢱࡢ㞟ሗࡢඹ᭷ࡼࡿࣉ࣮ࣟࢳࢆ┠ᣦࡋࠊ㟢㢌ሗࢆ୰ᚰࡋࡓᆅ㉁ሗࡢ㞟 ඹ᭷ࢆ┠ⓗࡋࡓࢧࢺࠕࡌ࠾ࣟࢢࠖ1ࢆ㛤Ⓨࡋ㸪ࣥࢱ࣮ࢿࢵࢺୖ࡛බ㛤ࡋ࡚࠸ࡿ㸬ࠕࡌ࠾ ࣟࢢࠖࡣ◊✲⪅ࡸᕷẸࡢ᪉ࡽ㸪㟢㢌ሗࢆ୰ᚰࡋࡓᆅ㉁ࢹ࣮ࢱ㸦㟢㢌┿ࡑࡢ ⨨㸧ࡢሗᥦ౪ࢆཷࡅ㸪㟢㢌ሗࢆඹ᭷ࡍࡿࡇࢆ┠ⓗࡋࡓሗࢧࢺ(Fig.1)࡛࠶ࡿ㸬 1 http://www.acrifis-ehai.fukuoka-u.ac.jp/geolog/ - 23 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 㟢㢌┿࡞ࡢሗᥦ౪⪅ࡣ㸪ࣃࢯࢥࣥ࡞ࡽᮏࢧࢺࢡࢭࢫࡋ㸪ᢞ✏࣓ࢽ࣮ࣗ ἢࡗ࡚㟢㢌┿ࢆᥦ౪ࡍࡿ⤌ࡳ࡛࠶ࡿ㸬ࡑࡢ㝿㟢㢌ࡢලయⓗ࡞⨨ࢆᙳ⏬ീᇙࡵ ㎸ࡲࢀࡓ EXIF ሗࡸᥦ౪⪅ࡢᣦ♧ࡽྲྀᚓࡍࡿ㸬ࡲࡓ㸪㟢㢌⏬ീࡢᥦ౪⡆༢࡞ࢥ࣓ࣥ ࢺࡸ࣮࣮࢟࣡ࢻ㸦ࢱࢢ㸧ࡶࡋ࡚ࡶࡽ࠺㸬᭱ᑠ㝈ᗘࡢࡇࢀࡽ⿵㊊ሗࡣ㸪ᚋࠎ࣓ࢱሗ ࡋ࡚⏝ࡋࠊ㞟✚ࡉࢀࡓ㟢㢌ሗࡢ᳨⣴ࡸศ㢮⏝ࡍࡿࡇࢆᐃࡋ࡚࠸ࡿ㸬 ୍᪉㸪ࠕࡌ࠾ࣟࢢࠖࡣ Web ࢧࢺ࡛࠶ࡿᛶ㉁ୖࠊ㟢㢌ሗࡢධຊࡣ Web ࣈࣛ࢘ࢨࢆ⏝࠸ ࡓ⏬ീࢹ࣮ࢱ㸪⨨ሗ➼ࡢࢵࣉ࣮ࣟࢻࡀᚲ㡲࡛࠶ࡿ㸬ࡑࡢࡓࡵ᧯సᛶ࡞ࡢⅬࡽ㔝እ ࡛ࡢ㟢㢌ሗࡢ㞟ࡀ⾜࠸㎞࠸㸬ຍ࠼࡚㸪㟢㢌ࡣ㔝እ࡛ぢࡽࢀࡿࡶࡢ࡛࠶ࡾ㸪㟢㢌ࡢⓎぢ⌧ ሙࡽࢹ࣮ࢱࡢࢵࣉ࣮ࣟࢻࡀ┤᥋⾜࠼ࡿࡇࡀᮃࡲࡋ࠸㸬ࡑࡇ࡛ᡃࠎࡣ㸪ᒇእ࠾ࡅࡿ㟢 㢌ሗࡢ㞟ࢆ⾜࠼ࡿࡼ࠺ࢫ࣐࣮ࢺࣇ࢛ࣥࡽ┤᥋㸪㟢㢌ሗࡢⓏ㘓ࡀ⾜࠼ࡿ 2 ✀㢮 ࡢࣔࣂࣝࣉࣜࢣ࣮ࢩࣙࣥࡢ㛤Ⓨࢆ⾜ࡗࡓ㸬 Fig.1 㟢㢌ሗࢧࢺࠕࡌ࠾ࣟࢢࠖ Fig.2ࠕࡌ࠾ࣟࢢࠖᢞ✏⏝ࣉࣜࢣ࣮ࢩࣙ ࣥ - 24 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 2-03 ◊✲ࢹ࣮ࢱඹ᭷ࡢࡓࡵࡢᆅ⌮ሗࢹ࣮ࢱ࣮࣋ࢫࢧ࣮ࣅࢫࡢᵓ⠏ 㧗ᶫఙᘺ㸦⚟ᒸ࣭ᕤ㸧࣭ዟᮧ 㸦⚟ᒸ࣭⥲ྜሗฎ⌮ࢭࣥࢱ࣮㸧 㭯⏣┤அ㸦⚟ᒸ࣭ᕤ㸧 Development of geo-information database service for data sharing S. Takahashi (Fac. Eng., Fukuoka Univ.), M. Okumura (Info. Tech. Center, Fukuoka Univ.), N. Tsuruta (Fac. Eng., Fukuoka Univ.) ⅆᒣᆅ㉁Ꮫ࠾࠸࡚㟢㢌ሗࢆ㍈ࡋࡓ◊✲ࢹ࣮ࢱࡢ㞟࣭✚ࡣ◊✲⪅ಶேࡔࡅ࡛࡞ࡃ 㜵⅏ࡸ࢘ࢺ࣮ࣜࢳࡢ㠃ࡽࡶ㠀ᖖ㔜せ࡛࠶ࡿ㸬ᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ࡛ࡣ㟢㢌ሗ ඹ᭷ࡢⅭࡢ࢙࢘ࣈࢧࢺࢆヨ㦂ⓗබ㛤ࡋ㸪ࢹ࣮ࢱ࣮࣋ࢫᵓ⠏ࡢ᪉㔪ࡘ࠸᳨࡚ウࢆ㐍ࡵ࡚ ࠸ࡿ㸬ࡇࢀࡲ࡛㸪ⅆᒣ㟢㢌ሗࡢ㞟࣭ඹ᭷ࡢࡓࡵࡢ Web ࢧࢺࠕࡌ࠾ࣟࢢࠖ ࡸ㸪⤒⦋ ᗘሗࡸ௵ពࡢ࣮࣮࢟࣡ࢻ࣭ࢥ࣓ࣥࢺࢆ㟢㢌⏬ീ୍ᣓࡋ࡚ࡍࡿࢶ࣮ࣝࠕo-GIEࠖ࡞ ࡢ㛤Ⓨࢆ⾜ࡗ࡚ࡁࡓ㸬 㟢㢌ሗࡣᮏ㉁ⓗ㠀ᐃᆺࡘ⮬⏤ᗘࡢ㧗࠸ࢹ࣮ࢱ࡛࠶ࡿࡓࡵ㸪⦅㞟⪅ࡼࡗ࡚⾲グࡸ⾲ ⌧ࡀ␗࡞ࡿࡇࡣከࠎ࠶ࡿ㸬ࡲࡓ㸪ࡑࢀࡽࢆᩚ⌮㸪ᵓ⠏ࡍࡿࡣᑓ㛛ᐙࡼࡿᡭసᴗࢆᚲせ ࡋ㸪⭾࡞ேⓗ࣭㛫ⓗࢥࢫࢺࢆせࡍࡿࡇ࡞ࡿ㸬ࡇࡢၥ㢟ᑐࡋ㸪⏝⪅ࡀࢹ࣮ࢱ ࡋࡓ௵ពࡢࢱࢢࢆ⏝࠸࡚⮬ືศ㢮ࡍࡿࡇࡼࡾࢹ࣮ࢱ࣮࣋ࢫసᡂࢆ┬ຊࡍࡿࡇࢆ ⪃࠼ࡿ㸬ࢱࢢࢆ⏝ࡋࡓࢹ࣮ࢱ⟶⌮࡛ࡣ㸪⮬⏤௵ពࡢ࣮࣮࢟࣡ࢻࢆຍࡍࡿࡇࡀ࡛ࡁࡿ ࡢ࡛㸪ࢹ࣮ࢱ㡯┠ࡢෆᐜࡸ㡯┠ᩘ㸪ࣇ࢛࣮࣐ࢵࢺ➼㢌ࢆ↹ࢃࡏࡿࡇࡀ࡞ࡃ㸪ࢱࢢᇶ࡙ ࡃࢹ࣮ࢱ㛫ࡢ㢮ఝᗘィ⟬ࡼࡾ⮬ືศ㢮ࡀྍ⬟࡞ࡿࡓࡵ㸪๓ࡢศ㢮࣭ᩚ⌮ࡀせ㸪࠸ ࡗࡓ࣓ࣜࢵࢺࡀ࠶ࡿ㸬ࣇࣝࡢ✀㢮ࡸ⨨ሗ࡞㸪ᶵᲔⓗฎ⌮࡛ࡁࡿሗࡣ⮬ືⓗ ࢱࢢࡅࡍࡿࡇࡀྍ⬟࡛࠶ࡾ㸪ᡤ᭷⪅ࡸࢡࢭࢫࣞ࣋ࣝࠊⓏ㘓᪥ࠊ᭦᪂᪥ࡣ㞃ࡋࢱࢢ ࡋ࡚ಖᣢࡍࡿ㸬ࡉࡽࡣ㸪ධຊࡉࢀࡓࢥ࣓ࣥࢺ➼ࡢᩥ❶ࡽ⮬ືⓗ㐺ษ࡞࣮࣮࢟࣡ࢻࢆ ᢳฟࡍࡿࡇ࡛㸪ࢱࢢධຊࡢᡭ㛫ࢆ㍍ῶࡍࡿࡇࡶ࡛ࡁࡿ㸬ࡲࡓ㸪ࢹ࣮ࢱࢆᚑ᮶ᆺࡢ㝵ᒙᵓ 㐀࡛ࡣ࡞ࡃࣇࣛࢵࢺ࡞ᵓ㐀ࡋ࡚⟶⌮ࡍࡿࡇࡽ㸪≀⌮ⓗ࡞ࢹ࣮ࢱ⟶⌮ࡢᵓ㐀ࢆ⪃៖ࡍࡿ ᚲせࡀ࡞ࡃ㸪つᶍศᩓࢹ࣮ࢱ⟶⌮ࢩࢫࢸ࣒ࡋ࡚ᵓ⠏ྍ⬟࡞Ⅼࡶ࣓ࣜࢵࢺࡋ࡚ᣲࡆࡽࢀ ࡿ㸬 ࡇࡢࢱࢢࡼࡿࢹ࣮ࢱ࣮࣋ࢫసᡂᡭἲࡢ᭷ຠᛶࢆ᳨ウࡍࡿࡓࡵ㸪ᆅ㉁Ꮫ◊✲ᐊ࠾ࡅࡿ༞ ᴗ◊✲➼ࡢ㛵㐃ࢹ࣮ࢱࢆᑐ㇟ࡋࡓࢹ࣮ࢱ⟶⌮ᨭࢩࢫࢸ࣒ࢆ㛤Ⓨࡋࡓ㸬 ᆅ㉁Ꮫ◊✲ᐊ ࠾࠸࡚㸪༞ᴗ◊✲➼࡛ࡲࡵࡽࢀࡿ◊✲㈨ᩱࡣ⭾࡞ࡶࡢ࡞ࡿࡇࡽ㸪ࡑࢀࡽࡢࢹ࣮ࢱ - 25 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡢᩓ㐓ࢆ㜵ࡂ㸪ࡘ⏝ࢆࡍࡿࡼ࠺࡞ࢹ࣮ࢱ⟶⌮ᡭἲࡢ☜❧ࡣ㔜せ࡞ㄢ㢟࡞ࡿ㸬 ࡲࡓࢹ࣮ࢱࡢ✀㢮ࡋ࡚ࡶ㸪┿ࡸ⏬ീࡔࡅ࡛ࡣ࡞ࡃྛ✀ࢻ࣓࢟ࣗࣥࢺࣇࣝࡸ ᐃ⤖ᯝ ࡢ⏕ࢹ࣮ࢱ࡞ከᒱࢃࡓࡿ㸬ᮏ◊✲࡛ࡣ㸪ࡇࢀࡽࡢⅬࢆ⪃៖ࡋࡓࢹ࣮ࢱ⟶⌮ᨭࢩࢫࢸ࣒ ࢆᵓ⠏ࡋ㸪ᐇ㝿ࡢ㐠⏝ࢆ㏻ࡋ࡚᪂ࡓ࡞ㄢ㢟ࡸᚲせ࡞ᶵ⬟ࢆ᳨ウࡍࡿ㸬 ࡲࡎࡣࠊᇶᮏᶵ⬟ࢆ⤌ࡳ㎸ࢇࡔࣉࣟࢺࢱࣉࢩࢫࢸ࣒ࢆᐇࡋ㸪ȕ ∧ࡋ࡚ 2014 ᖺ 9 ᭶ࡽヨ⏝ࢆ㛤ጞࡋࡓ㸬ᐇࡉࢀࡓᶵ⬟ࡢ࠺ࡕ࡞ࡶࡢࡋ࡚ࡣ㸪 ࢱࢢࡼࡿࣇࣝ⟶ ⌮ᶵ⬟㸪 ྛ✀ࣇࣝ㸦⏬ീࣇࣝཬࡧ Word/Excel/PowerPoint/PDF 㸧ࢆ୍ᣓ⟶⌮ࡍࡿ ᶵ⬟㸪 ┤ឤⓗ࡞᧯సࡼࡿࢱࢢ᳨⣴ᶵ⬟㸪 ⨨ሗࡢ⣣ࡅᶵ⬟࡞ࡀ࠶ࡿ㸬 ᆅ㉁Ꮫ◊✲ᐊࡢ㛵ಀ⪅ࡽ㸴ྡࢆᑐ㇟ࡋ࡚㸪ࡇࡢࣉࣟࢺࢱࣉࢩࢫࢸ࣒ࢆヨ⏝ࡋ࡚ࡶࡽ ࡗࡓ⤖ᯝ㸪㞟ࡉࢀࡓࢹ࣮ࢱ⥲ᩘࡣ 892 ಶ࡞ࡗࡓ㸬࠺ࡕ⏬ീࡀ 630 ಶ࡛࠶ࡾ㸪ࡑࡢ docx/xlsx ➼ࡢࣇࣝࡀ 262 ಶ࡛࠶ࡗࡓ㸬ࡲࡓసᡂࡉࢀࡓ࣮࣌ࢪᩘࡣ 95 ࡞ࡾ㸯࣮࣌ࢪ࠶ ࡓࡾࡢᖹᆒࢹ࣮ࢱᩘࡣ 9.4 ࡞ࡗࡓ㸬୍᪉ࢱࢢ㛵ࡋ࡚ࡣ㸪⥲ᩘࡀ 138 ✀㢮࡞ࡾ㸪࡞ࡾ ࡢ㔜」ࡀぢࡽࢀࡓ㸬⏝㢖ᗘࡢ್᭱ࡣ 90 ᅇ࡛㸪10 ᅇ௨ୖ⏝ࡉࢀࡓࢱࢢࡣ 18 ✀࡛࠶ࡗ ࡓ㸬㏫ 3 ᅇ௨ୗࡢ⏝㢖ᗘࡢࢱࢢࡣ 13 ✀࡛࠶ࡗࡓ㸬 ⏝⪅ࡽࡢせᮃࡋ࡚ࡣ㸪ࢱࢢࡢ⾲グࡢᦂࢀᑐฎࡋ࡚ࡋ࠸㸪ࢱࢢධຊࡢ㝿⿵ᶵ ⬟ࡀ࠶ࡿࡼ࠸㸪⤒⦋ᗘࡽᆅྡࢱࢢࢆ⮬ື࡛ࡘࡅࡽࢀ࡞࠸㸪࠸ࡗࡓࢱࢢධຊ㛵ࡍࡿ ࡶࡢࡀከࡃᣲࡆࡽࢀࡓ㸬ࡇࢀࡣᚋࡢᨵၿ㡯┠ࡋ᳨࡚ウࡋ㸪㡰ᶵ⬟㏣ຍ࣭ᨵⰋࢆ⾜ࡗ࡚ ࠸ࡃணᐃ࡛࠶ࡿ㸬 - 26 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 2-04 ⅆᒣᄇⅆྐሗࢹ࣮ࢱ࣮࣋ࢫࡢ 2 ḟ⏝ࡘ࠸࡚ 㭯⏣┤அ㸦⚟ᒸ࣭ᕤ㸧࣭㧗ᶫఙᘺ㸦⚟ᒸ࣭ᕤ㸧࣭ ዟᮧ 㸦⚟ᒸ࣭⥲ྜሗฎ⌮ࢭࣥࢱ࣮㸧 About secondary use of eruptive history and informatics database N. Tsuruta (Fac. Eng., Fukuoka Univ.), S. Takahashi (Fac. Eng., Fukuoka Univ.), M. Okumura (Info. Tech. Center, Fukuoka Univ.) ᮏ✏࡛ࡣ㸪ⅆᒣᆅ㉁ࢹ࣮ࢱ࣮࣋ࢫಖᏑࡉࢀࡓࢹ࣮ࢱࡢά⏝᪉ἲࡘ࠸࡚⪃࠼ࡿ㸬◊✲⪅ ࡀ⮬㌟࡛㞟ࡵ࡚ࢹ࣮ࢱ࣮࣋ࢫಖᏑࡋࡓࢹ࣮ࢱࢆ 1 ḟࢹ࣮ࢱࡪࡇࡋ࡚㸪1 ḟࢹ࣮ࢱ ࢆ᳨⣴ࡋ࡞ࡀࡽㄽᩥࢆ᭩ࡃ࠸ࡗࡓ⏝ᙧែࢆࢹ࣮ࢱࡢ 1 ḟ⏝ࡪࡇࡍࡿ㸬୍᪉㸪 ◊✲ᶵ㛵ࡀබ㛤ࡉࢀ࡚࠸ࡿࢹ࣮ࢱࢆ㔞㞟ࡵ㸦࠼ࡤ⤫ィⓗ࡞㸧ฎ⌮ࢆࡋ࡚ᚓࡓࢹ࣮ࢱ ࢆ 2 ḟࢹ࣮ࢱࡪࡇࡋ࡚ 2 ḟࢹ࣮ࢱࢆⓑ᭩ࡢ୍㒊ࡋ࡚⏝ࡍࡿゝࡗࡓ⏝ᙧែࢆ 2 ḟ⏝ࡪࡇࡍࡿ㸬1 ḟ⏝ 2 ḟ⏝ࡢ㛵ಀࡣ㸪㠀බ㛤ࢹ࣮ࢱࡢ⏝බ㛤ࢹ࣮ࢱ ࡢ⏝ࡢ㛵ಀࡣᚲࡎࡋࡶᑐᛂࡋ࡞࠸㸬࠼ࡤᑗ᮶ⓗࡣ㸪◊✲┠ⓗ㝈ࡗ࡚◊✲⪅ಶேࡢ 㞟ࢹ࣮ࢱࢆᗈࡃබ㛤ࡍࡿࡇࡶ࠶ࡿ࡛࠶ࢁ࠺ࡋ㸪ඖࢹ࣮ࢱࢆබ㛤ࡋ࡞࠸ࡇࢆ๓ᥦ⤫ィ ฎ⌮ࡢά⏝ࢆㄆࡵࡿࡼ࠺࡞ᙧែࡶ⪃࠼ࡽࢀࡿ㸬ᅗ㸯 1 ḟ⏝ 2 ḟ⏝࠾ࡼࡧࢹ࣮ࢱࡢ බ㛤㠀බ㛤ࡢ㛵ಀ࠾࠸࡚ ⌧ᆅ ᚲせ࡞ࡿ࡛࠶ࢁ࠺せ⣲ᢏ⾡ ほ ࡘ࠸࡚ᩚ⌮ࡋࡓ㸬ࢹ࣮ࢱࡣ㸪ཧ⪃ 䠍ḟ⏝ ᡂᯝ≀ 䐟 or䐠 䠍ḟ䝕䞊䝍 㠀බ㛤 බ㛤 䐠 䠍ḟ⏝ ᡂᯝ≀ 䐡 䐢 䐣 䐠 䐤 䠎ḟ⏝ ᡂᯝ≀ 䐡䚸䐢䚸䐣 䠎ḟ䝕䞊䝍 㠀බ㛤 බ㛤 ᩥ⊩࡞ྠࡌࡼ࠺࢜ࣜࢪࢼ ࣝࡀ≉ᐃ࡛ࡁ࡞ࡅࢀࡤ࡞ࡽ࡞࠸㸬 ࡋࡓࡀࡗ࡚㸪ఱࡽࡢ ID ࢆຍ ࡍࡿࡇ࡞ࡿ㸬ࢹ࣮ࢱࡢಖᏑ 䐡䚸䐢䚸䐣 䠎ḟ⏝ ᡂᯝ≀ 䐟ಶே䛾PC䛷⟶⌮䛧䝃䞊䝞䛻䛿㍕䛫䛺䛔 䐠䝃䞊䝞ୖ䛷䠈⏝ᶒ㝈䛾ไ㝈䜔ㄆドᶵ⬟䜢⏝䛩䜛 䐡ᘬ⏝䛾㝿䛻ඖ䝕䞊䝍䜢୍ព䛻㎺䜜䜛䜘䛖䛺ID䜢䛩䜛 䐢᭱᪂ሗ䛜≉ᐃ䛷䛝䜛䜘䛖䛻䝕䞊䝍సᡂ᪥䜢䝇䝍䞁䝥䛩䜛 䐣䜰䜽䝉䝇䝻䜾䜢ṧ䛩 䐤ඖ䝕䞊䝍䛾㏫ᘬ䛝䜢チ䛥䛺䛔䛯䜑䛻䚸䝕䞊䝍ID䜢༏ྡ䛧䛶䛚䛟 ᅗ㸯㸬ࢹ࣮ࢱඹ᭷ᚲせ࡞せ⣲ᢏ⾡ - 27 - ࢧ࣮ࣂࢹࣞࢡࢺࣜ㸪ࣇ ࣝ ྡ ࢆ ࡗ ࡓ URI 㸦 Uniform Resource Identifier㸧࡞ࡀᛂ⏝࡛ ࡁࢀࡤຠ⋡ࡀⰋ࠸㸬୍᪉࡛㸪㠀බ 㛤ࡢ㸯ḟࢹ࣮ࢱࡽ㸰ḟࢹ࣮ࢱ ࢆ⏕ᡂࡍࡿ㝿ࡣ㸪㸰ḟࢹ࣮ࢱࡢ ⏕ᡂసᴗ୰㠀බ㛤ࢹ࣮ࢱࢆ㎺ ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡿࡇࡀ࡛ࡁ࡞࠸ࡼ࠺ࡍࡿᚲせࡀ࠶ࡿ㸬ࡇࢀࡣ㸪ID ࡢ༏ྡࡢᢏ⾡ࡀᚲせ࡞ࡿ㸬༏ྡ ࡣಶேሗࢆ㸰ḟ⏝ࡍࡿ㝿࡞ࡶࢃࢀ࡚࠸ࡿᢏ⾡࡛࠶ࡿ㸬ࡲࡓ㸪㟢㢌⏬ീࢆ⦋ᗘ ⤒ᗘ᳨࡛⣴ࡍࡿ㸪ᙳᮇࡢ␗࡞ࡿ」ᩘࡢ⏬ീࡀᚓࡽࢀࡿࡇࡀ⪃࠼ࡽࢀࡿ㸬ࡇࡢሙྜ㸪 ࡕࡽࡀ᭱᪂ࡢሗ࡛࠶ࡿࡣ㔜せ࡞ࡢ࡛ᙳࡢࢱ࣒ࢫࢱࣥࣉࢆࢹ࣮ࢱࡋ࡚࠾ࡃ ࡇࡀᚲせ࡞ࡿ㸬᭦ࡣ㸪ṇ⏝ࡢᢚṆຠᯝࢆാࡏࡿព࡛㸪ࢹ࣮ࢱࡢࢡࢭࢫࣟ ࢢࢆ୍ᐃᮇ㛫ಖᣢࡍࡿࡇࡶᚲせ࡞ࢁ࠺㸬 ḟ㸪⏬ീฎ⌮ࢆ⏝࠸ࡓ 2 ḟ⏝ࢆど㔝ධࢀࡓᢏ⾡㛤Ⓨࡢලయࢆ♧ࡍ㸬ࡇࡢᢏ⾡ࡣ ࡘࡢせ⣲ࡽ࡞ࡿ㸬୍ࡘ┠ࡣ㸪2 ḟ⏝ࢆᐜ᫆ࡍࡿࡓࡵࡢ 2 ḟࢹ࣮ࢱࡢ⏕ᡂᢏ⾡࡛࠶ࡿ㸬 ࡘ┠ࡣ㸪2 ḟ⏝ࡢලయⓗ࡞ࣉࣜࢣ࣮ࢩࣙࣥᢏ⾡࡛࠶ࡿ㸬୍ࡘ┠ࡢせ⣲㸦ᮏ⏣࣭➉ୗ࣭๓⏣࣭ 㭯⏣ 2014㸧࡛ࡣ㸪㟢㢌┿ࡀ㔞㞟ࡲࡿࡇࢆᐃࡋ࡚㸪ࢧ࣮ࣂୖ࡛㟢㢌┿ࡽ᩿ᒙ ࡢೃ⿵࡞ࡿடࢆ⮬ື᳨ฟࡋ㸪ࡑࡢ 3 ḟඖⓗ࡞ጼໃࢆ᥎ᐃࡍࡿࡇࢆ┠ⓗࡋ࡚࠸ࡿ㸦ࢱ ࣈࣞࢵࢺ➃ᮎ࡞ᐇࡍࢀࡤ㟢㢌ࡢᙳ⌧ᆅ࡛ィ ࢆ῭ࡲࡏ㸪ィ ⤖ᯝࢆࢧ࣮ࣂ ࢵࣉ࣮ࣟࢻࡍࡿࣥࢱ࣮ࣇ࢙ࢫ࣭ࢶ࣮ࣝࡋ࡚ࡶ⏝࡛ࡁࡿ㸧 㸬ᅗ㸰♧ࡍࡼ࠺㸪ᆅ☢Ẽ ࢭࣥࢧ࣮ຍ㏿ᗘࢭࣥࢧ࣮ࢆෆⶶࡋࡓࢫ࣐࣮ࢺࣇ࢛ࣥ࡞ࡢ࣓࡛࢝ࣛ㟢㢌ࢆື⏬ᙳࡍࡿ 㸦a㸧㸬ᙳ୰࣓࢝ࣛࢆ⛣ືࡋ㸪ࢫࢸࣞ࢜ࣅࢪࣙࣥࡼࡾ≉ᚩⅬࡢ୕ḟඖ⨨ࢆ࣓࢝ࣛ୰ᚰ ᗙᶆ⣔࡛ィ ࡍࡿ㸦b㹼d㸧㸬ࡑࡢ㝿ࢭࣥࢧ࣮ࡽᚓࡽࢀࡓሗࢆࡶ࣓࢝ࣛࡢ⨨ጼໃࢆᆶ ┤㍈⦋ᗘ⤒ᗘࡽ࡞ࡿỈᖹ㍈ࡼࡗ࡚ᵓᡂࡉࢀࡿᗙᶆ⣔㸦ࡇࢀࢆᮏ◊✲࡛ࡣᆅ⌫ᗙᶆ⣔ ࢇ࡛࠸ࡿ㸧࡛᥎ᐃࡋ࡚࠾ࡁ㸪≉ᚩⅬࡢ୕ḟඖᗙᶆ್ࢆᆅ⌫ᗙᶆ⣔ኚࡍࡿ㸬᭦㟢㢌⏬ ീࡽட⥺ࢆ⏬ീ≉ᚩࡋ࡚ᢳฟࡋ㸪ඛࡢ≉ᚩⅬࢆட⥺ୖ࠶ࡿ࠸ࡣࡑࡢ࿘ᅖ㤳ࡢ≉ᚩ Ⅼ㝈ᐃࡍࡿ㸦e㸧㸬㝈ᐃࡋࡓ≉ᚩⅬࡢᗙᶆ್ࡽ㸪டࡢ᪉ྥࢆ᭱ᑠ᥎ᐃࡼࡾ᥎ᐃࡍ ࡿ㸦f㸧㸬 ࡘ┠ࡢせ⣲㸦๓⏣࣭ᡭ࣭㭯⏣ 2014㸧࡛ࡣ㸪ࢪ࢜ࣃ࣮ࢡࡸ㟢㢌ࡢ⌧ሙ࠾࠸࡚㸪AR 㸦Augmented Reality: ᣑᙇ⌧ᐇឤ㸧ᢏ⾡ࢆ㛤Ⓨࡋ࡚㸪2 ḟࢹ࣮ࢱࢆᐇ㝿ࡢࢩ࣮ࣥᢞᙳࡍࡿࡇ ࡼࡗ୍࡚⯡ᕷẸྥࡅࡢᏛ⩦ᩍᮦࡋࡓࡾ㸪㟢㢌ࡢㄪᰝࢆᐜ᫆ࡋࡓࡾࡍࡿࡇࢆ┠ⓗ ࡋ࡚࠸ࡿ㸬≉Ṧ࡞࣐࣮࣮࢝ࢆᚲせࡏࡎ㸪๓ࡢ㢼ᬒࡑࡢࡶࡢࢆ࣐࣮࣮࢝ࡋ࡚⏝ࡍࡿ ࣐࣮࣮࢝ࣞࢫ᪉ᘧࡢ୍ࡘ PTAMM(Parallel Tracking And Multiple Mapping, G. Klein࣭D.W. Murray 2007)ࢆ᥇⏝ࡋ࡚࠸ࡿ㸬PTAMM ࡛ࡣ㸪๓㏙ࡢட᳨ฟྠࡌࢫࢸࣞ࢜どࡢཎ⌮ࢆ⏝࠸ ࡚㸪ࢩ࣮ࣥ୰ࡢ≉ᚩⅬࡢ 3 ḟඖ⨨ࢆ᥎ᐃࡋ࡚࣐࣮࣮࢝ࡢ௦ࢃࡾࡋ࡚グ᠈ࡍࡿ㸬ࡇࡢグ᠈ ࢹ࣮ࢱࢆ࣐ࢵࣉࡪ㸬ࡑࡢᚋࡣ㸪⌧ᅾࡢࢩ࣮ࣥࡽᚓࡽࢀࡿ≉ᚩⅬࡢ 3 ḟඖ⨨࣐ࢵࣉ ࡢ≉ᚩⅬࡢ 3 ḟඖ⨨ࢆ↷ྜࡋ࡚⌧ᅾࡢ࣓࢝ࣛࡢ⨨࣭ጼໃࢆ᥎ᐃࡋ㸪┠ⓗࡢ⨨㹁㹅 ࢆ⾲♧ࡍࡿ㸬ᅗ㸱ᅗ㸰࡛ᚓࡓடୖࡢ≉ᚩⅬࢆ㟢㢌ࢩ࣮ࣥ㹁㹅ࡋ࡚㔜ࡡྜࢃࡏ⾲♧ࡋ ࡓࢆ♧ࡍ㸬どⅬࢆኚ࠼࡚ࡶடࡢ⨨ࡀ≉ᐃ࡛ࡁ࡚࠸ࡿᵝᏊࡀࢃࡿ㸬CG ࡍࡿࢥࣥࢸࣥ ࢶࡋ࡚ࡣ㸪ㄝ᫂⏝ࡢ௬ࣃࢿࣝࡸ࣒࣮ࣅ࣮ࢆ㔜ࡡ⾲♧ࡍࡿࡇ࡞ࡀ⪃࠼ࡽࢀࡿ㸬 - 28 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 㸦a㸧ᴫᛕᅗ 㸦b㸧㟢㢌ぢ❧࡚ࡓࣃࢿࣝ 㸦c㸧⏬ീฎ⌮ࡼࡿ≉ᚩⅬ᳨ฟ (e)ட᳨ฟ⤖ᯝ≉ᚩⅬࡢ㑅ᢥ (d)≉ᚩⅬࡢ୕ḟඖィ ⤖ᯝ (f)ட᪉ྥࡢ୕ḟඖィ ⤖ᯝ ᅗ㸰㸬ட⥺ࡢ㸱ḟඖ ᐃࡢฎ⌮㐣⛬ - 29 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ᅗ㸱㸬PTAMM ࡼࡿ AR ࡢᐇ⌧ ࠝཧ⪃ᩥ⊩ࠞ G. Klein and D.W. Murray(2007): Parallel Tracking and Mapping for Small AR Workspaces, Proc International Symposium on Mixed and Augmented Reality (ISMAR) 2007, http://www.robots.ox.ac.uk/ActiveVision/Publications/klein_murray_ismar2007/klein_murray_is mar2007.html ᮏ⏣⿱⣖࣭➉ୗඃ࣭๓⏣బᚿ࣭㭯⏣ ┤அ㸦2014㸧 㸸ᆅ㉁ㄪᰝࡢࡓࡵࡢ㟢㢌⏬ീ࠾ࡅࡿட ᢳฟ㛵ࡍࡿ◊✲㸪ಙᏛᢏሗ, vol. 113, no. 431, PRMU2013-125, pp. 25-30㸬 ๓⏣బᚿ࣭ᡭ⩧࣭㭯⏣┤அ㸦2014㸧 㸸≉ᚩⅬᢳฟᡓ␎ࡢᨵⰋࡼࡿ⮬↛⎔ቃࢆᑐ㇟ࡋ ࡓ PTAMM ࡢ⨨᥎ᐃ⬟ຊࡢྥୖ㸪ಙᏛᢏሗ, vol. 113, no. 431, PRMU2013-134, pp. 73-76㸬 - 30 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-01 ༡ᕞ㸪ụ⏣࢝ࣝࢹࣛࡢᄇⅆྐ ✄ᐶோ㸦す᪥ᮏᢏ⾡㛤Ⓨ㸧࣭ᡂᑿⱥோ㸦Ṋᒸྎ㧗㸧 ዟ㔝 㸦⚟ᒸ㸧࣭ᑠᯘဴኵ㸦㮵ඣᓥ㸧 Eruptive history of Ikeda caldera, southern Kyushu, Japan H. Inakura (WEST JEC), H. Naruo (Takeokadai High School) M. Okuno (Fukuoka Univ.) and T. Kobayashi (Kagoshima Univ.) Ikeda caldera is a small-scale caldera (about 4 km in diameter), located in the southern tip of the Satsuma Peninsula, southern Kyushu, Japan. We made a detailed geological study to understand the eruptive history of Ikeda caldera (Fig. 1), including a study of the processes leading to the catastrophic eruption. The pre-caldera activity began at about 20 cal kBP with the Iwamoto ash fall deposit. The Senta lava was also effused before the Kikai-Akahoya tephra (7.3 cal kBP). The caldera-forming eruption began at 6.4 cal kBP with a phreatic explosion that produced the Ikezaki ash fall and surge deposits. This was soon followed by the magmatic eruptions that produced the Osagari and Mizusako scoria fall deposits and the Ikeda pumice fall deposit. During the climactic stage, the Ikeda ignimbrite was erupted and covered portions of the coastal area. Immediately after the caldera-forming event, four maars were formed along the fissure vent southeast of the caldera. The Yamagawa maar, which is the largest and is located at the southeastern end of the fissure vent, erupted a pumiceous base surge (the Yamagawa base surge), while the other maars ejected small amounts of accessory or accidental materials. During the late stage of the Ikeda eruption, a phreatomagmatic eruption occurred at the bottom of the caldera floor, which formed the widespread Ikedako ash fall deposit. The central lava dome was formed during the late stage of this eruption. After the Ikedako ash fall, secondary explosions of the Ikeda ignimbrite occurred mainly along the coastal area, generating small base surge deposits. ụ⏣࢝ࣝࢹࣛࡣ༡ᕞ㸪⸃ᦶ༙ᓥ༡➃⨨ࡍࡿᑠᆺ㸦┤ᚄ⣙ 4 km㸧ࡢ࢝ࣝࢹ࡛ࣛ࠶ࡿ㸬 ࢝ࣝࢹࣛᙧᡂᄇⅆࡣࡑࡢつᶍࡢࡁࡉࡽᄇⅆ๓ࡢሗࡀࢇኻࢃࢀ࡚ࡋࡲ࠺ࡀ㸪ᑠᆺ ࡢụ⏣࢝ࣝࢹࣛࡣ㸪ᄇⅆ๓ࡢሗࡀẚ㍑ⓗಖᏑࡉࢀ࡚࠸ࡿ࢝ࣝࢹ࡛ࣛ࠶ࡿ㸬ᮏⓎ⾲࡛ࡣ㸪ヲ ⣽࡞ᆅ㉁ㄪᰝࢆࡶ㸪࢝ࣝࢹࣛᙧᡂᄇⅆࡢ‽ഛ㐣⛬ࢆྵࡵࡓụ⏣࢝ࣝࢹࣛࡢᄇⅆྐࢆ♧ࡍ㸬 ụ⏣࢝ࣝࢹࣛࡢάືඛ⾜ࡍࡿ⣙ 2 ᖺ๓ᒾᮏ㝆ୗⅆᒣ⅊ሁ✚≀ࢆᄇฟࡋࡓ㸬⏣⁐ᒾ ࡶ㨣⏺࢝ࣝࢹࣛ㸦7.3 cal kBP㸧ࡢάືࡢ๓ᄇฟࡋ࡚࠸ࡿ㸬6.4 cal kBP ࡢ࢝ࣝࢹࣛᙧᡂᄇⅆ - 31 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 㸦Fig. 1㸧ࡣ㸪ỈẼ⇿Ⓨࡼࡾụᓮࢧ࣮ࢪሁ✚≀࣭㝆ୗⅆᒣ⅊ሁ✚≀ࡢᄇฟࡼࡾ㛤ጞࡋ㸪 ࡑࡢᚋ࣐ࢢ࣐ᄇⅆ㸦୍㒊࣐ࢢ࣐ỈẼᄇⅆࡶྵࡴ㸧⛣⾜ࡋ㸪ᑿୗ㝆ୗࢫࢥࣜሁ✚≀㸪Ỉ ㏕㝆ୗࢫࢥࣜሁ✚≀ཬࡧụ⏣㝆ୗ㍍▼ሁ✚≀ࢆ┦ḟ࠸࡛ᄇฟࡋࡓ㸬᭱┒ᮇࡣụ⏣ⅆ○ὶ ሁ✚≀ࢆᄇฟࡋ㸪࢝ࣝࢹࣛࢆᙧᡂࡍࡿࡶ㸪ⅆ○ὶࡣᙜࡢෆ‴ࢆᇙࡵ❧࡚⌧ᅾࡢⅆ○ὶ ྎᆅࢆᙧᡂࡋࡓ㸬ࡇࡢ┤ᚋ㸪࢝ࣝࢹࣛࡢ༡す᪉ྥḟࠎ࣐࣮ࣝࢆᙧᡂࡋࡓ㸬ࡇࡢ࠺ࡕ⤥※ ࡽ᭱ࡶ㐲࠸ᒣᕝ࣐࣮࡛ࣝࡣ࣮࣋ࢫࢧ࣮ࢪ㸦ᒣᕝ࣮࣋ࢫࢧ࣮ࢪሁ✚≀㸧ࡀⓎ⏕ࡋࡓࡀ㸪ࡑࢀ ௨እࡢ࣐࣮࡛ࣝࡣ㸪ⅆཱྀ࿘㎶ᑡ㔞ࡢ␗㉁ᒾ∦ࡶࡋࡃࡣ㢮㉁ᒾ∦ࡢሁ✚ࡀㄆࡵࡽࢀࡿࡔࡅ࡛ ࠶ࡿ㸬 ୍㐃ࡢᄇⅆࡢ᭱ᚋࡣ㸪࢝ࣝࢹࣛᗏ࡛ỈẼ࣐ࢢ࣐ᄇⅆࡀⓎ⏕ࡋ㸪ụ⏣†㝆ୗⅆᒣ⅊ ሁ✚≀ࢆᄇฟࡋࡓ㸬ࡇࡢᄇⅆࡢᮎᮇࡣ⁐ᒾ㡬ୣࡀᙧᡂࡉࢀࡓ㸬ụ⏣†ⅆᒣ⅊ሁ✚ᚋࡣ㸪 ἢᓊ㒊࡛ࡣụ⏣ⅆ○ὶሁ✚≀ࡢḟ⇿ⓎࡀⓎ⏕ࡋࡓ㸬ࡇࢀࡽࡢᄇⅆࡽᩘ༓ᖺᚋࡧ࢝ࣝ ࢹࣛ༡⦕ࡢ㘠ᓥᓅࡢάືࡀ㛤ጞࡋ㸪ⅆ○≀࣭⁐ᒾࢆᄇฟࡋࡓ㸬 Fig. 1 Type columnar section of Ikeda caldera products (after, Inakura et al., 2014). 3-02 ጸⰋධᡞⅆ○ὶᄇฟ⮳ࡿ๓㥑ᄇⅆ㐣⛬㸸࣐ࢢ࣐⁀ࡲࡾࡢῶᅽ㐍⾜ - 32 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ୗྖ ಙኵ㸦⏘⥲◊࣭ά᩿ᒙⅆᒣ㸧 Precursory eruptive process for the Ito ignimbrite eruption of Aira caldera: Decompression process of the magma chamber N. Geshi (Inst. Earthquake Volcano Geology, AIST) 㝗ἐ࢝ࣝࢹࣛࡢᙧᡂࡣ㸪࣐ࢢ࣐⁀ࡲࡾࡽࡢᛴ㏿࡞࣐ࢢ࣐ࡢᄇฟࡼࡗ࡚㸪࣐ࢢ࣐⁀ࡲࡾ ෆࡢ࣐ࢢ࣐ᅽࡀపୗࡋ㸪ᨭᣢࢆኻࡗࡓ࣐ࢢ࣐⁀ࡲࡾኳࡀ࣐ࢢ࣐⁀ࡲࡾෆỿ㝆ࡍࡿࡇ ࡼࡗ࡚ᘬࡁ㉳ࡇࡉࢀࡿ㸬࣐ࢢ࣐⁀ࡲࡾኳࡢỿ㝆ࡣ㸪⎔≧᩿ᒙࡢᙧᡂࡑࡢኚࡼࡗ࡚つ ไࡉࢀࡿ㸬ࡋࡓࡀࡗ࡚㸪㝗ἐ࢝ࣝࢹࣛࡢᙧᡂ࣓࢝ࢽࢬ࣒ࢆ⌮ゎࡍࡿࡓࡵࡣ㸪࣐ࢢ࣐⁀ࡲࡾ ࡢῶᅽ㐣⛬ࢆࢥࣥࢺ࣮ࣟࣝࡍࡿ“๓㥑ᄇⅆ”ࣉࣟࢭࢫࢆ⌮ゎࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸㸬 㮵ඣᓥ┴ࡢጸⰋ࢝ࣝࢹࣛࡽ⣙ 29,000 ᖺ๓Ⓨ⏕ࡋࡓጸⰋ AT ᄇⅆࡣ㸪ᡃࡀᅜ࠾࠸࡚ᚋ ᮇ᭦᪂ୡ㹼᪂ୡ㉳ࡇࡗࡓ᭱⣭ࡢᄇⅆࡢ୍ࡘ࡛࠶ࡿ㸬ࡇࡢᄇⅆࡼࡗ࡚ᄇฟࡋࡓධᡞⅆ ○ὶࡣ㸪ᕞᓥ༡㒊ࡢᗈ࠸⠊ᅖᗈࡀࡗࡓ㸬ࡑࡢ⥲㔞ࡣ 350 ❧᪉ km ᥎ ࡉࢀ࡚࠸ࡿ㸦ୖ 㔝㸪2001㸧 㸬ධᡞⅆ○ὶࡢᄇฟඛ⾜ࡋ㸪⌧ᅾࡢᱜᓥ㏆࠶ࡓࡿጸⰋ࢝ࣝࢹࣛ༡⦕㒊ࡽ つᶍ࡞ࣉࣜࢽ࣮ᘧᄇⅆࡀⓎ⏕ࡋ㸪⣙ 100 ❧᪉ km ࠾ࡼࡪ㝮㝆ୗ㍍▼ࢆᄇฟࡋࡓ 㸦Kobayashi et al. 1983㸧 㸬ࡇࡢ㝮㍍▼ࡢᄇฟࡣጔᒇⅆ○ὶࡢᄇฟ⛣⾜ࡋ㸪ḟ࠸࡛࢝ࣝࢹ ࣛ㝗ἐࡢ㛤ጞࢆ♧ࡍ⪃࠼ࡽࢀࡿடᆏゅ♟ᒙࡢᙧᡂࡑࢀࢆそ࠺ධᡞⅆ○ὶࡢᄇฟ⮳ࡗ ࡓ㸬ᚑࡗ࡚㸪ጸⰋ AT ᄇⅆ࠾ࡅࡿ࢝ࣝࢹࣛ㝗ἐࡣ㸪㝮㝆ୗ㍍▼ࡢᄇฟࢫࢸ࣮ࢪ࠾ࡅࡿ ࣐ࢢ࣐ࡢฟࡑࢀࡼࡿ࣐ࢢ࣐⁀ࡲࡾࡢῶᅽࡼࡗ࡚ᘬࡁ㉳ࡇࡉࢀࡓ⪃࠼ࡽࢀࡿ㸬 㝮㝆ୗ㍍▼ࡢᄇฟ㐣⛬ࢆ᳨ウࡍࡿࡓࡵ㸪ࡑࡢᒙᗎཬࡧᵓᡂ≀ࡢᆶ┤ኚࢆゎᯒࡋ࡚࠸ ࡿ㸬㝮㝆ୗ㍍▼ሁ✚≀ࡣ┠❧ࡗࡓ㝆ୗࣘࢽࢵࢺࡣ(୍㒊ࡢࡸࡸ⣽⢏ࡢⷧᒙࢆ㝖࠸࡚)ㄆࡵ ࡽࢀࡎ㸪యࡋ࡚ୖ᪉⢒⢏ࡍࡿࡰ༢୍ࡢ㝆ୗࣘࢽࢵࢺࢆᵓᡂࡍࡿ㸦ᅗ 1㸧㸬ヲࡋࡃ ぢࡿ㸪ᅗ 1 ࡢᆅⅬ㸦ศᕸ㍈ୖ㸪ᱜᓥࡽ⣙ 15km㸧࡛ࡣᇶᗏࡽ⣙ 1m ࡢ㡿ᇦ࡛ࡣ㸪ࡑ ࢀࡼࡾୖ㒊ẚࡿ㍍▼⢏ᚄࡀᑠࡉࡃ㸪ୖ᪉ྥࡗ࡚ᛴ㏿᭱⢏ᚄࡀቑຍࡍࡿ㸬ᇶᗏ ࡽ 1m ࡼࡾୖ࡛ࡣ㸪⣙ 4m ㏆ཌࡉ 0.2m ࡢࡸࡸ⣽⢏ࡢᒙࢆᣳࡴࡶࡢࡢ㸪యࡋ࡚⦆ ࡸ᭱⢏ᚄࡀቑຍࡍࡿ㸬ࡇࡢࡼ࠺࡞᭱⢏ᚄࡢୖ᪉⢒⢏ࡣ㸪㝮㝆ୗ㍍▼ศᕸᇦࡢ ࡰᇦ࡛ほᐹࡉࢀࡿ㸦Kobayashi et al., 1983㸧 㸬㝆ୗ㍍▼ࡢ᭱⢏ᚄࡣᄇ↮㧗ᗘ౫Ꮡࡋ㸪ᄇ ↮㧗ᗘࡣᄇฟ⋡ࡢ 1/4 ẚࡍࡿ㸦ref㸧ࡓࡵ㸪㝮㝆ୗ㍍▼యࡳࡽࢀࡿୖ᪉⢒⢏ ࡣ㸪㝮㍍▼ࡢᄇฟ⋡ࡀᄇⅆࡢ㐍⾜ࡘࢀ࡚ቑຍࡋࡓࡇࢆ♧ࡋ࡚࠸ࡿ㸬 ୍᪉㸪㝮㝆ୗ㍍▼ྵࡲࢀࡿ␗㉁ᒾ∦ࡣⅆ㐨ࡢᣑ㐣⛬ࢆᫎࡋ࡚࠸ࡿ㸬㝮㝆ୗ㍍▼ - 33 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ྵࡲࢀࡿ␗㉁ᒾ∦ࡣ㸪ᆅ⾲㏆Ꮡᅾࡋ࡚࠸ࡓ⪃࠼ࡽࢀࡿᏳᒣᒾ㹼ࢹࢧࢺ⁐ᒾ ∦㸪ጸⰋ࢝ࣝࢹࣛࡢᇶ┙ࢆᵓᡂࡍࡿᅄ༑ᒙ⩌ࡽࡶࡓࡽࡉࢀࡓ㡫ᒾཬࡧ⣽⢏ࡢ◁ᒾࡽ ࡞ࡿ㸬␗㉁ᒾ∦ࡢྵ᭷㔞ࡣ㸪㝮㝆ୗ㍍▼ࡢయࢆ㏻ࡋ࡚⣙ 4㹼5㸣⛬ᗘ࡛࠶ࡿ㸬ᚑࡗ࡚㸪 㝮㝆ୗ㍍▼ࡢᄇฟ୰㸪⣙ 5 ❧᪉ km ࡢᇶ┙ᒾ࠾ࡼࡧᆅ⾲㏆ࡢⅆᒣᒾ㢮ࡀ◚○ࡋ␗㉁ᒾ ∦ࡋ࡚ᄇฟࡋࡓࡇࢆ♧ࡋ࡚࠸ࡿ㸬 㝮㝆ୗ㍍▼࡛ࡣ㸪ⅆ㐨ቨࡢつᶍ࡞㣗ࡑࢀࡼࡿⅆ㐨ᚄࡢᣑࡼࡾ㸪㧗࠸ᄇฟ⋡ ࢆ⥔ᣢࡋ⥆ࡅࡿࡇࡀྍ⬟࡞ࡗࡓ᥎ ࡉࢀࡿ㸬ጸⰋ࢝ࣝࢹࣛࡽⓎ⏕ࡋࡓࡢ㍍▼ᄇ ⅆ࡛ࡣ㸪␗㉁ᒾ∦ࡢྵ᭷㔞ࡣ㝮㝆ୗ㍍▼ẚ࡚ᑠࡉࡃ㸪ᇶ┙ᒾࡢつᶍ࡞㣗ࡣㄆࡵࡽ ࢀ࡞࠸㸬ࡇࡢࡇࡽ㸪࢝ࣝࢹࣛ㝗ἐ⮳ࡿ༑ศ࡞࣐ࢢ࣐⁀ࡲࡾࡢῶᅽࢆࡶࡓࡽࡍつᶍ࡞ ࣐ࢢ࣐ᄇฟࡣ㸪ⅆ㐨ࡢᣑࣉࣟࢭࢫࡼࡗ࡚ࢥࣥࢺ࣮ࣟࣝࡉࢀ࡚࠸ࡿࡇࢆ♧၀ࡍࡿ㸬 10 Height from the bottom of Osumi Pumice deposit (m) Ito pyfl 8 6 ML MP 4 Osumi pumice fall dep. 2 0 0 2 4 6 8 Diameter (cm) ᅗ 1 㝮㝆ୗ㍍▼ሁ✚≀ࡢ᭱㍍▼⢏ᚄ㸦MP㸧ཬࡧ▼㉁ᒾ∦㸦MP㸧ศ ᕸ㸬ᱜᓥࡽ༡ᮾ⣙ 15km ࡢᆶỈᕷᆶᱜ㸬 ᘬ⏝ᩥ⊩ Kobayashi T., Hayakawa Y., Aramaki S., (1983) Thickness and grain-size distribution of the Osumi pumice fall deposit from the Aira caldera. Bull Volcanol Soc Japan, 28, 129-139. ୖ㔝㱟அ(2001)ⅆᒣ⅊⢏Ꮚ⤌ᡂࡢഃ᪉࣭ᆶ┤ኚࡽぢࡓධᡞⅆ○ὶࡢሁ✚ᶵᵓ㸬ⅆᒣ㸪46, 257-268㸬 3-03 㝗ἐ࢝ࣝࢹࣛࡢᄇฟ㔞࣐ࢢ࣐⁀ࡾࡢ‽ഛᮇ㛫 - 34 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ୕ᾆ ຓ㸦㟁ຊ୰ኸ◊✲ᡤ㸧 The volume and periodicity of magma discharge at the caldera-forming eruption: A review D. Miura (CRIEPI) ࢝ࣝࢹࣛࡑࡢ㝗ἐᵓ㐀ࡣ㸪ᆅୗᏑᅾࡍࡿᕧ࣐ࢢ࣐⁀ࡾ㛵ಀࡀ῝࠸࠸ࢃࢀࡿ (e.g., Gayer and Martí, 2008; Sobradelo et al., 2010)㸬ᕧᄇⅆ࡛ᨺฟࡉࢀࡿ࣐ࢢ࣐ࡢᄇฟ㔞ࡣ㸪࢝ࣝࢹ ࣛࡢ┤ᚄ (Sc) ࡸ㠃✚ (A) ᑐࡋ࡚㸪୧ᑐᩘ㍈ୖ࡛ṇࡢ┦㛵ࡀㄆࡵࡽࢀ࡚࠸ࡿ (e.g., Spera and Crisp, 1986; Sato and Taniguchi, 1997; Fig. 1)㸬┤ᚄ (Sc)࣭㠃✚ (A)ࡣᵓ㐀せ⣲ࡢ୍㒊࡛࠶ࡿࡀ㸪 ῝ࡉࢆྵࡵࡓ 3 ḟඖ㝗ἐᵓ㐀ࡀᄇฟ㔞࠼ࡿᙳ㡪ࡘ࠸࡚ࡣⰋࡃࢃࡗ࡚࠸࡞࠸㸬 ࢝ࣝࢹࣛᚄኚᙧ࣮ࣔࢻ㸸㝗ἐᗋࡢኚᙧ࣮ࣔࢻࡣⅆ㐨ࡢศᕸࢆᨭ㓄ࡍࡿࡓࡵ㸪ᄇฟ㔞࣭ᄇฟ ᵝᘧᙳ㡪ࡀࡁ࠸᥎ᐹࡉࢀࡿ㸬ᆅẆࡢ᩿㠃࠾࠸࡚㸪࢝ࣝࢹࣛࡢ┤ᚄ (Sc)࣐ࢢ࣐⁀ࡾ ኳࡢ῝ࡉ (D) ࡢẚࡣ Roof aspect ratio ᐃ⩏ࡉࢀ (RAR = D/Sc: Roche et al., 2000)㸪1 ᗘࡢ㝗 ἐక࠺ኚᙧ࣮ࣔࢻࡣ㸪RAR ࡼࡗ࡚ኚࡍࡿࡉࢀࡿ (e.g., Roche et al., 2000; Acocella et al., 2000)㸬㝗ἐᗋࡢኚᙧࢆ࡞࠺ᵓ㐀せ⣲ࢆᘬᙇࢀ┠ࡸ᩿ᒙ➼ࡢ㐃⥆㠃ࡳ࡞ࡋࡓሙྜ㸪 —ᑠつᶍ᩿ᒙࡢྜࢆ⾲ࡍ⣼✚㢖ᗘศᕸࡣࠕࡁ๎ࠖᚑ࠺ணࡉࢀࡿࡓࡵ㸪㈇ࡢഴࡁ ࢆ♧ࡍࡁᣦᩘࡀ㸪㝗ἐᗋࡢኚᙧ࣮ࣔࢻࢆ⾲ࡍ㸬㈇ࡢഴࡁࡀࡁ࠸㸪ᑠつᶍ᩿ᒙࡢᐤ ⋡ࡀ㧗ࡃ㸪᩿ᒙ⩌ࡢ⥲⾲㠃✚ࡀࡁ࠸ኚᙧ㸪ࡍ࡞ࢃࡕᘏᛶⓗኚᙧ࡞ࡿ㸬ྠࡌᚄࢧࢬ࡛ኚ ᙧࡀ␗࡞ࡿ࢝ࣝࢹࣛࢆẚ㍑ࡍࡿ㸪RAR ࡀࡁࡃ᩿ᒙ⾲㠃✚ࡀࡁ࠸ኚᙧ࣮ࣔࢻࢆ㉳ࡇࡍ࢝ ࣝࢹࣛᄇⅆࡣ㸪ኚᙧᑐࡍࡿෆ㒊 (⇕) ࢚ࢿࣝࢠ࣮ศ㓄ࡀࡁ࠸࠸࠼ࡿ㸬୍᪉㸪ᄇฟ≀ࡽ ෆ㒊࢚ࢿࣝࢠ࣮ࢆぢ✚ࡾ㸪ྠ࢚ࢿࣝࢠ࣮┦ᙜࡢ᰾⇿Ⓨẚ㍑ࡍࡿ㸪ᆺࡢ࢝ࣝࢹࣛࡑ ࡢᚄࡀ᭷ពࡁ࠸ (Scandone, 1990)㸬ࡇࡢࡇࡽ㸪ᆺࡢ࢝ࣝࢹ࡛ࣛࡣຠ⋡ⓗ࡞ኚᙧ࣮ࣔ - 35 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࢻࡀᚲせ᥎ ࡉࢀ㸪ὸ࠸࣐ࢢ࣐⁀ࡾࡢ᪉ࡀ᭷࡛࠶ࡿ⪃࠼ࡽࢀࡿ (୕ᾆ࣭⏣, 2007)㸬 ࣐ࢢ࣐౪⤥⣔ࡢ㐍㸸ᕧᄇⅆࡢ࿘ᮇᛶࢆ᥎ ࡍࡿࡓࡵࡣ㸪㔞ࡢ࣐ࢢ࣐ࢆᨺฟࡍࡿ࣐ࢢ ࣐⁀ࡾࡢ‽ഛ㐣⛬㸪ࡍ࡞ࢃࡕ㸪࣐ࢢ࣐౪⤥⣔ࡢ㐍ࡘ࠸࡚⪃ᐹࡀᚲせ࡛࠶ࡿ㸬୍⯡㸪 つᶍ࣐ࢢ࣐ᄇฟࡣఇṆᮇ㛫ࡀ㛗࠸ࡉࢀࡿࡀ (Spera and Crisp, 1986; White et al., 2006)㸪ࢹ࣮ ࢱ☜ᐇᛶࡀࡁࡃ㸪ࡲࡓ㸪ᕧᄇⅆࡢ࿘ᮇᛶࢆ୍⯡ࡍࡿᐇࡋ࡚࠸࡞࠸ (Deligne et al., 2010)㸬᪤άືࢆ⤊࠼ࡓ࢝ࣝࢹࣛⅆᒣ⩌࡛ࡣ㸪㝵ẁᅗ࠾࠸࡚ᕧᄇⅆࡢ࿘ᮇᛶࢆ㆟ㄽ ࡋࡓࡀ࠶ࡾ (Salisbury et al., 2011)㸪㝵ẁᅗࢆ≀⌮Ꮫⓗࣔࢹࣝࡍࡿࡇࡶ㔜せ࡛࠶ࡿ㸬 ᕧᄇⅆࡢఇṆᮇ㛫ࡣ୰࣭ᑠつᶍᄇⅆࡀ⏕ࡌ࡚࠾ࡾ㸪୰࣭ᑠ࣐ࢢ࣐౪⤥⣔ࡢゎ᫂ࡶ㸪ᕧ ࣐ࢢ࣐⁀ࡾࡢ‽ഛ㐣⛬ࢆ▱ࡿ୍ࡘࡢ᪉ἲ࡛࠶ࡿ㸬ᑠつᶍ࣐ࢢ࣐ᄇⅆ࠾࠸࡚ࡣ㸪㝵ẁࣃࢱ࣮ ࣥࢆ༢⣧࡞ᙎᛶࣔࢹ࡛ࣝㄝ᫂ࡋࡓࡀ࠶ࡿ (Miura et al., 2013: Fig. 2)㸬ᕧ࣐ࢢ࣐⁀ࡾ࡛ࡣ⇕ 㔞ࡀࡁ࠸ࡓࡵ㸪ᆅẆࡢᘏᛶⓗࡿ⯙࠸ࢆ⪃៖ධࢀ࡚ࣔࢹࣝࡉࢀࡿᚲせࡀ࠶ࡿ (e.g., Jellinek and DePaolo, 2003; Gregg et al., 2012: Fig. 1)㸬࣐ࢢ࣐⁀ࡾࡢ⇕ⓗไ⣙㛵ࡍࡿ◊✲ࡽ ࡣ㸪ⰼᓵᒾయࡣ࣐ࢢ࣐⁀ࡾࡢ༢ㄪ࡞෭༷࡛ࡣ࡞ࡃ㸪」ᩘᅇࡢ⁀ࡾᙧᡂࢆ⤒ࡿࣔࢹࣝࡀᥦࡉ ࢀ࡚࠸ࡿ (e.g., Annen, 2009)㸬LA-ICP-MS ࢆ⏝࠸ࡓ U-Pb ᖺ௦ ᐃἲࡼࡾ㸪㯮㒊ᕝⰼᓵᒾయ ୰」ᩘࡢ࣐ࢢ࣐㈏ධ࣋ࣥࢺࡀ㆑ูࡉࢀࡓࡀ࠶ࡿ (Ito et al., 2013)㸬ࡇࢀࡽࡢ◊✲ࡸ㸪ࡉ ࡽᵝࠎ࡞ᡭἲࢆ⤌ྜࡏ㸪⥲ྜⓗ࣐ࢢ࣐౪⤥⣔ࡢ㐍ࢆ⌮ゎࡍࡿࡇࡀྍḞ࡛࠶ࢁ࠺㸬 ᩥ⊩: Acocella et al., 2000: 10.1016/S0377-0273(00)00201-8; Annen, 2009: 10.1016/j.epsl.2009.05.006; Deligne et al., 2010: 10.1029/2009JB006554; Gayer and Martí, 2008: 10.1016/j.jvolgeores.2008.03.017; Gregg et al., 2012: 10.1016/j.jvolgeores.2012.06.009; Ito et al., 2013: 10.1038/srep01306; Jellinek and DePaolo, 2003: 10.1007/ s00445-0030277-y; ୕ ᾆ ࣭ ⏣ , 2007: 10.5575/geosoc.113.283; Miura et al., 2013: 10.1130/B30732.1; Roche et al., 2000: 10.1029/1999JB900298; Sato and Taniguchi, 1997: 10.1029/96GL04004; Scandone, 1990: 10.1016/0377-0273(90)90005-Z; Sobradelo et al., 2010: 10.1016/j.jvolgeores.2010.09.003; Spera and Crisp, 1981: 10.1016/0377-0273(81)90021-4; White et al., 2006: 10.1029/2005GC001002. - 36 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-04 㧗⢭ᗘᆅ㟈Ἴࢺࣔࢢࣛࣇ࣮ࡽぢࡓάⅆᒣୗࡢ῝㒊ᵓ㐀 ㉿ 㭉㸦ᮾ࣭⌮㸧 Tomographic imaging of the deep structure of active volcanoes D. Zhao (Dep. Geophys., Tohoku Univ.) E-mail: [email protected] We determined detailed three-dimensional (3-D) images of P and S wave velocity and Poisson’s ratio in the crust and upper mantle beneath NE Japan and SW Japan using a great number of highquality arrival-time data from local crustal earthquakes and intermediate-depth events in the subducting Pacific slab. Then we examined the images beneath the active volcanic areas as well as the source areas of large crustal earthquakes (M 6.0-7.2) which occurred in Tohoku during 1894 to 2014. Among the 26 earthquakes in NE Japan, 10 events occurred in the Tohoku forearc, 10 in the back-arc, and 6 events are located along the volcanic front. Main findings of this work are summarized as follows. (1) Prominent low-velocity (low-V) and high Poisson’s ratio (high-ı) anomalies are revealed in the crust and upper-mantle wedge beneath the active arc volcanoes and the source zones of the large crustal earthquakes. (2) Beneath the volcanic front and back-arc areas, the low-V zones reflect arc-magma related hightemperature anomalies which are produced by joint effects of corner flow in the mantle wedge and fluids from dehydration of the subducting slab. The hot low-V anomalies can cause locally thinning and weakening of the brittle seismogenic crust above them. In addition, low-frequency microearthquakes are observed in the lower crust and uppermost mantle in and around the low-V zones, which reflect ascending of magma and fluids from the mantle wedge to the crust, inducing large crustal earthquakes. (3) No volcano and magma exist in the fore-arc area duo to the low temperature there, hence the lowV zones in the forearc may reflect fluids from the subducting slab dehydration, which may have formed a water wall in the mantle wedge and lower crust. When the fluids enter active faults in the upper crust, the fault-zone friction is reduced and so large earthquakes can be triggered. - 37 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 (4) Our present results as well as some previous studies indicate that the nucleation of a large earthquake is not entirely a mechanical process, but is closely associated with the subduction dynamics and physical and chemical properties of rocks in the crust and upper mantle. In particular, the arc magma and fluids play an important role in the earthquake nucleation. These results have important implications for the reduction of seismic hazards. References Zhao, D., W. Wei, Y. Nishizono, H. Inakura (2011) Low-frequency earthquakes and tomography in western Japan: Insight into fluid and magmatic activity. J. Asian Earth Sci. 42, 1381-1393. Zhao, D., T. Yanada, A. Hasegawa, N. Umino, W. Wei (2012) Imaging the subducting slabs and mantle upwelling under the Japan Islands. Geophys. J. Int. 190, 816-828. Zhao, D., H. Kitagawa, G. Toyokuni (2015) A water wall in the Tohoku forearc causing large crustal earthquakes. Geophys. J. Int. 200, 149-172. Zhao, D. (2015) The 2011 Tohoku earthquake (Mw 9.0) sequence and subduction dynamics in Western Pacific and East Asia. J. Asian Earth Sci. 98, 26-49. - 38 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-05 㜿⸽-4ⅆ○ὶሁ✚≀ࡢᩳ㛗▼࠾ࡼࡧ࣓ࣝࢺໟ᭷≀ࡽࡳࡓ ࣐ࢢ࣐⤌ᡂࡢ㛫ኚ ᒣᓮ⚽ே࣭㛗㇂୰㸦⇃ᮏ࣭⮬↛⛉Ꮫ㸧࣭Ᏻ⏣ ᩔ㸦ᮾிᆅ㟈◊㸧 Temporal variation of magma composition as observed by plagioclase and melt inclusions in Aso-4 pyroclastic flow deposit H. Yamasaki, T. Hasenaka (GSST, Kumamoto Univ.) and A. Yasuda (Earthquake Res. Inst., Univ. of Tokyo) ⣙ 9 ᖺ๓㉳ࡇࡗࡓ㜿⸽-4 ⅆ○ᄇⅆࡣ᪥ᮏ࠾ࡅࡿ᭱つᶍࡢᄇⅆ࡛࠶ࡿୖ㸪ᄇฟ≀ ࡢᒙᗎᏛⓗ㛵ಀࡀከࡃࡢ◊✲⪅ࡼࡗ࡚᫂ࡽࡉࢀ࡚࠾ࡾ㸪ᕧⅆ○ᄇⅆࡢ᥎⛣ࢆ◊✲ࡍ ࡿࡣ᭱㐺࡛࠶ࡿ㸬ࡲࡓ࢝ࣝࢹࣛእ࡛ࡣᕧⅆ○ᄇⅆ┤๓ࡢᄇฟ≀ࡀᚓࡽࢀࡿࡢ࡛㸪‽ഛ㐣 ⛬ࡢ◊✲ࡶ㐺ࡋ࡚࠸ࡿ㸬ᮏⓎ⾲࡛ࡣ㜿⸽-4 ⅆ○ὶሁ✚≀ྵࡲࢀࡿ㖔≀ࡢ⤌ᡂኚ㸪࠾ࡼ ࡧࡑࢀࡽࡢ㖔≀ྵࡲࢀࡿ࣓ࣝࢺໟ᭷≀ࡢ⤌ᡂኚࢆሗ࿌ࡍࡿ㸬ศᯒヨᩱࡣ㸪㜿⸽-4 ⅆ○ᄇ ⅆึᮇࡢᑠ㇂㍍▼ὶሁ✚≀㸦௨ୗ㸪ᑠ㇂㸧 㸪⫧⊦ⅆᒣ⅊ὶሁ✚≀㸦௨ୗ㸪⫧⊦㸧 㸪ඵዪ㍍▼ὶ ሁ✚≀㸦௨ୗ㸪ඵዪ㸧 㸪ᘚࢫࢥࣜὶሁ✚≀㸦௨ୗ㸪ᘚ㸧ࡢᩳ㛗▼ᩬᬗ㸪࠾ࡼࡧᩬᬗ㖔 ≀ྵࡲࢀࡿ࣓ࣝࢺໟ᭷≀࡛࠶ࡿ㸬ྛࢧࣈࣘࢽࢵࢺࡢ㍍▼㸪ⅆᒣ⅊ᒙヨᩱࡽᩬᬗ㖔≀ࢆศ 㞳ࡋ㸪㖔≀ࡢࡳࡢⷧ∦ࢆసᡂࡋ㸪⇃ᮏᏛ⌮Ꮫ㒊࠾ࡼࡧᮾிᏛᆅ㟈◊ࡢ EPMA ࡼࡗ࡚ Ꮫศᯒࢆ⾜ࡗࡓ㸬ࡲࡓᮾிᏛᆅ㟈◊࡛ࡣ FT-IR ࡼࡿྵỈ㔞ࡢ ᐃࡶ⾜ࡗࡓ㸬 ㍍▼୰ྵࡲࢀࡿᩳ㛗▼ࡢ⤌ᡂࡣ⤌ᡂศᕸᖜࡢࣆ࣮ࢡ୰ኸ್ࡀ㸪An㸻35%㸦⫧⊦㸧㸪 An40%㸦ᑠ㇂㸪ඵዪ㸧 㸪An45%㸦ᘚ㸧ᒙᗎᚑࡗ࡚ࢃࡎ࡛ࡣ࠶ࡿࡀቑຍࡍࡿഴྥࡀぢ ࡽࢀࡿ㸬ࡲࡓ⤌ᡂศᕸࡶ༢୍ࣆ࣮ࢡ㸦⫧⊦㸧ࡽ㧗 An ഃᙅ࠸ࣆ࣮ࢡࢆᣢࡘࡶࡢ㸦ᑠ㇂㸪 ඵዪ㸪ᘚ㸧ኚࡋ࡚࠸ࡁ㸪ᩳ㛗▼⤌ᡂࡢᖜࡀࡼࡾᗈࡃ࡞ࡿ㸦ᘚ㸧 㸬ࢥ࣒ࣜศࡅ ࡚ศᯒࡋࡓࡀ㸪᫂ࡽ࡞㏫⣼ᖏᵓ㐀ࡣぢࡘࡽ࡞ࡗࡓ㸬 ᒾᏛ⤌ᡂ࡛ࡣ⫧⊦㸪ᑠ㇂㸪ඵዪ㸪ᘚ㸦㍍▼㸧ࡣ SiO2=68~70%㞟୰ࡋ࡚࠾ࡾ㸪⤌ ᡂࡢ㐪࠸ࡣㄆࡵࡽࢀ࡞࠸㸬ࡋࡋ㸪ᩳ㛗▼㸪ᩳ᪉㍤▼ᩬᬗྵࡲࢀࡿ࣓ࣝࢺໟ᭷≀ࡢ࢞ࣛࢫ ࡛ࡣ㸪ศᯒࡋࡓ⫧⊦ᑠ㇂ࡢ㛫࡛᫂░࡞㐪࠸ࡀㄆࡵࡽࢀࡓ㸬⫧⊦ࡢ࣓ࣝࢺໟ᭷≀ࡣ SiO2=73~74%ࡢ⊃࠸⤌ᡂ㡿ᇦศᕸࡍࡿࡀ㸪ᑠ㇂ࡢ࣓ࣝࢺໟ᭷≀ࡣ⫧⊦ࡢ⤌ᡂ㡿ᇦࢆྵࡳ㸪 SiO2=71~74%ࡢࡸࡸᗈ࠸⤌ᡂ⠊ᅖࢆ♧ࡍ㸬᳝ཎ㸦2014㸧ࡀ㸪࢝ࣝࢹࣛᮾ᪉ࡢ Aso-4A ࢸࣇࣛ ࡛ྠᵝࡢ㛵ಀࢆࡶࡘ 2 ✀ࡢ࢞ࣛࢫ⤌ᡂࢆሗ࿌ࡋ࡚࠾ࡾ㸪ࡑࢀࡽࡣ⫧⊦ඵዪࡢⅆ○ὶሁ✚≀ ࡢ࢞ࣛࢫᑐᛂࡍࡿࡇࢆ㆟ㄽࡋࡓ㸬᳝ཎ㸦2014㸧ࡢඵዪࡀ㸪ᮏㄽࡢᑠ㇂ఝ㏻ࡗࡓ⤌ᡂࢆ - 39 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ♧ࡍࡇࡽ㸪༡࠾ࡼࡧす᪉ὶࢀࡓᑠ㇂ⅆ○ὶ᪉ὶࢀࡓඵዪⅆ○ὶࡀ㸪ࡰྠࡌ࣐ ࢢ࣐౪⤥⣔⏤᮶࡛࠶ࡿࡇࡀ᥎ᐹࡉࢀࡿ㸬 ྵỈ㔞ࡣ⫧⊦ࡢ࣓ࣝࢺໟ᭷≀ࡣ 4%௨ୖ㸪ࢩࣜ࢝ࡸࡸஈࡋ࠸ᑠ㇂࢞ࣛࢫໟ᭷≀ࡣ 2~4%࡛࠶ࡗࡓ㸬ሷ⣲⃰ᗘࡣ⫧⊦ࡢ࣓ࣝࢺໟ᭷≀ࡢ᪉ࡀᑠ㇂ࡼࡾ㧗࠸ࡀ㸪◲㯤ࡣࢩࣜ࢝ஈ ࡋ࠸ᑠ㇂ࡢ᪉ࡀࡸࡸ㧗࠸ྵ᭷㔞ࢆ♧ࡍ㸬 ௨ୖࢆࡲࡵࡿ㸪⫧⊦ࡣ 1 ࡘࡢ࣐ࢢ࣐ᾮ┦ࢆ㸪ᑠ㇂㸪ඵዪ㸪ᘚࡣ 2 ࡘࡢ࣐ࢢ࣐ᾮ┦ࢆ ௦⾲ࡍࡿ⪃࠼ࡽࢀࡿ㸬⫧⊦ᄇฟࡣ࣐ࢢ࣐ᾮ┦㒊ศࡀᆒ㉁࡛࠶ࡾ㸪ᩳ㛗▼ࡣࡑࢀᖹ⾮࡛ ࠶ࡗࡓ⪃࠼ࡽࢀࡿ㸬ࡇࢀᑐࡋ㸪ᑠ㇂㸪ඵዪ㸪ᘚ࡛ࡣ」ᩘࡢ࣐ࢢ࣐ᾮ┦ࡑࢀࡽᖹ⾮ ࡞ᩳ㛗▼ࡀᏑᅾࡍࡿ㸬ࡇࢀࡽࡢࢹ࣮ࢱࢆ᭱ࡶㄝ᫂ࡋࡸࡍ࠸ࣔࢹࣝࡣᡂᒙ࣐ࢢ࣐⁀ࡲࡾࡢୖᒙ ࡽࡢẁ㝵ⓗ࡞࣐ࢢ࣐ฟ㸪ΰྜ࡛࠶ࢁ࠺㸬 - 40 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-06 㨣⏺࢝ࣝࢹࣛࡢ࢝࣍ࣖᄇⅆ ᑠᯘဴኵ㸦㮵ඣᓥᏛ㸧࣭ᡂᑿⱥோ㸦Ṋᒸྎ㧗ᰯ㸧 The 7.3 cal kBP Kika Akahoya eruption of Kikai caldera T. Kobayashi (Kagoshima Univ.) and H. Naruo (Takeokadai Senior High School) 㸯 㨣⏺࢝࣍ࣖᄇⅆࡢᴫせ 㨣⏺࢝ࣝࢹࣛࡣ㸪㮵ඣᓥ┴⸃ᦶ༙ᓥࡽ༡᪉⣙50 km⨨ࡍࡿᾏᗏ࢝ࣝࢹ࡛ࣛ࠶ࡾ㸪 ࡇࡇ࡛ࡣ7.3 cal kBP㸦ዟ㔝㸪2002㸧㨣⏺࢝࣍ࣖᄇⅆୗࡼࡤࢀࡿつᶍ࡞࢝ࣝࢹࣛᙧᡂ ᄇⅆࡀⓎ⏕ࡋࡓ㸬ᄇⅆࡣ๓༙ࡢࣉࣜࢽ࣮ᘧᄇⅆᚋ༙ࡢつᶍⅆ○ὶᄇⅆᘬࡁ⥆ࡃ࢝ࣝࢹ ࣛᙧᡂࡽ࡞ࡾ㸪ࡑࢀࡽࡣ㐃⥆ࡋ࡚Ⓨ⏕ࡋࡓ᥎ᐃࡉࢀࡿ㸦ᑠ㔝࣭㸪1982㸹Maeno and Taniguchi, 2007㸧 㸬๓༙ࡢࣉࣜࢽ࣮ᘧᄇⅆࡢ⤊ᮎࡣᄇ↮୰ᔂቯࡼࡾ㧗 ࡢ⯪ⅆ○ὶࡀⓎ⏕ࡋࡓ㸬ᚋ ༙ࡢᄇⅆ࡛ࡣ⸃ᦶ࣭㝮༙ᓥศᕸࡍࡿᖾᒇ㝆ୗ㍍▼㸦Ky-p㸧ᖾᒇⅆ○ὶሁ✚≀㸦Ky㸧ࡀ ᄇฟࡋࡓ㸦Ᏹ㸪1973㸧 㸬ୖ✵⯙࠸ୖࡀࡗࡓ⣽⢏ⅆᒣ⅊ࡣ㸪㨣⏺࢝࣍ࣖⅆᒣ⅊㸦K-Ah㸸⏫ ⏣࣭᪂㸪1978㸧ࡼࡤࢀ㸪ᮾᆅ᪉ࡲ࡛ศᕸࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸬ᖾᒇ㝆ୗ㍍▼ࡣ⣙20km㸱㸪 ᖾᒇⅆ○ὶሁ✚≀ࡣ⣙50km㸱㸪㨣⏺࢝࣍ࣖⅆᒣ⅊ࡣ100km㸱௨ୖ᥎ᐃࡉࢀ࡚࠸ࡿ㸦⏫⏣࣭ ᪂㸪2003㸧 㸬୍㐃ࡢᄇฟ≀ࡣ㨣⏺࢝࣍ࣖࢸࣇࣛ⛠ࡉࢀ࡚࠸ࡿ㸬 㸰 ᖾᒇⅆ○ὶࡢ฿㐩⠊ᅖ Ky ࡣᴟࡵ࡚ⷧࡃᣑࡀࡗࡓࡀ㸪ࡑࡢ⠊ᅖࡘ࠸࡚༡ഃࡣࢺ࢝ࣛิᓥ㒊㸪ഃࡣ⸃ᦶ༙ᓥ୰ 㒊ࡢ㮵ඣᓥᕷ႐ධ㝮༙ᓥࡢᚿᕸᚿࢆ⤖ࡪ⥺௨༡ࡉࢀ࡚ࡁࡓ㸦⏫⏣࣭᪂㸪㸧 㸬ࡋ ࡋ㸪ࡑࡢᚋࡢ◊✲࡛ᒇஂᓥ༡㒊ࡣ฿㐩ࡏࡎ㸦ୗྖ㸪㸧㸪✀Ꮚᓥ㒊ࡶ฿㐩ࡋ࡞ࡗࡓ 㸦⸨ཎ㸪㸧ࡇࡀ᫂ࡽ࡞ࡗࡓ㸬ࡲࡓ㸪ࢺ࢝ࣛิᓥཱྀஅᓥࡶ฿㐩ࡋ࡞ࡗࡓ㸬 㝮༙ᓥ୰㒊ࡢ⫢ᒓᖹ㔝࡛ࡣ㨣⏺࢝࣍ࣖࢸࣇࣛࡀ᫂░ሁ✚ࡍࡿࡀ㸪࠸ࡎࢀࡢᆅⅬ࠾ ࠸࡚ࡶ Ky-p ࡑࡢୖ㍕ࡿ K-Ah ࡢࡳࡀሁ✚ࡋ Ky ࡣㄆࡵࡽࢀ࡞࠸㸬㝮༙ᓥ༡㒊ࡣᶆ㧗 1000m ㏆࠸ᒣᆅࡀᏑᅾࡍࡿࡀ㸪ᒣᆅ୰⭡ࡣ Ky ࡢሁ✚ࡀㄆࡵࡽࢀࡿࡇࡽ㸪Ky ࡣᒣᆅࢆ ㉺࠼ࡿࡇࡀ࡛ࡁ࡞ࡗࡓ⪃࠼ࡽࢀࡿ㸬 ୍᪉㸪㝮༙ᓥ୰㒊ࡢ㮵ඣᓥ‴㠃ࡋࡓ㮵ᒇᕷ㧗㡲ࡸⰼᒸ࡛ࡣ㸪ࢃࡎ࡛࠶ࡿࡀⰋࡃⓎἻ ࡋࡓᩘ cm ࡢ㍍▼ࡀⅬᅾࡍࡿࡇࡽ㸪Ky ࡣ฿㐩ࡋࡓ⤖ㄽ࡙ࡅࡽࢀࡿ㸬Ky ࡣ㮵ඣᓥ‴ἢ ࠸ᾏୖࢆୖࡋ㸪‴ἢࡗࡓ༙ᓥࡢᩳ㠃ࢆὶ㉮ࡋ㥑ࡅୖࡗࡓࡶࡢ࡛࠶ࢁ࠺㸬 ᮾࢩࢼᾏഃࡢ⸃ᦶ༙ᓥ࡛ࡣ㸪᪥⨨ᕷ྿ୖ༡㒊ࡲ࡛ Ky ࡀ☜ㄆࡉࢀࡿࡀ㸪ࡑࢀࡼࡾ௨࡛ࡣ K-Ah ࡢࡳࡀሁ✚ࡍࡿ㸬㮵ඣᓥ‴ἢ࠸࡛ࡣ㮵ඣᓥᕷ႐ධࡢ㒊ࡲ࡛ Ky ࡀሁ✚ࡋ㸪ᶆ㧗 500m - 41 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ௨ୖࡢᒣᆅࡶሁ✚ࡋ࡚࠸ࡿ㸬ࡋࡓࡀࡗ࡚㸪⸃ᦶ༙ᓥഃ࡛ࡣ྿ୖ༡㒊႐ධ㒊ࢆ⤖ࡪ௨༡ ࡀ฿㐩⠊ᅖ࡞ࡿ㸬 㸱 㨣⏺࢝࣍ࣖᄇⅆ㝶కࡍࡿᆅ㉁⌧㇟ ࢝࣍ࣖᄇⅆ㏆࠸ᮇࡢᆅ㉁⌧㇟ࡋ࡚ࡣ㸪ᩘⓒ㹼100 ᖺ๓つᶍ࡞ᒣᔂࢀ㸦ᒣయᔂ ቯ㸧ὶ⣠ᒾ㉁ࡢ㛗⁐ᒾᄇฟࡀ࠶ࡗࡓ㸦ᑠᯘ࣭㸪2006㸹ᑠᯘ࣭㸪2010㸧 㸬ࡉࡽࡑࢀ௨ ๓ࡣ㛗ᮇࢃࡓࡿ᩿⥆ⓗ࡞ᄇⅆࡢ⏘≀࡛࠶ࡿ⡲ ࢸࣇࣛࡢᄇฟࡀ࠶ࡗࡓ㸦ዟ㔝㸪㸧 㸬 㨣⏺࢝࣍ࣖᄇⅆ࡛ࡣ㸪๓༙ࡢࣉࣜࢽ࣮ᘧᄇⅆ┤ᚋ࠾ࡼࡧᚋ༙ࡢⅆ○ὶᄇⅆ࣭࢝ࣝࢹࣛᙧ ᡂᮇࡢ㸰ᗘࢃࡓࡗ࡚ᆅ㟈ࡀⓎ⏕ࡋࡓ㸦ᡂᑿ࣭ᑠᯘ㸪2002㸧 㸬 ✀Ꮚᓥ࠾ࡼࡧᒇஂᓥ࡛ࡣ᭦᪂ୡᚋᮇࡢẁୣ♟ᒙࡽୖ᪼ࡍࡿᄇ♟⬦ࡢᏑᅾࡍࡿ㸬ᄇ♟⬦ࡣ Ky ┤ୗ㐩ࡍࡿࡀ㸪Ky ࢆ㈏ࡃࡶࡢࡣぢࡽࢀ࡞࠸ࠋKy-p ┤ୗࡢᅵተᒙࡀ Ky-p ୰ୖ᪼ࡍࡿ 㸪ᆅࢀ Ky ࡢࢢࣛࣥࢻ࣮ࣞࣖࡀධࡾ㎸ࡴ࡞ࡽ㸪ᆅ㟈ࡢⓎ⏕ࡣ Ky-p ࡢᄇฟᚋ ࡛ Ky ࡢᄇฟ┤๓࡛࠶ࡗࡓ⤖ㄽ࡙ࡅࡽࢀࡿ㸬 ୍᪉㸪㝮༙ᓥ୰㒊࡛ࡣᄇ◁ࡀ K-Ah ୰ᄇࡁฟࡋ࡚࠸ࡿࡀከᩘᏑᅾࡍࡿ㸬ᄇ◁ࡣ K-Ah ᒙࡢୗഃ 1/㸱⛬ᗘࡢ⨨࡛ᶓᗈࡀࡾ㸪K-Ah ࡢ㝆ୗ㏵୰࡛ᆅ㟈ࡀⓎ⏕ࡋࡓࡇࡣ࠸࡞࠸㸬 㟝ᓥⅆᒣ⩌ࡢ⏋ᓅᒣ㡬ⅆཱྀ࡛ࡣ㸪ὸ࠸†ሁ✚ࡋࡓ K-Ah ࡀぢࡽࢀࡿ㸬K-Ah ᒙෆ㒊ࡣ㢧 ⴭ࡞࣑ࣛࢼࡸࢫࣛࣥࣉᵓ㐀ࡀ࠶ࡾ㸪ࡉࡽ K-Ah ୗ㒊ࡢ∵ࡢࢫࢿⅆᒣ⅊ᒙࡀἼ≧ࢆ࿊ࡋ࡚࠸ ࡿࠋࡇࡢࡼ࠺࡞ᵓ㐀ࡣ K-Ah ᒙࡀ⃭ࡋ࠸㟈ືࢆཷࡅࡓࡇࢆ♧ࡋ࡚࠸ࡿ㸬㟈ືࡢⓎ⏕ࡋࡓ ᮇࡘ࠸࡚ࡣ≉ᐃࡀ㞴ࡋ࠸ࡀ㸪K-Ah ᒙୖ㒊ࡀỈᖹ࡛࠶ࡿࡇࡽࡍࡿ㸪K-Ah 㝆ୗ㏵୰࡛ Ⓨ⏕ࡋࡓᆅ㟈ࡼࡿࡶࡢࡶࡋࢀ࡞࠸㸬 ⅆ○ὶࡼࡾᶞᮌࡀᶓ㌿ࡍࡿࡇࡣᱜᓥࡢṇᄇⅆ࡞࡛ࡶ▱ࡽࢀ࡚࠸ࡿࡀ㸪ᶞᮌࡶ ᆅᒙࡀᶓ㌿ࡍࡿࡀ Ky క࠺ᆅ㉁⌧㇟ࡋ࡚Ꮡᅾࡍࡿ㸦ᮏ◊✲㞟㸪ᡂᑿ㸧 㸬୍⯡ⓗ࡞ ࡁࡉࡣᚄ㸯㹼㸳㹫࡛࠶ࡾ㸪῝ࡉ㸯㹼㸰㹫ࡲ࡛ࡢྂᅵተᒙ࣭ࢸࣇࣛᒙࡀᩘ༑㹼90rᶓ㌿ࡍࡿ㸬 ᶓ㌿᪉ྥࡣࡰ࡛࠶ࡾ㸪㨣⏺࢝ࣝࢹࣛᑐ᪉ྥ࡛࠶ࡿ㸬 ⸃ᦶ༙ᓥ༡㒊ᾏᓊἢ࠸࡛ࡣ Ky ࡢ◚∦ࢆྵࡴ♟ᒙࡀᏑᅾࡍࡿ㸬♟ࡣᵝࠎ࡞ᙧ≧ࢆ࿊ࡍࡿࡀ ♟ࡶᑡ࡞ࡽࡎྵࡲࢀࡿ㸬ࡇࡢ♟ᒙࡣᶆ㧗 30m ⛬ᗘࡢ⨨࠶ࡾ㸪㏆㢧ⴭ࡞Ἑᕝࡣ࡞ ࡃ㸪♟ᒙࡣἙᕝ௨እࡢႠຊ㸪࠼ࡤὠἼ࡛㐠ࡤࢀ࡚ࡁࡓࡇ࡞ࡀ⪃࠼ࡽࢀࡿ㸬ࡍ࡛㸪ᚋ ༙ࡢⅆ○ὶᄇⅆ࣭࢝ࣝࢹࣛᙧᡂᮇࡣᕧὠἼࡀⓎ⏕ࡋࡓྍ⬟ᛶࡀᣦࡉࢀ࡚࠸ࡿ㸦⸨ཎ࣭ 㸪2010㸹ᑠᯘ㸪2008㸹Maeno and Imamura, 2007 ࡞㸧㸬 ᒇஂᓥ࡛ࡣ Ky ୰ᶞᮌࡀྵࡲࢀࡿࡀከᩘ࠶ࡿࡀ㸪࠸ࡎࢀࡢᶞᮌࡶⅣࡋ࡚࠸࡞࠸㸬ࡲ ࡓ㸪ᐑஅᾆᕝࡸᏳᡣᕝἢ࠸࡛ࡣ Ky ୰◁ࡸ♟ࡀධࡾ㎸ࡴࡀ࠶ࡾ㸪ᑠ℩⏣ࡢᾏᓊ࡛ࡣ♟ᒙ୰ Ky ࡢ୍ḟሁ✚≀ࡀᣳࡲࡗ࡚࠸ࡿ㸬ࡇࢀࡽࡢ㉳※ࡘ࠸࡚ࡣ Ky ሁ✚ᚋࡢࣛࣁ࣮ࣝሁ✚≀ࡢ ྍ⬟ᛶ㸪ὠἼሁ✚≀ࡢྍ⬟ᛶࡘ࠸࡚㸪ᚋ㸪ヲ⣽᳨ウࡋ࡚࠸ࡃணᐃ࡛࠶ࡿ㸬 - 42 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-07 ᱜᓥⅆᒣࡢᄇⅆྐࡽࡳࡓ⸃ᦶᄇⅆࡢྍ⬟ᛶ ዟ㔝 㸦⚟ᒸ㸧 Possibility of the biggest eruption of Sakurajima volcano, viewed from eruptive history M. Okuno (Fukuoka Univ.) ᱜᓥⅆᒣࡣ㸪ጸⰋ࢝ࣝࢹࣛࡢᚋ࢝ࣝࢹࣛⅆᒣ࡛࠶ࡾ㸦ᑠᯘ㸪2013㸧㸪29 kcal BP㸦ዟ㔝㸪 2002㸧ࡢධᡞⅆ○ᄇⅆ㸦௨ୗ㸪A-Tn ࠸࠺㸧ࡽࢃࡎ 2000 ᖺᚋ᭱ึࡢࣉࣜࢽ࣮ᘧᄇⅆ 㸦P17㸧ࢆ㛤ጞࡋ࡚࠸ࡿ㸦Okuno et al., 1997㸧 㸬ᱜᓥࡢᄇⅆྐࡣ㸪ྂᮇᓅ㸪᪂ᮇᓅ㸪༡ᓅ 㸱ࡘࢫࢸ࣮ࢪ༊ศ࡛ࡁࡿࡀ㸪ᑠᯘ㸦2013㸧ࡣṔྐ௦ࡢኳᖹᐆᏐ㸦764ࠥ766㸧 㸪ᩥ᫂㸦1471 ࠥ1476㸧 㸪ᏳỌ㸦1779㸧 㸪ṇ㸦1914㸧ࡢつᶍ࡞ࣉࣜࢽ࣮ᘧᄇⅆࢆ୰ᚰࡋࡓάືࢆ㸪᪂ᮇ༡ ᓅࢫࢸ࣮ࢪࡋ࡚⊂❧ࡉࡏࡓ㸬2015 ᖺ⌧ᅾࡶ㸪ⅆཱྀࢆ୰ᚰࣈࣝ࢝ࣀᘧᄇⅆࢆάⓎ⥆ ࡅ࡚࠸ࡿ㸬⣙ 13 cal kBP ࡢᱜᓥ⸃ᦶࢸࣇࣛ㸦SzѸS㸭P14㸧ࡣᱜᓥⅆᒣ᭱ࡢࢸࣇ࡛ࣛ㸪༡ᕞ ୍ศᕸࡋ㸦Fig. 1㸧 㸪ࡳࡅࡢయ✚ࡣ 14 km3 ᥎ᐃࡉࢀ࡚࠸ࡿ㸦ᑠᯘ㸪2013㸧㸬ࡇࡢ Sz ѸS ᄇⅆࡽ᪂ᮇᓅࢫࢸ࣮ࢪࡀ㛤ጞࡋࡓࡀ㸪ࡑࡢ๓ࡣ 1 ᖺ௨ୖࡢఇṆᮇࡀ࠶ࡿ㸦Fig. 2㸸 Okuno et al., 1997㸹ዟ㔝㸪2002㸧㸬ࡲࡓ㸪ࡇࡢఇṆᮇࡣ㸪㧗㔝࣮࣋ࢫࢧ࣮ࢪ㸦A-Tkn㸧ࡸ᪂ᓥ ⅆ○ὶ㸦A-Sj㸧࡞ࡢጸⰋ࢝ࣝࢹࣛ㉳※ࡢࢸࣇࣛࡀᑠつᶍ࡞ࡀࡽᄇฟࡋ࡚࠸ࡿ㸬 ᱜᓥጸⰋ࢝ࣝࢹࣛࡢ࣐ࢢ࣐⁀ࡲࡾࡣ㏆᥋ࡋ࡚࠸ࡿ⪃࠼ࡽࢀ㸪ࡇࡢࡼ࠺࡞ጸⰋ࢝ࣝࢹࣛ ࡢ࣐ࢢ࣐ᄇฟࡀ㸪ᱜᓥⅆᒣࡢ㛗࠸ఇṆᮇࢆᐇ⌧ྍ⬟ࡋࡓࡢ࡛࠶ࢁ࠺㸬ࡉࡽ㸪ᱜᓥࡢ᭱ึ ࡢ P17 ᄇⅆࡣ㸪య✚ 500 km3 ࡢ A-Tn ᄇⅆࡽ࠶ࡲࡾ㛗࠸ఇṆᮇࢆᣳࡲࡎ࠾ࡇࡗ࡚࠸ࡿ㸬ࡇ ࡢࡇࡶ㸪୧⪅ࡢ࣐ࢢ࣐⁀ࡲࡾࡀ⊂❧࣭୪⾜ࡋ࡚άືࡋ࡚࠸ࡿࡇࢆ♧ࡍ㸬ࡇࡢ P17 ࡢయ✚ ࡀ 1.1 km3 SzѸS ḟࡄつᶍ࡛࠶ࡿࡇࡶ㸪ࡑࡢࡇࢆᙉࡃ♧၀ࡍࡿ㸬㨣⏺࢝ࣝࢹ࡛ࣛࡶ࢝ ࣝࢹࣛᙧᡂᄇⅆᚋ࢝ࣝࢹࣛᄇⅆ࡛ྠᵝࡢ㛫㛵ಀࡀ࠶ࡾ㸦ዟ㔝㸪2002㸧 㸪࢝ࣝࢹࣛⅆᒣ࡛ࡣ ୧⪅ࡀྠ୪⾜ⓗ㐍ࢇ࡛࠸ࡿࡢ࡛࠶ࢁ࠺㸬௨ୖࡢࡼ࠺㸪 ᱜᓥⅆᒣࡢᄇⅆྐࢆ═ࡵࡿ㸪 SzѸS ᄇⅆࡀᴟࡵ࡚≉ู࡛࠶ࡿࡇࡀࢃࡿ㸬ࡋࡓࡀࡗ࡚㸪᪂ᮇ༡ᓅࢫࢸ࣮ࢪ࠶ࡿᱜᓥⅆᒣ ࡛㸪㏆࠸ᑗ᮶ SzѸS ࡢࡼ࠺࡞つᶍࡢᄇⅆࡀ࠾ࡇࡿࡣ⪃࠼㞴࠸㸬ࡑࢀࡼࡾࡶࡴࡋࢁ㸪ጸⰋ࢝ ࣝࢹࣛࡣ 16 cal kBP ࡢ A-Sj ௨㝆㸪᫂☜࡞ᄇⅆάືࡀㄆࡵࡽࢀࡎ㸪⌧ᅾࡲ࡛ࡢ⛬ᗘࡢ࣐ࢢ ࣐ࢆ✚ࡋ࡚ࡁࡓࢆヲࡋࡃぢ✚ࡶࡿᚲせࡀ࠶ࢁ࠺㸬ࡇࡢぢ✚ࡶࡾࡀ᫂☜࡞ࢀࡤ㸪ጸⰋ࢝ ࣝࢹࣛࡢḟࡢ࢝ࣝࢹࣛᄇⅆࡢつᶍࡀ᥎ᐃ࡛ࡁࡿ㸬 - 43 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 Fig. 1 Fig. 2 Isopach map of Sakurajima-Satsuma (P14) tephra (after, Kobayashi et al., 2013). Cumulative tephra (bulk) volume for Sakurajima volcano (after, Kobayashi et al., 2013). - 44 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-08 ᆅ⊹ࡸ Ἠᆅᇦㄆࡵࡽࢀࡿ㧗 㓟ᛶࡢⅆᒣᛶὶయࡢྡṧࡾ ⏣ཱྀᖾὒ㸦⚟ᒸ࣭⌮㸧 Remnan of volcanic fluid in geothermal manifestations such as steaming ground and hot springs 㸫a good monitoring point for big eruptions?㸫 S. Taguchi (Fukuoka Univ.) ⅆᒣࡢ࿘㎶Ⓨ㐩ࡍࡿᆅ⇕ᆅᖏࡣᄇẼᖏࡸ Ἠ࡞ࡢᆅ⇕ᚩೃࡀศᕸࡋ࡚࠸ࡿ㸬ࡇࡢࡼ ࠺࡞ᆅ⇕ᚩೃᆅࡢ࡞ࡣ㸪ࡘ࡚㧗 ࡢⅆᒣᛶὶయࡀస⏝ࡋࡓྡṧࡾࡀㄆࡵࡽࢀࡿ㸬ࡇࡢ ࡼ࠺࡞㊧ࡣ㸪ⅆᒣᛶὶయࡀ࣐ࢢ࣐ࡽⓎᩓࡉࢀ㸪ẚ㍑ⓗ࿘㎶ࡢᒾ▼ᛂࡏࡎᆅ⾲฿㐩 ࡋࡓᚋ࡛࠶ࡾ㸪ᆅୗ῝㒊┤⤖ࡋ࡚࠸ࡿ㏻㊰࡛ࡶ࠶ࡿ㸬ࡇࡢࡼ࠺࡞ᆅ⇕ᚩೃᆅࡢヲ⣽࡞ᢕᥱ ࡣ㸪 Ἠࢆྵࡴᆅ⇕⣔ࡢṔྐࡸ⌧≧ࡢ⌮ゎࢆ῝ࡵࡿࡤࡾ࡛࡞ࡃ㸪㜵⅏ୖࡶ㔜せ࡞ሗࢆ ࠼࡚ࡃࢀࡿྍ⬟ᛶࡀ࠶ࡿ㸬 ࡇࡇ࡛ࡣ㔜ࡢⅆᒣάືక࠺ᆅ⇕⣔ࡢⓎ㐩㐣⛬ࡘ࠸࡚㸪ඵཎⓎᆅ⇕ᖏࢆྲྀࡾୖ ࡆ㸪ඵཎࡢᆅ⇕ᚩೃᆅࡣࡘ࡚ⅆᒣᛶὶయࡢ㏻㊰࡛࠶ࡗࡓࡇࢆ⤂ࡍࡿ㸦Fig. 1㸧 㸬 ඵཎᆅ⇕ᖏࡢ㒊ࡣᄇẼάືࢆక࠺ᑠᯇᆅ⊹ࡀ࠶ࡾ㸪ᆅୗ 1000㹫ࡲ࡛㓟ᛶኚ㉁ᖏࡀ Ⓨ㐩ࡋ࡚࠸ࡿ (Hayashi, 1973㸧 㸬ᑠᯇᆅ⊹ࡢ Ἠࡣ㸪ᆅୗࡢ⇕ỈࡀἛ㦐ࡋ㸪ศ㞳ࡉࢀࡓẼ㸪 ◲Ỉ⣲㸪㓟Ⅳ⣲➼ࡀᆅୗὸᡤୖ᪼ࡋ㸪ᆅ⾲㏆ࡃࡢᆅୗỈࢆຍ⇕ࡋᙧᡂࡉࢀࡓࡶࡢ࡛㸪 Ẽຍ⇕Ỉࡢ SO4 ᆺ㸦◲Ỉ⣲ࡢ㓟ࡼࡿ㸧ࢆ♧ࡋ࡚࠸ࡿ㸬୍⯡ⓗ pH ࡣ 2-4 ⛬ᗘࡢ್ࢆ ♧ࡍ㸬ኚ㉁㖔≀ࡣࢡࣜࢫࢺࣂࣝ▼+᫂♠▼ࡀ༟㉺ࡋ㸪࿘㎶㒊࡛ࡣࡇࢀ࢝࢜ࣜࢼࢺࢆకࡗ࡚ ࠸ࡿ㸬ࡋࡋ࡞ࡀࡽ㸪ᑠᯇᆅ⊹࡛ࡣࡇࡢ୰㸪▼ⱥࡽ࡞ࡿ⌛ᒾࡀᆅ⾲࡛ㄆࡵࡽࢀ㸪⌧ᅾ ࡢᄇẼάືୗ࡛ᙧᡂࡉࢀࡓࡶࡢ࡛࡞࠸ࡇ㸪ࡍ࡞ࢃࡕ pH<2 ࡢ Cl-SO4 ᆺࡢⅆᒣᛶὶయࡀࡘ ࡚స⏝ࡋࡓࡇࢆ♧၀ࡋ࡚࠸ࡿ㸬ࡲࡓ㸪᫂♠▼ࡢ◲㯤ྠయẚࡣ㸪⌧ᅾࡢᄇẼάືୗ㸦Ẽ ຍ⇕Ỉࡢస⏝㸧࡛࡛ࡁࡓࡇࢆ♧ࡋ࡚࠸ࡿࡀ㸪୰ࡣࡼࡾ㧗 㓟ᛶୗࡢ᮲௳ୗ࡛ᙧᡂࡋࡓࡶ ࡢ࡛࠶ࡿࡇࢆ♧ࡍࡶࡢࡶㄆࡵࡽࢀࡿ㸬 ࡇࡢ㏆ࡢᆅୗࡢ⇕Ỉኚ㉁ࡣ㸪᫂ࡤࢇ▼ࡀᆅୗ⣙ 350m ࡲ࡛ཌࡃⓎ㐩ࡋ㸪ࡑࡢୗࡣ࢝࢜ ࣜࢼࢺࡸࣃࣟࣇࣛࢺࡀᆅୗ 1000m ௨ୖࡢ῝ࡉࡲ࡛ศᕸࡋ࡚࠸ࡿ㸬ᆅୗ 100㹫ࡲ࡛ࡢ ᫂ࡤࢇ▼ࡢ◲㯤ࡢྠయẚࡣ 0.5͙⛬ᗘ࡛㸪⌧ᅾࡢᄇẼάືࡢᙳ㡪ୗ࡛⏕ᡂࡋࡓࡇࢆࡋࡵࡋ ࡚࠸ࡿ㸬ࡋࡋ㸪ࡑࢀ௨῝ࡣ 10 ᩘ͙㹼23͙㧗࠸್ࢆ♧ࡋ㸪ᆅ⾲㏆ࡢᄇẼάືࡣ㛵ಀࡢ ࡞࠸ࡇࢆ㸪ࡲࡓࡇࡢࡼ࠺࡞᫂♠▼ࡢࢥࡣ APS 㖔≀ࡀㄆࡵࡽࢀ㸪ⅆᒣάື୰ᚰ㒊ࡢ㧗◲ ⣔ࡢ⎔ቃୗ࡛ᙧᡂࡋࡓࡇࢆ♧ࡋ࡚࠸ࡿ㸬ࡲࡓ㸪᫂ࡤࢇ▼ᖏࡢୗࡢ࢝࢜ࣜࣥ-ࣃࣟࣇ - 45 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࣛࢺᖏࡣ㸪ࢺࣃ࣮ࢬ㸪ࢬࢽ▼㸪⣚ᰕ▼㸪ࢲࢫ࣏࡞㧗 㓟ᛶ㸪ࡍ࡞ࢃࡕⅆᒣᛶὶ యࡢ㏻㊰㏆࡛ᙧᡂࡉࢀࡓ㖔≀ࡶศᕸࡋ࡚࠸ࡿ㸬ࡇࢀࡽࡢࡇࡽ㸪ᑠᯇᆅ⊹㏆ࡣ㸪ࡘ ࡚ࡢ㧗 ࣭㓟ᛶࡢⅆᒣᛶὶయࡢ㏻㊰࠶ࡓࡾ㸪ཌࡃⓎ㐩ࡍࡿ㓟ᛶኚ㉁ᖏࡣࡇࡢάືࡼࡾ⏕ ᡂࡋࡓࡶࡢ࡛࠶ࡿࡇࡀ᫂ࡽ࡛࠶ࡿ㸬࡞࠾㸪ඵཎ㒊ࡣ⌧ᅾࡶ㓟ᛶࡢ㧗 ⇕ỈࡀᏑᅾ ࡋ࡚࠾ࡾ㸪⌧ᅾࡶⅆᒣᛶὶయࡢάືࡀ⥆࠸࡚࠸ࡿ⪃࠼ࡽࢀࡿ㸬 ඵཎࡢ 2km ⨨ࡍࡿᓅ࡛ࡣ㸪᫂ࡤࢇ▼ᖏࡢ◲㯤ྠయẚࡣⅆᒣᛶὶయࡢᏑᅾୗ࡛ ᙧᡂࡉࢀࡓࡇࢆ♧ࡋ࡚࠸ࡿࡀ㸪⌧ᅾ࡛ࡣᆅୗ㛵㐃ࡋࡓ㓟ᛶࡢ⇕Ỉࢆぢฟࡍࡇࡀ࡛ࡁ࡞ ࠸㸬ᓅ㸫ඵཎᆅ⇕ᖏ࡛ㄆࡵࡽࢀࡿࡼ࠺࡞ⅆᒣᛶὶయࡀస⏝ࡋࡓ㊧ࡣ㸪㔜ⅆᒣࡢ࿘㎶ ࡢ Ἠᆅࡢ㸪ᕞྛᆅࡢⅆᒣ࿘㎶ࡢᆅ⊹ࡸ Ἠ࡞ࡶぢฟࡉࢀࡿ㸬 ࡇࡢࡼ࠺࡞ⅆᒣᛶὶయࡢྡṧࡾࢆక࠺ᆅ⇕ᚩೃᆅࡣ㸪ࡑࡢ㏻㊰ࡀᆅୗ῝㒊ࡢ㧗 㒊┤᥋ ࡘ࡞ࡀࡗ࡚࠸ࡿ⪃࠼ࡽࢀࡿࡢ࡛㸪つᶍᄇⅆࡢ㝿ࡢᚩೃࡀ࠸ࡕ᪩ࡃ᳨▱ࡉࢀࡿሙ࡞ࡿྍ ⬟ᛶࡀ࠶ࡿ㸬࡞࠾㸪ࣆࢼࢶ࣎ⅆᒣࡶⅆᒣᛶὶయࡢᚩೃᆅࡣᏑᅾࡋ࡚࠸ࡓࡀ㸪ᄇⅆ┤๓ࡢኚ ࡘ࠸࡚ࡣሗ࿌ࡀ࡞ࡉࢀ࡚࠸࡞࠸㸬 Fig. 1 Schematic geothermal model of Otake-Hatchobaru geothermal model (After modified Taguchi, et al, (2001). - 46 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 3-09 ⅆᒣάືึᮇࡢࢸࣇࣛࢆࡗࡓᒾ▼Ꮫⓗࣔࢽࢱࣜࣥࢢ ʊࢭࣥࢺ࣊ࣞࣥࢬⅆᒣ 1980 ࡢ࣮ Ώ㑓බ୍㑻㸦ᕞ㸧 Petrological monitoring using early tephra for volcanic activity - Case study of Mt. St. Helense 1980 eruptionK. Watanabe (Kyushu Univ.) - 47 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 4-01 Eruptions at Sinabung and Kelud in Indonesia S. Nakada (ERI, Univ. Tokyo), M. Yoshimoto (Mt. Fuji Res. Inst.), F. Maeno (ERI, Univ. Tokyo), M. Iguchi (DPRI, Kyoto Univ.), A. Zaennudin (CVGHM) and M. Hendrasto (CVGHM) ࣥࢻࢿࢩ㸪ࢩࢼࣈࣥⅆᒣࢣ࣮ࣝࢺⅆᒣࡢᄇⅆ ୰⏣⠇ஓ(ᮾி)࣭ྜྷᮏᏹ(ᐩኈⅆᒣ◊)࣭๓㔝 ῝(ᮾி)ཱྀ࣭ṇே(ி㒔)࣭ A. ࢨ࢚ࢾࢹࣥ (ࣥࢻࢿࢩⅆᒣᆅ㉁⅏ᐖ㍍ῶࢭࣥࢱ࣮)࣭ M. ࣊ࣥࢻࣛࢫࢺ (ࣥࢻࢿࢩⅆᒣᆅ㉁⅏ᐖ㍍ῶࢭࣥࢱ࣮) In Indonesia, two distinct eruptions occurred at Sinabung and Kelud in 2014. The geophysical and geological observation and petrological research on these eruptions provide us an important key question; why two different modes of eruption occurred under a similar volcanological background. Lava dome-forming eruption started at Sinabung volcano, Northern Sumatra, in the end of 2013, which was preceded by the phreatic eruption period since 2010. The eruption had continued in a nearly constant rate of magma effusion as of the summer of 2014. The 2010 eruption was the first historic eruption, and the latest eruption geologically recorded occurred in the 9-10th Century. This time eruption was very similar to the 9-10th Century eruption in terms of style, scale, position and magma chemistry; that is the growth of a lava flow/dome complex in the summit area and generation of collapsed-type block-and-ash flows. This time, the lava complex extended on the southeastern volcano slope, frequently generating pyroclastic density currents, and became horizontally about 3 km long from the source (Fig. 1). The volume of erupted magma reached about 0.13 km3. The lava is porphyritic hornblende-bearing two pyroxene andesite (SiO2 57-58%) and high-Si rhyolite melt (SiO2 ~75%). The geological study showed the absence of explosive eruption in this volcano through its growth history. On the other hand, the Plinian eruption began at Kelud volcano, east Java on the evening of February 13, 2014, which had declined almost within about 6 hours. The eruption cloud rose to 18-25 km above the crater, and tephra deposited on extensive areas. The precursory seismic activity started two weeks before the eruption and the intensity increased with time. This short but explosive eruption was one of recent large eruptions (VEI 4) typical at Kelud, which repeated every about 20 years. Before this eruption, a lava dome complex of about 0.04 km3 had been formed within the crater in 2007-2008 (Fig.2). The total volume of tephra of the 2014 eruption is 0.2 to 0.3 km3 in DRE. The magma is crystalrich (about 60 vol.%), porphyritic pyroxene andesite (SiO2 55-56%) with rhyolite melt (SiO2 ~70%). The petrological characteristics of the magma are similar to the 2007-2008 lava dome, except the foam glassy groundmass in the former. The 2013-2014 eruption at Sinabung and the February 2014 eruption at Kelud are good examples of less-explosive and explosive eruptions in Indonesia, respectively. The magnitudes of eruption are similar in orders between the two volcanoes, and the magma compositions are basaltic andesite to andesite. Magma storage depths and the resultant estimated water contents were similar to each other. However, the eruption rates were different; ~5 m3/s and 20,000 to 40,000 m3/s for Sinabung and Kelud, respectively (Fig. 3). At Kelud, the compositionally identical magma erupted both explosive and nonexplosive for these 6 years. A critical difference of eruptions between two volcanoes and in a single volcano is the eruption rate. (Modified from the abstract read in the 2014 AGU Fall Meeting) - 48 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 2014 ᖺࣥࢻࢿࢩ࡛ࡣࢩࢼࣈࣥⅆᒣࢣ࣮ࣝࢺⅆᒣ࡛␗࡞ࡿࢱࣉࡢᄇⅆࡀ㉳ࡁࡓࠋ ᆅ⌫≀⌮Ꮫⓗ࠾ࡼࡧᆅ㉁Ꮫⓗほ ᒾ▼Ꮫⓗ◊✲ࡽ㸪ࡇࢀࡽ 2 ⅆᒣࡀఝࡓᆅ㉁Ꮫⓗ⫼ᬒ࡛ ࠺ࡋ࡚␗࡞ࡿࢱࣉࡢᄇⅆࢆࡍࡿࡢ࠸࠺ᇶᮏⓗ࡞ၥࢆᢞࡆࡘࡅࡓࠋ ࢫ࣐ࢺࣛ࠶ࡿࢩࢼࣈࣥⅆᒣ࡛ࡣ 9 ୡ⣖ࡽ 10 ୡ⣖ࡢⅆ○ὶᄇⅆࡀ᭱ࡶ᪂ࡋࡗࡓࡀ㸪 2010 ᖺ 8㸪9 ᭶᭷ྐึࡵ࡚ࡢᄇⅆ㸦ỈẼ⇿Ⓨ㸧ࢆ㉳ࡇࡋࡓࠋ2013 ᖺ㸷᭶୰᪪ỈẼ⇿ Ⓨࡀ㛤ࡋ㸪࣐ࢢ࣐ỈẼ⇿Ⓨࢆ⧞ࡾ㏉ࡋ㸪12 ᭶ᒣ㡬㒊ࡢ⭾ᙇࢆకࡗ࡚⁐ᒾࡀᒣ㡬ⅆཱྀ ฟ⌧ࡋࡓࠋ12 ᭶ᮎࡽ⁐ᒾᔂⴠక࠺ⅆ○ὶࡀⓎ⏕ࡋጞࡵ㸪⁐ᒾࢻ࣮࣒ࡣᡂ㛗⥆ࡅ㸪ḟ➨ ༡ᮾᩳ㠃ᡂ㛗ࢆ⥆ࡅ⁐ᒾὶ࡞ࡾ㸪Ỉᖹ㊥㞳࡛㛗ࡉ⣙ 3 km 㐩ࡋ㸪ᄇฟ㔞ࡣ 0.13 km3 㐩 ࡋࡓ㸦ᅗ 1㸧 ࠋ2014 ᖺᮎ࡛ࡶ㸪ᙜึࡢໃ࠸ࡣῶࡌࡓࡀ㸪⁐ᒾࡣࡲࡔᡂ㛗ࢆ⥆ࡅ࡚࠸ࡿࠋᄇⅆࡢ ᪉ࡸⅆ○ὶࡢศᕸ⠊ᅖࡣ 9-10 ୡ⣖ᄇⅆࡰྠࡌ࡛࠶ࡿࠋ⁐ᒾࡣᩬᬗᐩࡴゅ㛝▼㍤▼Ᏻ ᒣᒾ㸦SiO2 57-58%㸧࡛࠶ࡿࠋᆅ㉁Ꮫⓗ࡞◊✲࡛ࡣࡇࡢⅆᒣࡢᡂ㛗ྐࢆ㏻ࡋ࡚⇿Ⓨⓗ࡞ᄇⅆࡀ ㉳ࡁ࡚࠸࡞࠸ࡇࢆ♧ࡋ࡚࠸ࡿࠋ ᮾࢪࣕ࣡࠶ࡿࢣ࣮ࣝࢺⅆᒣࡣ⣙ 20 ᖺ࠾ࡁࣉࣜࢽ࣮ᘧࡢᄇⅆ㸦VEI 4㸧ࢆ⧞ࡾ㏉ࡋ࡚࠸ ࡿࠋ2014 ᖺ 2 ᭶ 13 ᪥ࡢኪࣉࣜࢽ࣮ᘧᄇⅆࢆ㛤ጞࡋ㸪⣙ 6 㛫ᚋᄇⅆࡣࡲࡗࡓࠋᄇ↮ ࡣୖ✵ 18-25km 㐩ࡋ㸪ⅆᒣ⅊ࡣⅆᒣࡢすഃ㐲᪉ࡲ࡛ᗈࡃሁ✚ࡋࡓࠋᄇⅆࡢ๓ 2 㐌㛫๓ࡽ ᛴ⃭ᆅ㟈ࡀከⓎࡋ㸪ࡑࡢ㢖ᗘᙉᗘࢆ㛫ࡶቑࡋ࡚ᄇⅆࡋࡓࠋ2007-8 ᖺࡣ㸪ⅆཱྀ ෆ⁐ᒾࢻ࣮࣒㸦⣙ 0.04 km3㸧ࡀᙧᡂࡉࢀࡓࡀ㸪ࡇࡢ⁐ᒾࢻ࣮࣒ࡣᅇࡢᄇⅆ࡛྿ࡁ 㣕ࡤࡉࢀࡓ㸦ᅗ 2㸧ࠋᅇࡢᄇⅆࡢᄇฟ㔞ࡣ 0.2-0.3 km3 ࡛࠶ࡿࠋᄇⅆࡋࡓ㍍▼ࡣ⤖ᬗᐩࡴ㍤ ▼Ᏻᒣᒾ㸦SiO2 55~56%㸧࡛࠶ࡿࠋᒾ▼Ꮫⓗ≉ᚩࡣ 2007-2008 ᖺ⁐ᒾ㓞ఝࡋ࡚࠸ࡿࠋ 2013~2014 ᖺࢩࢼࣈࣥⅆᒣࢣ࣮ࣝࢺⅆᒣ࡛㉳ࡁࡓᄇⅆࡣ㸪㠀⇿Ⓨⓗᄇⅆ⇿Ⓨⓗᄇⅆ ࡢዲ࡛࠶ࡿࠋᄇⅆࡢつᶍࡣ࣮࢜ࢲ࣮࡛ࡣྠࡌ࡛࠶ࡾ㸪࣐ࢢ࣐⤌ᡂࡶࡁࡃ㐪ࢃ࡞࠸ࠋ࣐ࢢ ࣐ࡢ✚῝ᗘࡸ᥎ᐃࡉࢀࡿỈࡢ㔞ࡶⰋࡃఝ࡚࠸ࡿ⪃࠼ࡽࢀࡿࠋࡋࡋ㸪ᄇฟ⋡ࡣ୧⪅࡛ ࡁࡃ␗࡞ࡾ㸪ࢩࢼࣈࣥⅆᒣ࡛ 5m3/s ࡛࠶ࡿࡢᑐࡋࢣ࣮ࣝࢺⅆᒣ࡛ࡣ 2~3 m3/s ࡛࠶ࡿ㸦ᅗ 3㸧ࠋ୍᪉࡛㸪ࢣ࣮ࣝࢺⅆᒣ࡛ࡣࡇࡢ㸴ᖺ㛫⤌ᡂࡀྠࡌ࣐ࢢ࣐ࡀ⁐ᒾࢻ࣮࣒ᄇⅆࣉࣜࢽ࣮ ᘧᄇⅆࢆ㉳ࡋ࡚࠸ࡿࠋࢩࢼࣈࣥⅆᒣࢣ࣮ࣝࢺⅆᒣ㸪࠶ࡿ࠸ࡣࢣ࣮ࣝࢺⅆᒣࡔࡅ࡛ࡶ㸪␗࡞ ࡿࢱࣉࡢᄇⅆࡀ␗࡞ࡿᄇฟ⋡࡛ᘬࡁ㉳ࡇࡉࢀࡓࠋ Fig. 1. Lava flow on the southeastern slope of Sinabung volcano (left: night view in Jan. 2014) and ash-cloud of pyroclastic flow of the Feb. 1, 2014 event (right). The latter was taken by CVGHM ᅗ 1 ࢩࢼࣈࣥⅆᒣࡢ༡ᮾᩳ㠃ࡢ⁐ᒾὶ㸦ᕥࠋ2014 ᖺ 1 ᭶ࡢኪᬒ㸧 2014 ᖺ 2 ᭶ 1 ᪥ⅆ○ ὶ㸦ྑࠋࣥࢻࢿࢩⅆᒣᆅ㉁⅏ᐖ㍍ῶࢭࣥࢱ࣮ᥦ౪㸧 - 49 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 Fig. 2. Crater area of Kelud volcano. Left: after the Feb 2014 eruption (Feb. 23, 2014) taken by CVGHM. Right: before the eruption (Dec. 8, 2008). ᅗ 2 ࢣ࣮ࣝࢺⅆᒣᄇⅆ๓ᚋࡢⅆཱྀࡢᵝᏊࠋᕥ㸧2014 ᖺ 2 ᭶ 23 ᪥ࠋྑ㸧2008 ᖺ 12 ᭶ 8 ᪥ࠋ Fig. 3 Discharge rate and eruption volume relationship. The original iagram of Kozono et al. (2013) was referred. ᅗ 3 ᄇฟ⋡ᄇฟ㔞㸦⁐ᒾ⟬㸧ࡢ㛵ಀࠋKozono et al. (2013)ࡢཎᅗࢆཧ⪃ࡋࡓࠋ - 50 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 4-02 ࣥࢻࢿࢩࡢⅆᒣᆅᙧ Ᏺᒇ௨ᬛ㞝㸦㔠ἑ࣭ྡᩍᤵ㸧 Volcanic geomorphology of Indonesia I. Moriya (Honorary Prof., Kanazawa Univ.) Sumatra, Java, Bali, Lombok, Sumbawa, Lomblen, Marisa, Banda ㅖᓥ࡞ࡀ㐃࡞ࡿ㛗ࡉ⣙ 1600 km ཬࡪࣥࢻࢿࢩࢫࣥࢲᘼἢ࠺ⅆᒣࡢᴫせࢆ㸪ᆅᙧᅗ࣭Google Earth 3D ⏬ീࡢุ ㄞࡽ᫂ࡽࡋ㸪Ᏺᒇ㸦1979, 1983, 2012㸧ࡋࡓࡀࡗ࡚ศ㢮ࡋࡓ㸬ࡋࡓࡀࡗ࡚ᮏሗ࿌ࡣᆅ ᙧሗ᥇ྲྀࢆయࡍࡿணᐹసᴗ⤖ᯝࡢሗ࿌ࡶ࠸࠼ࡿෆᐜ࡛࠶ࡿࡀ㸪ከࡃࡢ᪂ࡓ࡞ሗࡀ ᚓࡽࢀࡓࡢ࡛㸪ࡇࡇሗ࿌ࡍࡿ㸬ᚋࡉࡽᆅ㉁࣭ᒾ▼࣭ᖺ௦್࡞ࡢሗࢆຍ࠼㸪ࡼࡾ ࡞ᡂᯝࢆᑟࡁࡓ࠸㸬 ࣥࢻࢿࢩ࣭ࢫࣥࢲิᓥࡢⅆᒣ⥲ᩘࡣ 236 ಶ࡛㸪ࡑࡢ࠺ࡕᡂᒙⅆᒣ 180 ಶ㸦76 %㸧㸪࢝ ࣝࢹࣛⅆᒣ 20 ಶ(8 %)㸪⁐ᒾཎ 2 ಶ(0.8 %)㸪༢ᡂⅆᒣ⩌ 34 ಶ㸦14 % ὶ⣠ᒾ㉁⁐ᒾࢻ࣮࣒ⅆ ᒣ 12 ಶ㸪⋞Ṋᒾ㉁ࢫࢥࣜୣ࣭ᑠᴙ≧ⅆᒣ࣭࣐࣮ࣝ 22 ಶ㸧ࡢෆヂ࡞ࡗ࡚࠸ࡿ㸬ࡓࡔࡋᚋ ࢝ࣝࢹࣛⅆᒣࡣ࢝ࣝࢹࣛⅆᒣྵࡵᩘ࠼࡚࠸࡞࠸㸬すኴᖹὒỿࡳ㎸ࡳᖏࡢⅆᒣ⥲ᩘ 940 ಶࡢ ࠺ࡕᡂᒙⅆᒣࡀ 676 ಶ 72 %࡛࠶ࡿࡢᑐࡋ㸪ࢫࣥࢲิᓥࡢᡂᒙⅆᒣࡢ༨ࡵࡿྜࡣ 76 % ࡸࡸ㧗࠸㸬ࡋࡋᓥᘼࡣࡵࡗࡓฟ⌧ࡋ࡞࠸⋞Ṋᒾ㉁࣐ࢢ࣐㉳※ࡢ⁐ᒾཎࡀ 2 ಶࡶᏑᅾ ࡍࡿࡇ㸪⋞Ṋᒾ㉁࣐ࢢ࣐㉳※ࡢࢫࢥࣜୣ࡞ࡢ༢ᡂⅆᒣ⩌ࡀ㸪すኴᖹὒࡢᖹᆒ 9 %ᑐ ࡋ࡚ 14 %㧗࠸ฟ⌧⋡ࢆ♧ࡍࡇࡣὀ┠ࡉࢀࡿ㸬࢝ࣝࢹࣛⅆᒣࡢ 8 %ࡣすኴᖹὒࡢᖹᆒ 7 % ࡃࡽᕪࡀ࡞࠸㸬ᡂᒙⅆᒣࡢⓎ㐩ࡣ Java ᓥࡢᡂᒙⅆᒣࡢࡳึᮇࡢࡶࡢࡀᑡ࡞ࡃ㸪Sumatra, Flores ᓥ࡞ࡢᡂᒙⅆᒣ࡛ࡣⓎ㐩ึᮇࡢᐩኈᒣᆺࡢࡶࡢࡀከ࠸㸬ᓥᘼࡈⅆᒣᙧᡂ㐜㏿ ࡀ࠶ࡗࡓࡢ㸪Ⓨ㐩㏿ᗘᕪࡀ࠶ࡗࡓࡢ⯆῝࠸㸬 Sumatra ᓥ Java ᓥ࡛ࡣỿࡳ㎸ࡴࣉ࣮ࣞࢺࡢ᪉ྥᕪࡽ㸪Sumatra ᓥ࡛ࡣⅆᒣࡀྑᶓࡎ ࢀ᩿ᒙἢࡗ࡚ 50 km ࡈࡰ㸯ิᓥᘼఙ㛗᪉ྥ୪ࡪࡢᑐࡋ㸪Java ᓥ࡛ࡣ 5-10 ಶ ࡢⅆᒣࡀࡳࡓࡽࡋᅋᏊࡢࡼ࠺࡞ิࢆ࡞ࡋ㸪ᓥᘼఙ㛗᪉ྥ┤ࡋ࡚୪ࡪ㸬࠸ࡢ㊥㞳ࡣ 50100 km ⛬ᗘ࡛㸪20 ิ࠶ࡿ㸬ⅆᒣࡀྠᵝࡢ㓄ิࢆࡍࡿࡣᮾ᪥ᮏᘼ(Tamura et al., 2002) ୰⡿ Costa Rica㸦Ᏺᒇ㸪1999㸧ぢࡽࢀࡿࡔࡅ࡛࠶ࡿ㸬 ᆅᙧᅗุㄞࡽ Sumatra ᓥࡢⅆᒣࡢ୍㒊㸪Java ᓥࡢ㒊ศࡢⅆᒣࡢᆅᙧศ㢮ᅗࡀసᡂࡉࢀ ࡓ㸬ࡑࡢ୍㒊ࢆᥦ♧ࡍࡿࡶ㸪ࡑࢀࡽㄞࡳྲྀࢀࡿࡘ࠸࡚ゎㄝࡍࡿ㸬 - 51 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 Fig.1 Distribution of the volcanoes in Java Is. Note the chains of the volcanoes! Fig.2 Northern half of Danoe caldera volcano Fig.3 Kendeng caldera volcano - 52 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 4-03 Volcanic history and geothermal activity in Dieng geothermal field, central Java, Indonesia A. Harijoko and W. Warmada (Gadjah Mada Univ.) The Dieng Volcanic Complex (DVC), in the Central part of Java Island, is characterized by a collapse structure containing 17 post intra-caldera eruptive centers. This volcanic complex shows long-term volcanic activity of about 3 M.y. and is possibly record the long-term magma evolution at a single volcanic complex. The volcanic edifices in DVC can be grouped into three stages, namely pre-caldera (~3 Ma), post-caldera I (~2 to 1 Ma) and post-caldera II (< 1 Ma). Major element rock compositions suggest that the DVC magma cyclically evolved from basaltic to dacitic composition. Both pre-caldera and post-caldera I have a wide range of composition from basalt to dacite, in contrast the post-caldera II ranges from andesite to dacite. Phenocryst assemblage of all the stage show similar composition including plagioclase, clinopyroxene, orthopyroxene, olivine and magnetite. The post-caldera II lava also contain biotite phenocrysts and are richer in groundmass glass. The increase of silica content is followed by increasing potassium content (K57.5) so that we can distinguish medium-K and high-K magmatism in early andlate stage of each group in pre- and post-caldera. Harker diagrams indicate that magma in DVC is differentiating from the same magma source. Chondrite normalized incompatible element plots show similar patterns among for all edifices, and are typical of the island arc compositions, with enrichment of LILE and LREE compared to HSFE and HREE. Ta/Nb and Zr/Nb ratios of the lava from all stages are similar and range from 0.04 to 0.1 and 16 to 37, respectively, indicating that the mantle composition beneath DVC is still the same and resembles the ratio of Indian MORB. Ce/Pb and Th/Yb ratios indicate the contribution of continental material either as crustal contamination during the passage of magma to surface or sediment influx during partial melting. There are no significant geochemical differences among magmas at DVC. (from the abstract of Proceedings World Geothermal Congress 2010 ) - 53 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 5-01 Geology and crisis management of Pinatubo volcano, central Luzon, Philippines C. Newhall (Mirisbiris Garden and Nature Center, formerly with USGS, NTU/EOS) [email protected] Pinatubo Volcano produced a low-end VEI 6 eruption (~5 km3 DRE of dacitic magma) on June 15, 1991, and developed a 2.5 km diameter caldera the same day. These events were the climax after precursory intrusion of basaltic magma into the dacite reservoir, small phreatic explosions on April 2, magma mixing and eruption days thereafter of a hybrid andesite lava dome on June 7, and three days of conduitclearing VEI 3 eruptions from June 12-14. As seen from the Total Ozone Mapping Spectrometer (TOMS), the eruption injected a very large amount of SO2 (17 Mt) that had accumulated as a discrete bubble phase in the reservoir over preceding centuries – probably a prerequisite for such large eruptions. Modern Pinatubo had a long history of similar or larger dacitic eruptions, and associated hybrid andesite domes. The largest of these – the Inararo eruption – was also the first (originally found to be >35 ka, later determined to be 81 ka from deep sea cores). An Ancestral andesitic Pinatubo had been active over ~ 1 ma prior to that time, and its remaining deposits are much more indurated than those of the Modern Pinatubo. Based on hasty reconnaissance stratigraphy (from air photos and on the ground) and gas-line radiocarbon dates that hadn’t even stabilized, we judged that Pinatubo had repose periods in the order of 1000 years, some longer, some shorter, and that the unrest of 1991 might lead to an eruption similar to those which occurred previously, especially the latest, 400 y BP Buag eruption. On that basis, we forecast that IF Pinatubo would erupt, the eruption would likely be large (e.g., VEI 6), and hazard zones were drawn accordingly. The scientific response to the crisis was managed by the Philippine Institute of Volcanology and Seismology (PHIVOLCS), led by the late Ray Punongbayan. Assistance Program (VDAP) assisted. The USGS’ Volcano Disaster Mitigation decisions were managed by Philippine civil defense and, on the US bases, by US military commanders. Public skepticism was high, public understanding was low, and we scientists used every tool we could to get people ready: hazard maps; personal, group, and community briefings; videos for these briefings and for broadcast TV; talks to schoolchildren and science teachers; probability trees; a numerical alert level scheme; “translation” help from nuns and pastors, and more. We did not exaggerate the threat, but we did speak frankly and urgently. - 54 - The ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 volcano helped us by ramping up both its geophysical and geochemical precursors from June 3-14 and its visible activity on June 12-14. The highest risk areas were evacuated before the climactic eruption. Scientific colleagues in Japan will appreciate the irony of the June 3 increase in activity. On that date in Japan, Maurice and Katia Krafft were trying to collect better pyroclastic flow footage at Unzen, and miscalculated their own risk. On that same date in the US, a colleague and I had to use the Krafft/ IAVCEI video to convince US military commanders in Hawaii of the seriousness of the threat to Clark Air Base in the Philippines. When we briefed the military commanders, we told them that the film- makers (Kraffts) had just been killed by the same phenomenon – a pyroclastic flow – that we feared could strike Clark Air Base. They listened well, and evacuated. An important lesson for stratigraphers and for crisis managers is that the precursors to this exceptionally large explosive eruption were absolutely UNREMARKABLE until the last 24 hours before the climax, i.e., on June 14. Our forecasts of a “worst case” VEI 6 event were based on the geologic record. We were watching closely for geophysical or geochemical indications of an exceptionally large eruption, and it was not until June 14 that the number and energy of shallow low-frequency earthquakes went “off-scale,” well beyond precursors of small eruptions. In other words, it was not until June 14 that the tapping of gas-charged magma became a “runaway” process that would not stop until the gas-rich top of the magma reservoir was exhausted. Fortunately, most communities were already evacuated by that time; it would have been too late to adjust evacuations based on that late seismicity. Another important lesson for hazard assessment is that in some cases, as at Pinatubo, large explosive eruptions are so prevalent that it makes sense to use a “worst case scenario” for evacuation planning. This might not be true where the largest events are relatively rare, but it was true at Pinatubo. Fortunately for Clark Air Base and Angeles City, an even worse case – an even larger eruption – that we discovered after June 15 did not materialize. We thought we had warned of a worst case, but learned later that even worse might have occurred. In the end, most of the 400 eruption-related fatalities were from roofs that collapsed from rain-soaked ashfall. Coincidence of Typhoon Yunya with the climactic eruption was especially unfortunate, as people outside the original evacuation zones naturally wanted to stay in their own homes or under other roofs to avoid both rain and ashfall. Poorly supported roofs collapsed under 10 cm of wet ash. At a volcano known to produce large pyroclastic flows, that hazard gets first attention and it is common for - 55 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ashfall (and lahars) to be consider only later, sometimes too late. The large amount of loose pyroclastic debris on the slopes, and torrential typhoon rains with up to 750 mm/24 hours, conspired to send many lahars – from 10’s to >100 million m3 – into lowland farms and towns. Over the succeeding decade, roughly 60% of the deposit on the volcano slopes was washed down into surrounding lowlands, burying some towns completely. Several hundred people died from lahars, most because they got poor advice and thought they were safe when they were not. Scientific advice re: lahars of Pinatubo was generally excellent; the main problems came from non-scientific misinformation. Tephra fall layers are not well preserved at Pinatubo. them as marker horizons. In fact, we found so few that we could not use Perhaps with more careful work along ridge crests and in special environments like long-lived lakes it might be possible, but in our rapid reconnaissance we worked mainly in river valleys and thus with flow deposits. We used mainly the Fe-Mg mineralogy (all dacites have hornblende; some also have biotite) and radio-carbon ages to establish correlations. There was an optimal period – roughly, in years 2-5 after the eruption – in which incision through the toes of pyroclastic fans and the heads of alluvial fans was greatest, all the way down to ancestral Pinatubo deposits. Stratigraphers should be ready to jump into action to capture outcrops at their maximum exposure. Vegetation had not yet covered the outcrops, nor had aggradation re-buried those outcrops. The tephra story merits further study, and might still be accessible, especially with new roads up interfluves on most sides of the volcano. There were also many opportunities – spread over a decade – to witness active processes including pyroclastic flows; secondary (rootless) explosions and secondary pyroclastic flows; lahars of all kinds; dome growth; and creation, filling, and breaching of a small caldera lake. In most cases, we could study deposits shortly after the events, and also correlate them to geophysical and geochemical signatures in monitoring data. An eruption like Pinatubo is a wonderful opportunity for those who work on older deposits to learn the complex details of events that can be lost from the geologic record. Specifically, in the valleys, there was so much cut and fill activity that the final deposits represented only the latest and/or largest events, with many more intermediate events lost from the geologic record. Lahars from single typhoons can scour down tens of meters and then backfill (aggrade) by the same or more! - 56 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 Indigenous people of Pinatubo, the Aytas, were at special risk. Most of them were saved by timely evacuations, except for one group that sought shelter in a cave close to the volcano. About 500 Ayta children died from measles in evacuation centers because their parents distrusted lowland doctors and could no longer collect traditional plant medicines from Pinatubo. brought many changes to the Ayta culture, both good and bad. The eruption and its aftermath A researcher from Kyushu University, Hiromu Shimizu, has published on the effects of Pinatubo on the Aytas. Volcanologists from the Philippines, US, and many other countries including Japan, and a few social scientists from the Philippines, described the eruption, its precursors, its lahars, and its immediate physical effects on the surroundings in a 1996 monograph titled “Fire and Mud: Eruptions and lahars of Mount Pinatubo, Philippines. This can still be found in used bookstores, and it is freely accessible online at http://pubs.usgs.gov/pinatubo. - 57 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 5-02 ࣇࣜࣆࣥࡢࣆࢼࢶ࣎ⅆᒣᒣ㡬࢝ࣝࢹࣛ†࿘㎶ࡢ ⇕࣑ࣝࢿࢵࢭࣥࢫ(TL)ᖺ௦ 㧗ᓥ ࣭すᕝ 㸦⛅⏣㸧࣭ᑠᯘဴኵ㸦㮵ඣᓥ㸧࣭ዟ㔝 㸦⚟ᒸ㸧 Thermoluminescence㸦TL㸧age of rocks from summit caldera lake at Pinatubo volcano, Luzon Island, Philippines I. Takashima, O. Nishikawa (Akita Univ.), T. Kobayashi (Kagoshima Univ.) and M. Okuno (Fukuoka Univ.) ࣇࣜࣆࣥඹᅜࣝࢯࣥᓥ୰㒊࠶ࡿࣆࢼࢶ࣎ⅆᒣࡣ 1991 ᖺᄇⅆࢆ㉳ࡇࡋ㸪ᒣ㡬㒊 ࢝ࣝࢹࣛ†ࢆ⏕ࡌ࡚࠸ࡿ㸬ࡇࡢ࢝ࣝࢹࣛ࿘㎶ࡣ㸪᭱᪂ᮇࡢᄇⅆάືࡼࡿࢻ࣮࣒⁐ᒾࡸⅆ ○ὶࡀศᕸࡋ࡚࠾ࡾ㸪άືྐࡢඖ㔜せ࡛࠶ࡿ㸬᪂ᮇࡢⅆᒣάືࡣᒣ㯄ࡢⅆ○ሁ✚≀ࡢ㸯㸲 C ᖺ௦ ᐃࡽ㸪35kaBP, 17kaBP, 9kaBP, 6-5kaBP, 3.9-2.3kaBP ࠾ࡼࡧ 0.5kaBP ࠸࠺άື ᖺ௦ࡀሗ࿌ࡉࢀ࡚࠸ࡿ 㸦Newhall et al., 1996㸧㸬ࡲࡓ㸪ᒣ㡬㒊ࡢᒾయࡘ࠸࡚ࡶ⇕࣑ࣝࢿࢵࢭ ࣥࢫ㸦TL㸧ἲࡼࡾ┤᥋ ᐃࡀ⾜ࢃࢀ㸪20ka㸪9ka㸪6-5ka ࠸࠺ᖺ௦ࡀᚓࡽࢀ࡚࠸ࡿ㸦ᏲᏳ 㸪2007㸧 㸬 ᅇ㸪ࡼࡾヲ⣽࡞ᖺ௦ࢆᚓࡿࡓࡵᒣ㡬㒊ࡢ࢝ࣝࢹࣛ†࿘㎶ࡢ 13 ᆅⅬ㸦Fig.1㸧࡛ 24 ಶࡢヨ ᩱࢆ᥇ྲྀࡋ㸪TL ᖺ௦ ᐃࢆ㐍ࡵ࡚࠸ࡿ㸬ヨᩱࡣ㸪ゎ㔘ࡀᐜ᫆࡞ࢻ࣮࣒⁐ᒾࢆඃඛࡋ࡚᥇ྲྀࡋ ࡓࡀ㸪†ᡂሁ✚≀ࡸᔂቯሁ✚≀୰ࡢ⁐ᒾ∦ࡶྵࡲࢀ࡚࠸ࡿ㸬TL ᖺ௦ࢆ☜ᐃࡍࡿࡓࡵࡣ㸪ᆅ ㉁௦ཷࡅࡓᨺᑕ⥺㔞㸦ࣃࣞ࢜ࢻ࣮ࢫ㸪PD㸧㸯ᖺ㛫ヨᩱࡀཷࡅࡿ⥺㔞㸦ᖺ㛫⥺㔞㸪AD㸧 ࡢ᪉ࡢ ᐃࡀᚲせ࡛࠶ࡿ㸬ᚋ⪅ࡘ࠸࡚ࡣ㸪ᨺᑕ ᛶඖ⣲࡛࠶ࡿ U㸪Th㸪K㸦K2O㸧ࡢᒾ ᐃࡽồࡵ ࡿࡇࡀ࡛ࡁ㸪Ȗ ⥺ࢫ࣌ࢡࢺ࣓ࣟࢺ࣮ࣜἲࡼࡾࡍ ࡛⟬ᐃࡉࢀ࡚࠸ࡿ㸬୍᪉ࠊPD ࡘ࠸࡚ࡣ㸪ேᕤⓗ ࡞ᨺᑕ⥺↷ᑕ㸦Ȗ ⥺㸧ࡼࡾồࡵࡿࡇࡀᚲせ࡛࠶ ࡾ㸪ṇ☜࡞ホ౯ࡣ」ᩘࡢ␗࡞ࡗࡓ⥺㔞ࡢ↷ᑕࡀ⾜ ࢃࢀࡿ㸬⌧ᅾࡣ୍㒊ࡢヨᩱࡘ࠸࡚㸪㸯Ⅼࡢࡳࡢ↷ ᑕࢹ࣮ࢱ࡛ᴫ␎ࡢᖺ௦ࢆồࡵ࡚࠸ࡿ㸦Table㸯㸧 㸬ࡑࡢ ⤖ᯝࡣ㸪୍㒊ࢆ㝖࠸࡚ࡇࢀࡲ࡛ࡢࢹ࣮ࢱ㏆࠸್ ࡞ࡗ࡚࠸ࡿࡀ㸪⢭ᗘࡣࡃຎࡗ࡚࠸ࡿ㸬ᚋ㸪Ȗ ⥺↷ ᑕࢆቑࡸࡋ࡚ ᐃࡍࡿࡇ࡛⢭ᗘࡢ㧗࠸ᖺ௦ࡀồࡵ - 58 - Fig. 1 Location of TL samples. ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡽࢀࡿ㸬࡞࠾㸪ᖺ௦ࡣ┤᥋ࡢ㛵ಀࡣ࡞࠸ࡀ㸪ᆅⅬ㸲㸪㸳㸪㸴࡛ࡣ U ྵ᭷㔞ࡀ␗ᖖ㧗࠸ヨ ᩱࡀㄆࡵࡽࢀࡿ㸦୍⯡㸪ⅆᒣᒾ୰ࡢ U㸸Th ࡣ㸯㸸㸱⛬ᗘ㸧 㸬ࡇࢀࡽࡢᒾ▼ࡣ㸪㏻ᖖࡣ␗࡞ ࡿ࣐ࢢ࣐ศࡀᐃࡉࢀ㸪ࡑࡢ㠃ࡽࡢ᳨ウࡀᮇᚅࡉࢀࡿ㸬 Table 1 Preliminary TL age data of Pinatubo Volcano. 㸦ᩥ⊩㸧Newhall et al. (1966) in Fire and mud, 165-195. ᏲᏳ㸦2007㸧ᆅ㉁Ꮫ 115 ᖺᏛ⾡ㅮ₇せ᪨㸪O-51. - 59 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 5-03 Radiocarbon dating of wood trunks from crater wall of Pinatubo volcano, Luzon Island, Philippines M. Okuno (Fukuoka Univ.), T. Nakamura (Nagoya Univ.), E. Bariso, M.T. Quilalang, A. Daag (PHIVOLCS) and T. Kobayashi (Kagoshima Univ.) The summit crater of Pinatubo volcano was formed by the calderagenic eruption of 1991 (Newhall and Punongbayan, 1996). At eastern wall of the crater, wood trunks are embedded in lacustrine deposit. The lacustrine block fell directly from the wall were found at foot slope (Fig. 1). We conducted radiocarbon (14C) dating of wood trunks with accelerator mass spectrometer (AMS) at Nagoya University. The obtained dates of 3770s50 BP and 3550s50 BP corresponds to ca. 4 cal kBP (Table 1). The two ages do not agree beyond the error range. Therefore, these samples may be from different horizons. However, wood trunks are found from only one horizon. These dates are almost consistent with dates in Maraunot period (Newhall et al., 1996). From the age of lacustrine deposit, it indicates that crater lake was formed by the eruptions during Maraunot period, which shows similar pattern from the 1991 Pinatubo eruption that formed the present crater. ࣆࢼࢶ࣎ⅆᒣࡢᒣ㡬ⅆཱྀࡣ㸪1991 ᖺࡢᄇⅆ࡛ᙧᡂࡉࢀࡓ㸦Newhall and Punongbayan, 1996㸧 㸬 ⅆཱྀᮾ㒊ᓴ㟢ฟࡋ࡚࠸ࡿ†ᡂᒙ୰ࡣᮦ▼ࡀྵࡲࢀ࡚࠸ࡿ㸬₇⪅ࡽࡣⅆཱྀෆᔂⴠࡋࡓ ࣈࣟࢵࢡ୰ࡢᮦ▼㸦Fig. 1㸧ࡢᨺᑕᛶⅣ⣲㸦14C㸧ᖺ௦ࢆ ᐃࡋࡓࡢ࡛㸪ࡇࡢ⤖ᯝࢆሗ࿌ࡍࡿ㸬 14 C ⃰ᗘ ᐃࡣ㸪ྡྂᒇᏛࡢຍ㏿ჾ㉁㔞ศᯒ㸦AMS㸧ィࢆ⏝࠸ࡓ㸬ᚓࡽࢀࡓᖺ௦ࡣ㸪3770 s50 BP 3550s50 BP ࡛㸪ᬺᖺ㍑ṇࡢ⤖ᯝ㸪ࡇࢀࡽࡣ⣙ 4 cal kBP ࡢᬺᖺ௦┦ᙜࡍࡿ㸦Table 1㸧 㸬㸰ࡘࡢᖺ௦್ࡣㄗᕪ⠊ᅖࢆ㉸࠼୍࡚⮴ࡋ࡞࠸ࡓࡵ㸪␗࡞ࡿᒙ‽⏤᮶ࡍࡿྍ⬟ᛶࡀ࠶ࡿ㸬 - 60 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡑࡢᚋ㸪ⅆཱྀෆቨ㟢ฟࡍࡿ†ᡂᒙࢆほᐹࡋࡓ⤖ᯝ㸪ᮦ▼ࡀ⏘ࡍࡿᒙ‽ࡣࡦࡘࡋ☜ㄆ ࡛ࡁ࡞࠸㸦Fig. 2㸧 㸬ࡑࡢࡓࡵ㸪ᔂⴠࣈࣟࢵࢡࡶࡑࡢᒙ‽⏤᮶ࡍࡿ⪃࠼ࡽࢀࡿ㸬ᅇࡢᖺ௦ ࡣ㸪Maraunot ᮇࡢࡶࡢ㸦Newhall et al., 1996㸧ᴫࡡ୍⮴ࡋ࡚࠾ࡾ㸪ࡇࡢᮇࡢᄇⅆ࡛⌧ᅾࡢ ࡼ࠺ⅆཱྀ†ࡀ࠶ࡿᮇ㛫Ꮡᅾࡋ࡚࠸ࡓࡇࢆ♧ࡍ㸬 Fig. 1 Table 1 Photo showing occurrence of wood trunks in lacustrine block. Radiocarbon dates from wood fragments in lacustrine at summit crater of Pinatubo volcano - 61 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 5-04 ࣃࢱࣥ†ࡢ࣮࣎ࣜࣥࢢ᥀๐(㏿ሗ) 㫽┿அ(⇃ᮏ)࣭E. Bariso࣭D.J. Rivera࣭R. Lim࣭C. Pogay࣭A. Daag (PHIVOLCS)࣭ ᒣᓮᆂ࣭୰す࣭ዟ㔝 (⚟ᒸ) Boring cored sediments from Paitan Lake, central Luzon, Philippines M. Torii (Kumamoto Univ.), E. Bariso, D. J. Rivera, R. Lim, C. Pogay, A. Daag (PHIVOLCS), K. Yamasaki, T. Nakanishi and M. Okuno (Fukuoka Univ.) ᪥ᮏྠᵝᩘከࡃࡢάⅆᒣࢆ᭷ࡍࡿࣇࣜࣆࣥඹᅜ࡛ࡣ㸪ᚎࠎ࡛ࡣ࠶ࡿࡀྛⅆᒣࡈ ᄇⅆྐ◊✲ࡀ࠾ࡇ࡞ࢃࢀࡘࡘ࠶ࡿ㸬ࡋࡋ㸪ᒙᗎࡢᇶ‽࡞ࡿᗈᇦࢸࣇࣛࡢᏑᅾࡀㄆ㆑ࡉࢀ ࡚࠸࡞ࡗࡓࡇࡽ㸪ṇ☜࡞ᒙ㛵ಀᇶ࡙ࡃⅆᒣάືࡢᢕᥱࡀᅔ㞴࡛࠶ࡗࡓ㸬㏆ᖺ㸪ࣝ ࢯࣥᓥ༡ᮾ➃ࣟࢩࣥ㸦Irosin㸧࢝ࣝࢹࣛࢆᙧᡂࡋࡓつᶍⅆ○ὶᄇⅆ(41 cal kBP)࠾࠸࡚㸪 㝆ୗⅆᒣ⅊㸦co-ignimbrite ash-falls㸧ࡢᏑᅾࡀ᫂ࡽࡉࢀ㸪ࣇࣜࣆࣥ࠾ࡅࡿᗈᇦᑐẚࡢ 㘽ᒙ࡞ࡾᚓࡿྍ⬟ᛶࡀ♧ࡉࢀࡓ( Mirabueno et al., 2011)㸬ࡇࡢࡼ࠺࡞㘽ᒙ࡞ࡾᚓࡿࢸࣇࣛ ࡢ࢝ࢱࣟࢢࡣࡇࡢᆅᇦࡢⅆᒣᏛࡁࡃᐤࡍࡿࡇࡽ㸪ࣟࢩࣥᄇⅆ௨㝆ࡢ㧗⢭ᗘࢸ ࣇࣛ࢝ࢱࣟࢢࡢᵓ⠏ࢆᙜ㠃ࡢ┠ᶆࡋࣟࢩࣥ࢝ࣝࢹࣛ࿘㎶ࡢ㸱ࢧࢺ࡛࣮࣎ࣜࣥࢢㄪᰝࢆ ࠾ࡇ࡞ࡗ࡚ࡁࡓ㸬ࡋࡋ㸪ࢸࣇࣛಖᏑᛶࡢࡼ࠸†ᡂᒙࡢᏑᅾࢆᮇᚅࡋࡓ࢝ࣝࢹࣛෆࡢ࣮࣎ࣜ ࣥࢢㄪᰝ࡛ࡣ㸪⤖ᯝࡋ࡚Ἑᕝᡂࡢሁ✚≀ࣈࣝࢧࣥⅆᒣ㉳※ࡢࣛࣁ࣮ࣝሁ✚≀ࢆయࡋ ࡚࠾ࡾ㸪ࢸࣇࣛࡣⅆ○ὶሁ✚≀ 1 ᒙ㝆ୗࢸࣇࣛ 12 ᒙࢆぢ࠸ฟࡋࡓࡢࡳ࡛㸪ᗈᇦࢸࣇࣛࡢ≉ ᚩࢆ♧ࡍࢸࣇࣛࡢⓎぢࡣฟ᮶࡚࠸࡞࠸㸦Mirabueno et al., 2014㸧㸬ࡑࡇ࡛ᅇࡣ᥀๐ㄪᰝࡢᑐ㇟ ࢆ㟼࡞ሁ✚⎔ቃࡀ᥎ᐃࡉࢀࡿࣃࢱࣥ†ࡢ†ᡂᒙࢱ࣮ࢤࢵࢺࢆኚ᭦ࡋ 2015 ᖺ 1 ᭶ᮎࡼ ࡾ᥀๐ࢆ㛤ጞࡋࡓ㸬ࣃࢱࣥ†ࡣᙧࢡ࣮ࣞࢱ࣮≧ࡢᆅᙧ࣒ࣜࢆᙧᡂࡍࡿࢧ࣮ࢪሁ✚≀ࡢ Ꮡᅾࡽࢱࣇࣜࣥࢢ᥎ᐃࡉࢀࡿ㸬⌧ᅾ㸪ࢱࣇࣜࣥࢢ୰ᚰ㏆ࡢࡳࡀ‣Ỉࡋ࡚࠾ࡾ㸪࣒ࣜෆ ഃᩳ㠃ࡣỈ⏣ࡀᙧᡂࡉࢀ࡚࠸ࡿ㸬†ࡣഃᖜᩘ m ࡢᑠᕝࡀ࠶ࡿࡢࡳ࡛ᐇୖ†ὶධ ࡍࡿἙᕝࡣ࡞࠸ࡇࡽ㸪ὥỈࡼࡿሁ✚≀ࡢኚࡣẚ㍑ⓗ㍍ᚤ࡞ࡶࡢᛮࢃࢀࡿ㸬ᐇ㝿㸪 ᳜≀⌛㓟యศᯒࢆ┠ⓗࡋࡓྜྷ⏣(2011)࡛ࡣ㸪ᡭືᘧࣆࢫࢺ࣭ࣥ ࢧࣥࣉ࣮ࣛࢆ⏝࠸ 240cm ࡢヨᩱ᥇ྲྀࢆ࠾ࡇ࡞࠸㸪ᒙ‽ࡀࢩࣝࢺ࡛࠶ࡿࡇࢆ♧ࡋ࡚࠾ࡾ㸪᭱ୗ㒊㏆ࡢᖺ௦ࡀࡼࡑ 2,500 ᖺ๓࡛࠶ࡿࡇࡶሗ࿌ࡋ࡚࠸ࡿ㸬Fujiki et al.(2013)࡛ࡣⰼ⢊᥇ྲྀࡢࡓࡵ⾜ࡗࡓࣁࣥࢻ ࣮࣮࢜࢞ࡼࡿ᥇ྲྀ࡛⣙ 300cm ࡢヨᩱࢆᚓ࡚࠾ࡾ㸪ྠᵝᒙ‽ࡀࢩࣝࢺ࡛࠶ࡿࡇ㸪῝ᗘ 278cm ࡛⣙ 1,200 cal BP ࡛࠶ࡿࡇࢆ♧ࡋ࡚࠸ࡿ㸬 ᥀๐ᆅⅬࡣ†ࡢ୰ᚰ࡛ࡁࡿ㝈ࡾ㏆࠸ᆅ Ⅼࡋ࡚༡ᮾഃࢆ㑅ᐃࡋ㸪50m ࡢணᐃ࡛᥀๐ࢆ㛤ጞࡋࡓ㸬2 ᭶ 6 ᪥⌧ᅾ῝ᗘ 27m ࡲ࡛ SPT - 62 - ⚟ᒸᏛᅜ㝿ⅆᒣᄇⅆྐሗ◊✲ᡤ ㅜ എ◊✲㞟࡞ࡽࡧ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟 ㅮ₇せ᪨㞟 ࡼࡾ᥀๐ࡀ㐍⾜ࡋ࡚࠸ࡿ㸬᥇ྲྀࡉࢀࡓࢥࡣඛ⾜◊✲ྠᵝ㒊ศࡀࢩࣝࢺࡽ࡞ࡾ㸪ᬯ⅊ Ⰽࡽ㯮Ⰽࢆ࿊ࡋ㸪ࡲࡓ᪤」ᩘᒙ‽࡛ࢸࣇࣛᒙࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸬ᮏㅮ₇࡛ࡣ᥀๐ࡢ≧ἣ ࢆ⤂ࡍࡿ㸬 Fig.1 ⨨ᅗ Fig.2 ࣃࢱࣥ†᥀๐ࢧࢺ⨨ (google map ࡼࡿ) - 63 - 《 メ モ 》