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こちら - ACRIFIS-EHAI
ᅦ‫׎ܖٻޢ‬ᨥ້‫້֩ޛ‬Ӫऴ‫إ‬ᄂᆮ৑‒
ᇹ ‧ ‫ׅ‬ᄂᆮᨼ˟↙↸↢↚‒
ᇹ ‫ ‒ׅ ‫‬ᙱଐஜ້‫෇ޛ‬ѣᄂᆮᨼ˟‒
ᜒ๫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
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ ➨ ᅇ◊✲㞟఍࡞ࡽࡧ࡟
➨ ᅇ す᪥ᮏⅆᒣάື◊✲㞟఍ ࣉࣟࢢ࣒ࣛ
᪥⛬㸸2015 ᖺ 2 ᭶ 7 ᪥㸦ᅵ㸧ࠥ8 ᪥㸦᪥㸧
఍ሙ㸸⚟ᒸ኱Ꮫ୐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㝆ୗࢫࢥࣜ࢔ࡢ
౛ࠖ
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
ࠕ஑ᕞࡢⅆᒣࣇࣟࣥࢺ࡟࠾ࡅࡿ࣐ࢢ࣐⏕ᡂࣉࣟࢭࢫ㹼࣓ࣝࢺໟ᭷
≀࠿ࡽࡢ࢔ࣉ࣮ࣟࢳ㹼ࠖ
1-03 ⏣ᓥ㟹ஂ㸦᪥ᮏᕤႠ㸧
ࠕ㟝ᓥⅆᒣ⩌㸪⏋ᓅⅆᒣࡢⓎ㐩ྐ̿」ᡂⅆᒣࡢ㢮ᆺ໬࡟ྥࡅ̿ࠖ
㸦ఇ ᠁㸧14:10 – 14:20
1-04 ⟄஭ṇ᫂㸦ࢲ࢖ࣖࢥࣥࢧࣝࢱࣥࢺ㸧࣭ᑠᯘဴኵ㸦㮵ඣᓥ኱㸧
ࠕ㟝ᓥⅆᒣ⩌㸪ᚚ㖊ⅆᒣ࡟࠾ࡅࡿ࢔ࢢࣝࢳࢿ࣮ࢺ࡜ⅆ○ὶࠖ
1-05 ᡂᑿⱥோ㸦Ṋᒸྎ㧗㸧
ࠕᖾᒇⅆ○ὶ࡟ࡼࡿᆅᒙࡢᶓ㌿⌧㇟ࠖ
1-06 ᆏཱྀ ᕦ࣭ᰆཎ㞞ᶞ࣭ᒣᓮᆂ஧࣭ዟ㔝 ඘㸦⚟ᒸ኱㸧
ࠕ⇕࣑ࣝࢿࢵࢭࣥࢫ㸦TL㸧ᖺ௦࠾ࡼࡧ඲ᒾ໬Ꮫ⤌ᡂ࡟ࡼࡿᯇࡢྎ
ᒾᒌ࡞ࡔࢀሁ✚≀ࡢ⤥※᥎ᐃࠖ
ࢭࢵࢩࣙࣥ㸰㸸㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢࡓࡵࡢ᝟ሗᏛ(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᭷ࡢࡓࡵࡢ᝟ሗࢧ࢖ࢺ࡜཰㞟ᨭ᥼ࢶ࣮ࣝࡢ
ᩚഛࠖ
2-03 㧗ᶫఙᘺ࣭ዟᮧ ຾࣭㭯⏣┤அ㸦⚟ᒸ኱㸧
ࠕ◊✲ࢹ࣮ࢱඹ᭷ࡢࡓࡵࡢᆅ⌮᝟ሗࢹ࣮ࢱ࣮࣋ࢫࢧ࣮ࣅࢫࡢᵓ
⠏ࠖ
2-04 㭯⏣┤அ࣭㧗ᶫఙᘺ࣭ዟᮧ ຾㸦⚟ᒸ኱㸧
ࠕⅆᒣᄇⅆྐ᝟ሗࢹ࣮ࢱ࣮࣋ࢫࡢ ḟ฼⏝࡟ࡘ࠸࡚ࠖ
2 ᭶ 8 ᪥㸦᪥㸧
ࢭࢵࢩࣙࣥ㸱㸸࢝ࣝࢹࣛⅆᒣ࡜࢝ࣝࢹࣛᄇⅆ(9:00 – 14:00)
㸦ᗙ㛗㸸୕ᾆ኱ຓ࣭ୗྖಙኵ࣭✄಴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
ࠕ༡஑ᕞ㸪ụ⏣࢝ࣝࢹࣛࡢᄇⅆྐࠖ
3-02 ୗྖಙኵ㸦⏘⥲◊㸧
ࠕጸⰋධᡞⅆ○ὶᄇฟ࡟⮳ࡿ๓㥑ᄇⅆ㐣⛬㸸࣐ࢢ࣐⁀ࡲࡾࡢῶᅽ
㐍⾜ࠖ
3-03 ୕ᾆ኱ຓ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Ἴࢺࣔࢢࣛࣇ࢕࣮࠿ࡽ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ኚ໬ࠖ
㸦᫨ 㣗㸧12:10 – 13:00
3-06 ᑠᯘဴኵ㸦㮵ඣᓥ኱㸧࣭ᡂᑿⱥோ㸦Ṋᒸྎ㧗㸧
ࠕ㨣⏺࢝ࣝࢹࣛࡢ࢔࢝࣍ࣖᄇⅆࠖ
3-07 ዟ㔝 ඘㸦⚟ᒸ኱㸧
ࠕᱜᓥⅆᒣࡢᄇⅆྐ࠿ࡽࡳࡓ⸃ᦶᄇⅆࡢྍ⬟ᛶࠖ
3-08 ⏣ཱྀᖾὒ㸦⚟ᒸ኱㸧
ࠕᆅ⊹ࡸ Ἠᆅᇦ࡟ㄆࡵࡽࢀࡿ㧗 㓟ᛶࡢⅆᒣᛶὶయࡢྡṧࡾࠖ
3-09 Ώ㑓බ୍㑻㸦஑ᕞ኱㸧
ࠕⅆᒣάືึᮇࡢࢸࣇࣛࢆ౑ࡗࡓᒾ▼Ꮫⓗࣔࢽࢱࣜࣥࢢʊࢭࣥ
ࢺ࣊ࣞࣥࢬⅆᒣ 1980 ࡢ౛࣮ࠖ
ࢭࢵࢩࣙࣥ㸲㸸࢖ࣥࢻࢿࢩ࢔ࡢⅆᒣ(14:10 – 15:30)
㸦ᗙ㛗㸸⏣ཱྀᖾὒ㸧
4-01 ୰⏣⠇ஓ㸦ᮾி኱㸧
࣭ྜྷᮏ඘ᏹ㸦ᐩኈⅆᒣ◊㸧࣭๓㔝 ῝㸦ᮾ
ி኱㸧࣭஭ཱྀṇே㸦ி㒔኱㸧
ࠕ࢖ࣥࢻࢿࢩ࢔㸪ࢩࢼࣈࣥⅆᒣ࡜ࢣ࣮ࣝࢺⅆᒣࡢᄇⅆࠖ
4-02 Ᏺᒇ௨ᬛ㞝㸦㔠ἑ኱࣭ྡ㄃ᩍᤵ㸧
ࠕ࢖ࣥࢻࢿࢩ࢔ࡢⅆᒣᆅᙧࠖ
4-03 Agung Harijoko and Wayan Warmada
ࠕVolcanic history and geothermal activity in Dieng geothermal field,
central Java, Indonesiaࠖ
ࢭࢵࢩࣙࣥ㸳㸸ࣇ࢕ࣜࣆࣥࡢⅆᒣ(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
ࠕࣇ࢕ࣜࣆࣥࡢࣆࢼࢶ࣎ⅆᒣᒣ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㸧࣭ᒣᓮᆂ஧࣭୰す฼඾࣭ዟ㔝 ඘㸦⚟ᒸ኱㸧
ࠕࣃ࢖ࢱࣥ†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
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 1-01 ᅵተヨᩱࡢᨺᑕᛶⅣ⣲ᖺ௦㸸஬ᓥ⚟Ụᓥ㸪㨣ᓅ㝆ୗࢫࢥࣜ࢔ࡢ౛
ዟ㔝 ඘㸦⚟ᒸ኱࣭⌮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 ࡢ༢ᡂⅆᒣ࠿ࡽ࡞ࡿ㸦㛗ᒸ࣭ྂᒣ㸪2004㸧
㸬㨣ᓅⅆᒣࡣ㸪㨣ᓅ㝆
ୗࢫࢥࣜ࢔ሁ✚≀┤ୗࡢᅵተ࠿ࡽ 18,090±100 BP㸦GX-25301-AMS㸧ࡢ 14C ᖺ௦ࡀᚓࡽࢀ࡚࠸
ࡿ㸦㛗ᒸ࣭ྂᒣ㸪2004㸧
㸬ࡲࡓ㸪ᗈᇦࢸࣇࣛ࡜ࡢᒙ఩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㝆ୗࢫࢥࣜ࢔ሁ✚≀ࡢᖺ௦ࢆ෌᳨ウࡍࡿࡓࡵ㸪ࡑࡢ┤ୗ
ࡢᅵተヨᩱࡢ 14C ᖺ௦ࢆຍ㏿ჾ㉁㔞ศᯒ㸦AMS㸧ἲ࡟ࡼࡾ ᐃࡋࡓ㸬᥇ྲྀヨᩱࡢ⏘≧ࢆ Fig. 2
ࡦࡢࡔࡅ
ࡋ࠾ࡘ
࡟♧ࡍ㸬ࡇࡇ࡛ࡣ㸪㨣ᓅ㝆ୗࢫࢥࣜ࢔ሁ✚≀ࡀᅵተᒙࢆ௓ࡋ࡚㸪ⅆࣀᓅⅆᒣࡢሷὠ⁐ᒾࢆそ
࠺㸬ᅵተᒙࡢᒙཌࡣ⣙ 20 cm ࡛㸪㨣ᓅ㝆ୗࢫࢥࣜ࢔ሁ✚≀┤ୗ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ᒙ఩࠿ࡽࡣ
࡝ࡕࡽ࡜ࡶ࠸࠼࡞࠸㸬ୗ఩ࡢሷὠ⁐ᒾࡢ K-Ar ᖺ௦ࡶ㸪0.05±0.03 Ma ࡛㸦㛗ᒸ࣭ྂᒣ㸪2004㸧
㸪
ᗈᇦࢸࣇࣛ࡜ࡢ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
࠸ࡿࡇ࡜ࢆ♧၀ࡋ㸪ᖺ௦್ࡀⱝ㏉ࡗ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿ㸦Okuno et al., 1997㸹ዟ㔝㸪2001㸧
㸬
-1-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡋ࠿ࡋ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ἾⅣࡸⅣ໬ᮌ∦ࢆぢ࠸ࡔࡍ࠿㸪ࡉࡽ࡟ᅵተヨᩱࢆ ᐃࡍࡿࡇ࡜ࡶ
⪃࠼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-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 1-02 ஑ᕞࡢⅆᒣࣇࣟࣥࢺ࡟࠾ࡅࡿ࣐ࢢ࣐⏕ᡂࣉࣟࢭࢫ
㹼࣓ࣝࢺໟ᭷≀࠿ࡽࡢ࢔ࣉ࣮ࣟࢳ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⪺ᓅ࡟ࡘ࠸࡚㸪ࡑࢀࡽࡢⅆᒣᄇฟ≀୰࡟ྵࡲࢀࡿ࢝ࣥࣛࣥ▼ᩬᬗ୰ࡢ
࣓ࣝࢺໟ᭷≀ࡢ໬Ꮫ⤌ᡂ࠿ࡽ㸪ึ⏕࣐ࢢ࣐ཬࡧࢫࣛࣈὶయࡢ⤌ᡂࡢ᥎ᐃࢆヨࡳࡓ㸬࢝ࣥࣛࣥ
▼ࡣ࣐ࢢ࣐ࡢ⤖ᬗศ໬ࡢ᪩ᮇ࡟ᬗฟࡍࡿ㖔≀࡛࠶ࡾ㸪ࡑࡢ୰࡟ᤕ⋓ࡉࢀࡓ࣓ࣝࢺໟ᭷≀ࡣࡼ
ࡾᮍศ໬࡞᫬ࡢ࣐ࢢ࣐ࡢ⤌ᡂࢆಖᣢࡍࡿࡇ࡜ࡀᮇᚅ࡛ࡁࡿ㸬᥎ᐃࡋࡓึ⏕࣐ࢢ࣐ཬࡧࢫࣛࣈ
ὶయࡢ⤌ᡂ࠿ࡽ㸪஑ᕞࡢⅆᒣࣇࣟࣥࢺ࡟࠾ࡅࡿ࣐ࢢ࣐⏕ᡂࣉࣟࢭࢫ࡟ࡘ࠸᳨࡚ウࡋࡓ㸬
᥎ᐃࡋࡓึ⏕࣐ࢢ࣐ࡢ⤌ᡂཬࡧࢫࣛࣈὶయࡢ⤌ᡂ࠿ࡽ㸪㧗࠸ K2O 㔞ࡢ㜿⸽࣭஑㔜㸪ప࠸ K2O
㔞ࡢ㟝ᓥ࣭㛤⪺ࡢ 2 ࡘࡢࢢ࣮ࣝࣉ࡟ศࡅࡿࡇ࡜ࡀ࡛ࡁࡓ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࠶ࡿࡢ࡟ᑐࡋ㸪㟝ᓥ࣭
㛤⪺ࡢ┤ୗ࡛ࡣ⣙ 100 km ࡛࠶ࡿ㸬ᆅୗ 110 km ௨῝࡟࠾࠸࡚㸪ỿࡳ㎸ࡴᾏὒࣉ࣮ࣞࢺ࠿ࡽࣇ
࢙ࣥࢪࣕ࢖ࢺࡀ⬺Ỉศゎࡋ K2O ࡀᨺฟࡉࢀࡿࡇ࡜ࡀᣦ᦬ࡉࢀ࡚࠸ࡿ㸦Schmidt, 1996㸧
㸬ࡲࡓ㸪
㜿⸽࣭஑㔜࡜㟝ᓥ࣭㛤⪺ࡢ඲ᒾࡢ Ba 㔞㸦Ba ࡣࣇ࢙ࣥࢪࣕ࢖ࢺࡢࢺ࣮ࣞࢧ࣮㸹Zack et al., 2001㸧
-4-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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
௨ୖࡢࡇ࡜࠿ࡽ㸪㜿⸽࣭஑㔜ᆅᇦ࡛ࡣ㸪ỿࡳ㎸ࡴࣉ࣮ࣞࢺࡀ 140 km ࡢ῝ᗘ࡟㐩ࡋ㸪ࣉ࣮ࣞ
ࢺෆࡢࣇ࢙ࣥࢪࣕ࢖ࢺࡀ⬺Ỉศゎࡍࡿࡇ࡜࡟ࡼࡗ࡚ K ࡀᨺฟࡉࢀ㸪ࡇࢀࡀึ⏕࣐ࢢ࣐࡟௜ຍ
ࡍࡿࡇ࡜࡛⤖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ཬࡧࣉ࣮ࣞࢺ࠿ࡽ⬺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ᆺ໬࡟ྥࡅ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
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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࡞ᙧែࡢⅆᒣ࠿ࡽᵓᡂࡉࢀࡿⅆᒣ⩌࡛࠶ࡾ㸪ⅆᒣయࡢศ㢮ࢆ⾜࠺ࡢ࡟
Ⰻዲ࡞ࣇ࢕࣮ࣝࢻ࡜࡞ࡿ㸬ᒣ㡬ࢆ୰ᚰ࡟〈㔝ࡀᗈࡀࡿᡂᒙⅆᒣ࡜ఝࡓᙧែࡢ㧗༓✑ᓠ㸪ᚚ㖊
ࡣ㸪஭ࣀୖ㸦1988㸧
㸪⟄஭࣭௚㸦2007㸧࡟ࡼࡗ࡚ᛴ⃭࡟ᡂ㛗ࡋࡓⓎ㐩㐣⛬ࡀ᫂ࡽ࠿࡟ࡉࢀ࡚
࠸ࡿ㸬ࡇࡢᵝ࡞᥎⛣࡟ࡘ࠸࡚㸪㟝ᓥⅆᒣ⩌ࡢ௚ࡢఝࡓⅆᒣ࡟࠾࠸࡚ࡶ㉳ࡁ࡚࠸ࡿࡢ࠿᳨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ಀࢆ᫂ࡽ࠿࡟ࡍࡿࡇ࡜ࡀ࡛ࡁࡓࡓࡵ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࡟㸪㝆ୗࢫࢥࣜ࢔ᒙࡀ࠶ࡿࡇ࡜ࡀ▱ࡽࢀ࡚࠸ࡿ㸬ࡇࡢ㝆ୗࢫࢥࣜ࢔ᒙࡣ㸪㣤┒ᒣ࡟
ྥ࠿࠸ᒙཌࢆቑࡍࡇ࡜ࡼࡾ㸪㣤┒ᒣࢫࢥࣜ࢔ᒙ࡜࿧ࡤࢀ࡚࠸ࡓ㸦㐲⸨࣭ᑠᯘ࣮࣒ࣟ◊✲ࢢࣝ
࣮ࣉ, 1969㸧
㸬୍᪉㸪Imura㸦1992㸧ࡣ㸪ྠᒙࡢ➼ᒙཌ⥺ᅗࡼࡾ㡑ᅜᓅࡀ⤥※࡛࠶ࡿ࡜᥎ᐃ
ࡋ㸪㡑ᅜᓅࢫࢥࣜ࢔࡜ᨵ⛠ࡋࡓ㸬⏣ᓥ࣭ᑠᯘ㸦2011㸧ࡣ㸪ྠᒙࡢ➼ᒙཌ⥺㸪⢏ᚄࡀ⏋ᓅ㸦௨
ୗ㸪⏋ᓅⅆᒣ㸧࡟ྥ࠿࠸ቑຍࡍࡿࡇ࡜ࢆ♧ࡋ㸪⏋ᓅࢸࣇࣛ࡜෌ᐃ⩏ࡋࡓ㸬ḟ࡟㸪⏋ᓅⅆᒣࢆ
㉳※࡜ࡍࡿ⁐ᒾࡣ㸪㟝ᓥⅆᒣ⩌ࡢ໭ᇦ࡟ᗈࡃศᕸࡋ࡚࠾ࡾ㸦ᅗ 1: ἑᮧ࣭ᯇ஭, 1957; ஭ᮧ࣭
ᑠᯘ, 2001㸧
㸪ⅆཱྀ࠿ࡽࡢ฿㐩㊥㞳ࡣ 7 km ࢆ㉸࠼ࡿ㸬⏋ᓅ⁐ᒾࡢ⾲㠃✚ࡣ⣙ 30 km2 ࡜࡞ࡾ㸪
Ᏻᒣᒾ⁐ᒾ࡜ࡋ࡚ࡣつᶍࡢ኱ࡁ࡞ࡶࡢ࡛࠶ࡿ㸬2011 ᖺ 11 ᭶࠿ࡽጞࡲࡗࡓすஅᓥ࡟࠾࠸࡚኱
㔞ࡢ⁐ᒾᄇฟࡀ⥅⥆ࡋ࡚࠸ࡿ⌧ᅾ㸪኱つᶍ࡞⁐ᒾᄇฟ౛࡜ࡋ࡚ࡶࡑࡢᄇⅆ᥎⛣ࢆ♧ࡍᚲせࡀ
࠶ࡿ㸬
⏋ᓅⅆᒣࡢάືࡣ㸪ึᮇ࡟ᑠ㹼୰つᶍࡢࣈࣝ࢝ࣀᘧᄇⅆࡢάື࠿ࡽጞࡲࡗࡓ㸬Ks-1㹼Ks-5
ࡣᑠ㹼୰つᶍࡢᄇⅆάືࢆ⾜ࡗ࡚࠸ࡓࡀ㸪Ks-6 ࡢ᫬࡟ᛴ࡟኱㔞ࡢ⁐ᒾ࡜㝆ୗⅆ○≀ࢆᄇฟࡍ
ࡿᄇⅆάື࡟ኚ໬ࡋࡓ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࡞࠿ࡗࡓ࡜᥎ᐃࡉࢀࡿ㸬ᇛࣨᓮ࡛ࡣ Ks-7a
㹼Ks-8 㛫࡟ἾⅣᒙ㸪†ᡂᒙࡀㄆࡵࡽࢀࡿࡇ࡜ࡼࡾ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 ᖺ๓࠿ࡽάືࢆ㛤ጞࡋ㸪500 ᖺᚋ࡟ᒣయࢆᡂ㛗ࡉࡏࡓ㧗ཎࢫ
ࢥࣜ࢔ᄇⅆࢆⓎ⏕ࡉࡏࡓ㸦⟄஭࣭௚㸪2007㸧
㸬㧗༓✑ᓠ」ྜⅆᒣࡶ㸪ྂ㧗༓✑㸫ⵦ∹⏣ࢸࣇ
ࣛࡢᄇฟ࠿ࡽ 1000 ᖺෆ࡟୺ࡓࡿάືࡀ⏕ࡌ㸪㧗༓✑ᓠ㸫⋤Ꮚࢸࣇ࡛ࣛ࡯ࡰࡑࡢάືࢆ⤊࠼
ࡓ࡜⪃࠼ࡽࢀ࡚࠸ࡿ㸦஭ࣀୖ, 1988㸧㸬᭱ึᮇࡢᑠ㹼୰つᶍࡢάື࠿ࡽ㸪๓ᮇࡢᛴ⃭࡟ᒣయࢆ
-6-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ᡂ㛗ࡉࡏࡿάື࡟⮳ࡗࡓ㸬ึᮇࡢ┦ᑐⓗ࡞ᑠつᶍ࡞άືࢆ⤒࡚㸪ᛴ⃭࡟ᡂ㛗ࡍࡿⅆᒣయࡢⓎ
㐩㐣⛬ࡣ㸪ࡇࢀࡽࡢⅆᒣ࡟ඹ㏻ࡋࡓ≉ᚩ࡜ゝ࠼㸪ᡂᒙⅆᒣࡢᡂ㛗࡟ࡣᛴ⃭࡟ᄇฟ⋡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)
ࡢ඲ᒾ໬ᏛศᯒᆅⅬ㸬侀ࡢ Ks- ࡣ⏋ᓅ⁐ᒾ┤ୖ఩ࡢ⏋ᓅࢸࣇࣛ. ⏋ᓅ⁐ᒾୖࡢ◚⥺ࡣ㸪࿘ᅖࡼ
ࡾ᪂ࡋ࠸⁐ᒾᆅᙧ.
-7-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 1-04 㟝ᓥⅆᒣ⩌㸪ᚚ㖊ⅆᒣ࡟࠾ࡅࡿ࢔ࢢࣝࢳࢿ࣮ࢺ࡜ⅆ○ὶ
⟄஭ṇ᫂㸦ࢲ࢖ࣖࢥࣥࢧࣝࢱࣥࢺ ◁㜵࣭㜵⅏஦ᴗ㒊㸧࣭
ᑠᯘဴኵ㸦㮵ඣᓥ኱Ꮫ኱Ꮫ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㏆ഐ࡟࢔ࢢࣝࢳࢿ࣮ࢺࡀᙧᡂࡉࢀࡿ࡜࡜ࡶ࡟㸪ᒣ⭡ࡸᒣ
㯄࡟ⅆ○ὶࡀὶୗࡋ࡚࠸ࡿ㸬ᮏሗ࿌࡛ࡣ㸪ࡇࢀࡽࡢ㛵ಀࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵ㸪ᒣయࢆᵓᡂࡍ
ࡿࢸࣇࣛࡸᒣ㯄ࡢⅆ○ὶࡢ⢏ᗘศᯒࢆᐇ᪋ࡋ㸪ศᕸࡸ⏘≧࡜࠶ࢃࡏ࡚ࡑࡢ㛵㐃ᛶ࡟ࡘ࠸࡚⪃
ᐹࡋࡓ⤖ᯝࢆሗ࿌ࡍࡿ㸬
2㸬࢔ࢢࣝࢳࢿ࣮ࢺ࡜ⅆ○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㏆ഐ࡟࢔ࢢࣝࢳࢿ࣮ࢺࡀᙧᡂࡉࢀࡓ㸦෗┿ 1-6㸧
㸬㟢ฟࡢⰋ࠸༡ഃᒣయᩳ
㠃࡛ࡣ࢔ࢢࣝࢳࢿ࣮ࢺࡀỈᖹ᪉ྥ࡟࠶ࡿ⛬ᗘ㐃⥆ⓗ࡟ほᐹྍ⬟࡛㸪࢔ࢢࣝࢳࢿ࣮ࢺࡢᙅ⁐⤖
㒊࡛ᑠつᶍ࡞࣮ࣟࣈࡀ⣼✚ࡋࡓᵓ㐀ࡀㄆࡵࡽࢀࡿ㸬ࡲࡓ㸪࢔ࢢࣝࢳࢿ࣮ࢺࡀพᆅᙧ࡟ཌࡃሁ
✚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࡟ศ࠿ࢀ࡚ሁ✚ࡋࡓ㸦෗┿ 7㸧
㸬
༡ഃᒣ⭡ࡢⅆ○ὶࡣᒣయᩳ㠃ࡢ≉ᐃࡢ࣮࢞ࣜࢆ㑅ᢥⓗ࡟ὶୗࡋࡓࡢ࡟ᑐࡋ㸪す㹼໭ഃᒣ㯄ࡢ
ⅆ○ὶࡣ㞄᥋ࡍࡿ௚ⅆᒣ࡜ࡢ㛫ࡢἑࢆᇙࡵ࡚ẚ㍑ⓗᗈ࠸⠊ᅖ࡟ᗈࡀࡗࡓ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-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ⅆ○ὶ࡜༊ู࡛ࡁ࡞࠸୰㛫ⓗ࡞⏘≧ࡢሁ✚≀㸧ཬࡧⅆ○ὶ࡟ࡘ࠸࡚㸪୺せ࡞㟢㢌࡛ヨᩱࢆ᥇
ྲྀࡋ㸪ࡩࡿ࠸ศࡅヨ㦂ࢆᐇ᪋ࡋࡓ㸬⢏ᚄࡣ-3 ࠿ࡽ㸺5ij ࡲ࡛ 1ij 㛫㝸࡛ 9 ༊ศࡋࡓ㸬
㝆ୗࢸࣇࣛ࡜ᒣయ㒊ࡣ㸪ࡍ࡭࡚ Walker㸦1971㸧ࡢ♧ࡋࡓࠕFallࠖࡢ㡿ᇦ࡟ࣉࣟࢵࢺࡉࢀࡿ㸬
ᒣయ㒊ࡣ㸪㝆ୗࢸࣇࣛࡀࣉࣟࢵࢺࡉࢀࡿ㡿ᇦ࡜୍㒊㔜࡞ࡿࡀ㸪඲యⓗ࡟ศ⣭ࡀᝏࡃ⢏ᚄࡀ⢒
࠸㸬ࡲࡓ㸪ᒣయ㒊ࡢ㔝እࡢ⏘≧ࡣⅆཱྀ㏆ഐ࠿ࡽᒣ㯄࡟ྥ࠿ࡗ࡚ศ⣭ࡀⰋࡃ⣽⢏࡟࡞ࡾ㸪ከᑡ
㌿ືࡋࡓࡶࡢࢆྵࡴࡀ㸪ᒣయ㒊ࡣᇶᮏⓗ࡟㝆ୗࢸࣇࣛ࡜ุ᩿ࡋ࡚Ⰻ࠸ࡔࢁ࠺㸬
ⅆ○ὶࡣ㸪ศᕸᇦ࡟ࡼࡾ␗࡞ࡿ≉ᛶࢆᣢࡘ㸬༡ഃᒣ⭡ࡢࡶࡢࡣᴫࡡ Walker㸦1971㸧ࡢࠕFlowࠖ
ࡢ㡿ᇦ࡟ࣉࣟࢵࢺࡉࢀ㸪ⅆཱྀ࠿ࡽࡢ㊥㞳࡟ᛂࡌࡓ⣔⤫ⓗ࡞ኚ໬ࡣ☜ㄆ࡛ࡁ࡞࠸㸬ࡇࡢⅆ○ὶ
ࡣ㸪ศ⣭ࡀാࡃ๓࡟ᄇ↮ᰕࡢẚ㍑ⓗప࠸㒊ศࡀᔂቯࡋࡓ㸦ࡶࡋࡃࡣⅆཱྀ࠿ࡽ┤᥋⁄ࢀฟࡋࡓ㸧
ࡇ࡜࡛ᙧᡂࡉࢀ㸪ẚ㍑ⓗప㏿ࡔࡗࡓྍ⬟ᛶࡀ࠶ࡿ㸬ࡇࡢࢱ࢖ࣉࡢⅆ○ὶ࡛ⅆཱྀ㏆ഐ࡟࢔ࢢࣝ
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พᆅᙧ࡟ẚ㍑ⓗ
ཌࡃሁ✚ࡍࡿࡇ࡜࡛ⅆཱྀ࠿ࡽ㞳ࢀࡓሙᡤ࡛ࡶ࢔ࢢࣝࢳࢿ࣮ࢺࢆᙧᡂࡋ㸪ࡉࡽ࡟ᒣ⭡ࡸᒣ㯄ࡲ
࡛ὶୗࡋࡓࡶࡢࡀ㸪ᙅ㹼㠀⁐⤖ࡢⅆ○ὶ࡜ࡋ࡚࣮࢞ࣜࡸἑࢆᇙࡵࡓ࡜⪃࠼ࡽࢀࡿ㸬
す㹼໭ഃᒣ㯄ࡢࡶࡢࡣ㸪㝆ୗࢸࣇࣛࡸᒣయ㒊࡜ẚ㍑ࡍࡿ࡜㸪ࡸࡸศ⣭ࡀᝏࡃ⢏ᚄࡀ⢒࠸ࡀ㸪
༡ഃᒣ⭡ࡢⅆ○ὶ࡜ẚ㍑ࡍࡿ࡜᫂ࡽ࠿࡟ศ⣭ࡀⰋࡃ㸪
ࠕFlowࠖ࡜ࠕFallࠖࡢ୰㛫㡿ᇦ࠿ࡽࠕFallࠖ
ࡢ㡿ᇦ࡟࠿ࡅ࡚ࣉࣟࢵࢺࡉࢀࡿ㸬ࡇࡢⅆ○ὶࡣ㸪ศ⣭ࡢ㐍ࢇࡔ㒊ศࡀᄇ↮ᰕ࠿ࡽศ㞳ࡋ࡚⏕
ࡌࡓྍ⬟ᛶࡀ࠶ࡿ㸬໭す࡟ᑐ㠃ࡍࡿ୰ᓅࡢᒣయᩳ㠃ࢆ㏺࠸ୖࡀࢀࡓࡢࡣ㸪ᄇ↮ᰕ࠿ࡽࡢᔂቯ
㧗ᗘࡀ㧗ࡃ㸪ẚ㍑ⓗ㧗㏿࡛ὶୗࡋࡓࡇ࡜ࢆ♧၀ࡍࡿ㸬୰ᓅᒣయᩳ㠃ୖ࡟㏺࠸ୖࡀࡗࡓⅆ○ὶ
ᮏయࡀṧᏑ࡛ࡁ࡞࠿ࡗࡓࡼ࠺࡟㸪ᚚ㖊ⅆᒣࡢᒣయᩳ㠃࡛ࡶⅆ○ὶࡀṧࡽ࡞࠿ࡗࡓࡢ࡛࠶ࢁ࠺㸬
ࡇࡢࢱ࢖ࣉࡢⅆ○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ⅆཱྀ࠿ࡽ┤᥋⁄ࢀฟࡍࡼ࠺࡞ⅆ○ὶࡀⅆཱྀ㏆ഐ࡛⣼✚ࡋ࢔ࢢࣝࢳࢿ࣮
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ከࡃࡢⅆᒣ࡛࢔ࢢࣝࢳࢿ࣮ࢺࡀほᐹ࡛ࡁ㸪ᑡ࡞ࡃ࡜ࡶ㧗༓✑
ᓠࡸ᪂⇞ᓅ࡛ࡶ 106 㹼107 m3 ࣮࢜ࢲ࣮ࡢ‽ࣉࣜࢽ࣮ᘧᄇⅆ࡟క࠺ⅆ○ὶ࡟ࡼࡗ࡚㸪ⅆཱྀ㏆ഐ࡟
࢔ࢢࣝࢳࢿ࣮ࢺࡀᙧᡂࡉࢀ࡚࠸ࡿ㸬ᚚ㖊ⅆᒣ࡛ࡶᑠつᶍࡔࡀ㝆ୗࢸࣇࣛ㉳※ࡢ࢔ࢢࣝࢳࢿ࣮
ࢺࡀᏑᅾࡋ㸪ᮏሗ࿌ࡣ㝆ୗࢸࣇࣛ㉳※ࡢ࢔ࢢࣝࢳࢿ࣮ࢺࡢᏑᅾࢆྰᐃࡍࡿࡶࡢ࡛ࡣ࡞࠸ࡀ㸪
Ᏻᒣᒾ㉁ⅆᒣࡢⅆཱྀ㏆ഐ࡟ࡣⅆ○ὶ㉳※ࡢ࢔ࢢࣝࢳࢿ࣮ࢺࡀ࠿࡞ࡾᏑᅾࡍࡿ࡜ᛮࢃࢀࡿ㸬
ⅆཱྀ㏆ഐࡢ࢔ࢢࣝࢳࢿ࣮ࢺࢆ㸪㟢㢌༢఩࡛㝆ୗࢸࣇࣛ㉳※࠿ⅆ○ὶ㉳※࠿ุ᩿ࡍࡿࡇ࡜ࡣ
-9-
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ᅔ㞴࡞ࡇ࡜ࡀከ࠸ࡀ㸪ᄇⅆᵝᘧࡀ‽ࣉࣜࢽ࣮ᘧᄇⅆ㸦ᑡ࡞ࡃ࡜ࡶ 106 㹼107 m3 ⛬ᗘ㸧࡛࠶ࡿࡇ
࡜㸪ᒣ⭡ࡸᒣ㯄࡟ⅆ○ὶࡀศᕸࡍࡿࡇ࡜ࡀ㸪᭷ຠ࡞ุ᩿ᮦᩱ࡟࡞ࡿ࡜⪃࠼ࡿ㸬
෗┿ 1 ⅆཱྀ⦕࡛ࡳࡽࢀࡿ࢔ࢢࣝࢳࢿ࣮ࢺ㸦ThT-c㸧
෗┿ 2 ෗┿ 1 ࡢ࢔ࢢࣝࢳࢿ࣮ࢺ࡜ྠᒙ‽ࡢᮎ➃㒊࡛ࡳࡽࢀࡿᑠつᶍ࡞࣮ࣟࣈ㸦ThT-c㸧
- 10 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ෗┿ 3 ⅆཱྀ㏆ഐ࡛ࡳࡽࢀࡿ࢔ࢢࣝࢳࢿ࣮ࢺ㸦ThT-c㸧
෗┿ 4 ෗┿ 3 ࡢ࢔ࢢࣝࢳࢿ࣮ࢺ࡜ྠᒙ‽ࡢᮎ➃㒊࡛ࡳࡽࢀࡿཌ࠸࢔ࢢࣝࢳࢿ࣮ࢺ㸦ThT-c㸧
- 11 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 1-05 㨣⏺࢝ࣝࢹࣛ㸪ᖾᒇⅆ○ὶ࡟ࡼࡿᆅᒙᶓ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⯡࡟࢔࢝࣍ࣖᄇⅆ࡜ࡼࡤࢀ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ᮾ໭ᆅ᪉ࡲ࡛ศᕸࡍࡿ㸦⏫⏣࣭᪂஭㸪1978㸧
㸬ᄇⅆࡢ㏵୰࡛
ࡣᄇ♟⌧㇟ࢆక࠺ࡼ࠺࡞ 2 ᅇࡢ኱ᆅ㟈ࡀⓎ⏕ࡋࡓ㸦ᡂᑿ࣭ᑠᯘ㸪2002㸧㸬
㸰 ᖾᒇⅆ○ὶ࡟ࡼࡿᆅᒙᶓ㌿
Ky ࡀሁ✚ࡋࡓ⠊ᅖ࡛ࡣ㸪ࡑࢀࡼࡾୗ఩ࡢ Ky-p ᒙ࠾ࡼࡧྂᅵተᒙࡀ㸪ᒁ㒊ⓗ࡟ᩘ 10r㹼ᆶ
┤࡟ᶓ㌿ࡍࡿᆅᒙᶓ㌿⌧㇟ࡀㄆࡵࡽࢀࡿ㸬ᆅᒙᶓ㌿ࡢ᪉ྥࡣ࠾࠾ࡴࡡ༡࠿ࡽ໭࡛࠶ࡿ㸬
A distribution map of Overturned strata caused by Koya ignimblite
- 14 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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༡஑ᕞᕷ㏕℩ᡞ࡟ᡤᅾࡍࡿ๓ཎ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⢓㉁ࣟ
࣮࣒ᒙ࠿ࡽጞࡲࡾ㸪㯮Ⰽ⭉᳜ᅵᒙࡲ࡛ཬࢇ࡛࠸ࡿ㸬ࡑࢀࡒࢀࡢᆅᒙᶓ㌿᪉ྥࡣ໭㹼す࡬࡜ኚ
໬࡟ᐩࡴࡀ㸪࠾࠾ࡼࡑࡢഴྥ࡜ࡋ࡚ࡣ໭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఩
࡟㸪ྂ࠸᪉࠿ࡽΎ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ࡀⴭࡋࡃ஘ࡉࢀ࡚࠸ࡿ㸬ᶓ㌿
ࡋࡓࣈࣟࢵࢡࡣ Ky ࠾ࡼࡧ K-Ah ࡟ࡼࡾそࢃࢀ࡚࠸ࡿ㸬
㑇㊧༡す㒊࡛ࡣ⣙ 50㹫㸰࡟㸯ಶ⛬ᗘࡢ๭ྜ࡛ᆅᒙᶓ㌿ࡀᏑᅾࡋࡓࡀ㸪ࡑࡢᖹ㠃ᙧែࡣ෇ᙧ
࡞࠸ࡋࡣᴃ෇ᙧ࡛㸪᭱኱㛗㸳㹫࠿ࡽ㸯㹫⛬ᗘࡲ࡛つᶍࡣᵝࠎ࡛࠶ࡗࡓ㸬㑇㊧ෆ࡟࠾ࡅࡿᆅᒙ
ᶓ㌿ࡢศᕸࡣ୙つ๎࡛㸪㞟୰ࡸᐃྥᛶࡣㄆࡵࡽࢀ࡞࠸ࡇ࡜࠿ࡽ㸪ே㢮άື࡟ࡼࡿ㑇ᵓ࡛ࡣ࡞
࠸࡜ุ᩿ࡉࢀࡿ㸬ᶓ㌿ࡢ᪉ྥࡣ࠾࠾ࡴࡡ໭໭ᮾ᪉ྥ࡛࠶ࡿࡀ㸪⸃ᦶ༙ᓥࡢᇽᒣ㏕㑇㊧ྠᵝ㸪
ಶࠎࡢᆅᒙᶓ㌿ࡣᚲࡎࡋࡶྠ୍᪉ྥࢆ♧ࡍ࡜ࡣ㝈ࡽ࡞࠸ࠋ࿘㎶ࡢᆅᙧࡢᙳ㡪ࡸⅆ○ὶෆ㒊ࡢ
஘ὶ≧ἣࢆ཯ᫎࡋ࡚࠸ࡿ࡜ᛮࢃࢀࡿࡀ㸪࠾࠾ࡼࡑࡢഴྥ࡜ࡋ࡚㨣⏺࢝ࣝࢹࣛ࡜཯ᑐ᪉ྥ࡟ᶓ
㌿ࡋ࡚࠸ࡿ㸬
㸱 ᖾᒇⅆ○ὶ࡟ࡼࡿᆅᒙᶓ㌿ࡢ㐣⛬
㑇㊧࡛ࡢほᐹ࡟ࡼࡿ࡜㸪㨣⏺࢔࢝࣍ࣖᄇⅆࡢึᮇᄇฟ≀࡛࠶ࡿ Ky-p ࡶᶓ㌿ࡋ࡚࠸ࡿࡇ࡜㸪
Ky ࡟☜ᐇ࡟そࢃࢀࡿࡇ࡜࠿ࡽᆅᒙᶓ㌿ࡢࢱ࢖࣑ࣥࢢࡣ Ky-p ࡢ㝆ୗ┤ᚋ࡜ุ᩿ࡉࢀࡿ㸬ከࡃ
ࡢ౛࡛ᶓ㌿ࡋࡓྂᅵተᒙࣈࣟࢵࢡࡢ㝽㛫ࢆ Ky ࡀᇙࡵࡿࡼ࠺࡟ධࡾ㎸ࢇ࡛࠸ࡿࡇ࡜࠿ࡽ㸪Ky
࡟ࡼࡾᶓ㌿ࡀ⏕ࡌࡓᚋ㸪ᘬࡁ⥆ࡁὶ㉮ࡋ࡚ࡁࡓ Ky ࡀ㝽㛫ࢆᇙࡵሁ✚ࡋࡓ࡜ุ᩿ࡉࢀࡿ㸬
ࡇࡢࡼ࠺࡞ Ky-p㸪Ky ࡜ࡢ⿕そ㛵ಀ㸪ᆅᒙᶓ㌿ࡀ⣙ 50㹫㸰ࡈ࡜࡟Ꮡᅾࡍࡿࡇ࡜㸪ᶓ㌿ࡋࡓ
ࣈࣟࢵࢡࡢ୰ᚰ࡟ᶞᮌࡢ⑞㊧࡜⪃࠼ࡽࢀࡿ⭉᳜ᅵተࡀᏑᅾࡍࡿ౛࡞࡝࠿ࡽ㸪ᙜ᫬ࡢᆅ⾲㠃࡟
⏕࠼࡚࠸ࡓᶞᮌࡀ㸪Ky ࡟ࡼࡿ┤ᧁࢆཷࡅ᰿㖊ࡈ࡜࡞ࡂಽࡉࢀ㸪ᆅᒙᶓ㌿ࡀᙧᡂࡉࢀࡓ࡜ุ
᩿ࡉࢀࡿ㸬
- 15 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 1-06 ⇕࣑ࣝࢿࢵࢭࣥࢫ㸦TL㸧ᖺ௦࠾ࡼࡧ඲ᒾ໬Ꮫ⤌ᡂ࡟ࡼࡿ
ᯇࡢྎᒾᒌ࡞ࡔࢀሁ✚≀ࡢ⤥※᥎ᐃ
ᆏཱྀ ᕦ࣭ᰆཎ㞞ᶞ࣭ᒣᓮᆂ஧࣭ዟ㔝 ඘㸦⚟ᒸ኱࣭⌮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 ᖺ௦࡜඲ᒾ໬Ꮫ⤌ᡂ࠿ࡽ MDA ࡢ⤥※࡜ὶୗ㐣⛬ࢆ⪃ᐹࡋࡓࡢ
࡛ሗ࿌ࡍࡿ㸬
‫‮‬ἑᒣࡣᆅᙧⓗ࡟ 2 ᯛࡢࣇ࣮ࣟࣘࢽࢵࢺࡀㄆࡵࡽࢀࡿࡀ㸪ᒾ▼ⓗ࡟ఝ࡚࠸ࡿࡇ࡜࠿ࡽ୍ᣓ
ࡋ࡚‫‮‬ἑ⁐ᒾ࡜ࡉࢀ࡚ࡁࡓ㸦ᑠ㔝㸪1963㸹ኴ⏣㸪1991㸧
㸬ࡋ࠿ࡋ㸪ୗ㒊⁐ᒾྎᆅࡢ㛤ᯒᗘ࡜ࡑ
ࡢୖ࡟ MDA ࡟ᑐẚࡉࢀࡿᔂቯሁ✚≀ࡀ஌ࡿ⏘≧࠿ࡽ㸪
ୗ‫‮‬ἑ⁐ᒾ࡜ୖ‫‮‬ἑ⁐ᒾ࡟༊ูࡍࡿ㸬
୕ಛᒣすᓠࡣୗ‫‮‬ἑᒣ⁐ᒾࡀᙧᡂࡍࡿ⁐ᒾྎᆅୖ࡟఩⨨ࡋ㸪໭࡟㛤ࡃ㤿㋟ᙧ࢝ࣝࢹࣛࡢ୍㒊
ࡀ☜ㄆ࡛ࡁࡿ㸬⌧ᅾࡢ୕ಛᒣࡢ໭ഃⅆཱྀ࡟ࡣୖ‫‮‬ἑ⁐ᒾࡢ⁐ᒾὶ⑞ࡀㄆࡵࡽࢀࡿ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ᗎ࡜ㄪ࿴ⓗ࡛࠶ࡿ㸬
MDA ࡢศᕸᇦ࡟ࡣὶࢀᒣᆅᙧࡀከᩘᏑᅾࡋ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ᒾሢ࡟ࡣࢪࢢࢯ࣮ࢡࣛࢵࢡᵓ㐀ࡀⓎ㐩ࡋ㸪ከࡃࡢ㟢㢌
- 16 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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┙ᅵተᒙ࡜ࡢቃ⏺┦࡛
ࡣ┤ᚄ 5 ੉௨ୖࡢ♟ࢆྵࡲࡎ㸪ࡼࡾ኱ࡁ࡞ᒾሢࡸᒾ∦ࡣሁ✚≀୰ࡢ୰㒊࡟㞟୰ࡍࡿ㸬
MDA ࡟ࡣ୺࡟㸪㯮㞼ẕྵ᭷ᩳ᪉㍤▼༢ᩳ㍤▼ゅ㛝▼Ᏻᒣᒾ࡛▼ᇶࡀ࢖ࣥࢱ࣮ࢧ࣮ࢱࣝ⤌⧊
ࢆ♧ࡍࡶࡢ㸦A ࢢ࣮ࣝࣉ㸧
㸪㯮㞼ẕྵ᭷༢ᩳ㍤▼ᩳ᪉㍤▼ゅ㛝▼Ᏻᒣᒾ࡛▼ᇶࡀࣁ࢖࢔ࣟࣆࣜ
ࢸ࢕ࢵࢡ⤌⧊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✚≀ࢆᒣయᔂቯ᫬࡟ྲྀࡾ㎸ࢇࡔࡶࡢࡀ MDA ୰ࡢ
ⅆ○ὶࣈࣟࢵࢡ࡛࠶ࡿྍ⬟ᛶࡀ㧗࠸㸬ࡇࢀࡽࡢ≉ᚩ࠿ࡽ㸪MDA ࡢὶືᶵᵓ࡜ࡋ࡚ࣉࣛࢵࢢࣇ
࣮ࣟࣔࢹࣝ㸦୕ᮧ࡯࠿㸪1988㸧ࡀᙜ࡚ࡣࡲࡿ㸬⤥※ࡣ୕ಛᒣすᓠ࡛࠶ࡿ࡜⪃࠼ࡽࢀ㸪 ὶୗࡲ
࡛ࡢࣉࣟࢭࢫࡣୗ‫‮‬ἑ⁐ᒾࡀ⁐ᒾྎᆅࢆᙧᡂࡋࡓᚋ㸪ࡑࡢୖ࡟୕ಛᒣすᓠࢆᙧᡂࡍࡿ⁐ᒾࢻ
࣮࣒ࡀᡂ㛗ࡋ࡚ᒣయᔂቯࢆ㉳ࡇࡋ㸪࿘㎶ࡢⅆ○ὶሁ✚≀ࢆ࡜ࡾ㎸ࢇ࡛ MDA ࢆ⌧ᅾࡢᆅᇦ࡟
ሁ✚ࡉࡏࡓ㸬MDA ᇶᗏ㒊ࡢ๧᩿ᛂຊ࡟ࡼࡾ㸪ᇶ┙࡛࠶ࡿ B ࢢ࣮ࣝࣉࡢᏳᒣᒾࡀࡦࡁࡣࡀࡉ
ࢀ㸪MDA ࡟ྲྀࡾ㎸ࡲࢀࡓ㸬ࡑࡢᚋࡍࡄ࡟୕ಛᒣ⁐ᒾࢻ࣮࣒ࡀᡂ㛗ࡋ࡚ᔂቯⅆཱྀࢆ࡯ࡰᇙ✚ࡋ㸪
᭱ᚋ࡟ୖ‫‮‬ἑ⁐ᒾࡀୗ‫‮‬ἑ⁐ᒾࡢ୍㒊ࢆそ࠺ᙧ࡛໭ഃ࡟ὶࢀࡓࡢࡔ࡜⪃࠼ࡽࢀࡿ㸬
MDA ࡢὶୗ㐣⛬ࡣ㸪ୗ‫‮‬ἑ⁐ᒾࢆそࡗ࡚ὶୗࡋࡓὶࢀ࡜୕ಛᒣすᓠ࠿ࡽ໭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
ὶୗࡋࡓࡇ࡜ࡀ♧၀ࡉࢀࡿ㸬
- 17 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 Fig. 1
Thermoluminesence age of the Matsunodai Debris Avalanches Deposit.
- 18 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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ࡋ࠿ࡋ㸪ࡑࡢከࡃࡣࢩࢫࢸ࣒࡜ࡋ࡚࠺ࡲࡃᶵ⬟ࡋ࡚࠸࡚ࡶ㸪ࢹ࣮ࢱ
ࡢ୰㌟ࡸ㉁࡟㛵ࡋ࡚ࡣㄢ㢟ᒣ✚࡜࠸࠺ࡢࡀᐇែ࡛࠶ࢁ࠺㸬➹⪅ࡀࡇࡢᩘᖺ㛫࠿࠿ࢃࡗ࡚ࡁࡓ
ࡶࡢ࡟⮬↛⅏ᐖࡢࢹ࣮ࢱ࣮࣋ࢫ໬ࡀ࠶ࡿࡀ㸪ࡇࢀ࡛ࡶᇶ♏ࢹ࣮ࢱࡢ㔜せᛶ࡜࡜ࡶ࡟ࡑࢀ࡟ࡓ
࡝ࡾ╔ࡃࡇ࡜ࡢᅔ㞴ࡉࢆ③ឤࡋࡓ㸬ὥỈ㸪ᆅ㟈㸪ὠἼ㸪ᄇⅆ࡞࡝࡟ࡼࡿ⅏ᐖグ㘓ࡣྛᆅ࡟ከ
ᩘᩓᅾࡍࡿࡀ㸪኱༙ࡣఏ⪺グ㘓࡛࠶ࡾ㸪ఏ㐩㐣⛬ࡢࣇ࢕ࣝࢱࣜࣥࢢ࡛ෆᐜࡸ㉁ࡣ኱ࡁࡃኚ໬
ࡋ࡚࠸ࡿ㸬
ᆅ㉁ᅗ࡜㛵㐃㈨ᩱࡶ⭾኱࡞ᩘࡀ⏬ീ࡞࡝ࡢ࠿ࡓࡕ࡛බ㛤ࡉࢀ㸪ᐜ᫆࡟࢔ࢡࢭࢫ࡛ࡁࡿࡼ࠺
࡟࡞ࡗࡓࡀ㸪ᐊෆ࡛ࡢศᯒ್➼ࢆ㝖ࡅࡤ㸪ࡑࢀࡽࡢከࡃࡣ㔝እࢹ࣮ࢱࡀᇶ♏࡜࡞ࡗ࡚࠸ࡿ㸬
ࡇࡢࡼ࠺࡟ࡳࢀࡤ㸪㔝እ࠿ࡽ࠸࠿࡟ࡋ࡚౯್࠶ࡿࢹ࣮ࢱࢆ▷ᮇ㛫࡟⥙⨶ⓗ࡟ྲྀᚓࡍࡿ࠿ࡀࡇ
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ࡸಶே࡟ࡼࡗู࡚ࠎ
࡟ᚓࡽࢀ࡚࠸ࡿࡇ࡜࠿ࡽ㸪ᇶ♏ࢹ࣮ࢱ࡜ࡋ࡚ࡑࢀࡽࢆ㞟✚ࡋ࡚౪ࡍࢀࡤ㸪ᆅ㉁Ꮫྛศ㔝ࡢⓎ
ᒎ࡟ࡶ㈨ࡍࡿ࡜ࡢ⪃࠼࠿ࡽ࡛࠶ࡗࡓ㸬ࡋ࠿ࡋ㸪㟢㢌࡜࠸࠼࡝ࡶ✵㛫ෆ࡛ࡣࠕⅬ࡛ࠖࡣ࡞ࡃ㸪
㸱ḟඖⓗ࡞ᗈࡀࡾࢆࡶࡗ࡚࠸ࡿࡋ㸪ᒾ▼ࢱ࢖ࣉ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ࡇࢀࡽ࡬ࡢᑐฎࡀ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௒᪥࡛ࡶ኱ࡁࡃ࠿ࢃࡿࡶࡢ࡛ࡣ࡞࠸ࡀ㸪㟢㢌ࢹ㸫ࢱ࣮࣋ࢫࡢ฼⏝┠ⓗࡸ⎔
ቃࡣࡇࡢ 20 ᖺ㛫࡟኱ࡁࡃኚ໬ࡋ࡚ࡁࡓ㸬♫఍඲య࡟⮬↛ࣁࢨ࣮ࢻ࡜⅏ᐖ࡟㛵ࡍࡿ㛵ᚰࡀ㧗
- 19 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡲࡾ㸪ᵓ㐀≀ࡸ࢖ࣥࣇࣛᩚഛ࡟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ࡀࡑࢀࢆ⿬௜ࡅ࡚࠾ࡾ㸪ࡑࢀࡽࡣࢹ࣮ࢱ࣮࣋ࢫࡢฟຊ⾲⌧࡛ࡶ
࠶ࡿ㸬ࡲࡓ㸪ࡇࢀ࡟㛵㐃ࡋ࡚㸪┠ⓗࢆ㝈ᐃࡋࡓࢺࣞࣥࢳㄪᰝࡸ࣮࣎ࣜࣥࢢㄪᰝࡀᗈࡃᐇ᪋ࡉ
ࢀࡿࡼ࠺࡟࡞ࡾ㸪ࢺࣞࣥࢳቨ㠃ࡸ࣮࣎ࣜࣥࢢࢥ࢔➼㸪㟢㢌௨እࡢ㔝እࢹ࣮ࢱࡀᛴቑࡋ࡚ࡁ
ࡓ㸬ά᩿ᒙ࡜ࡑࢀࢆそ࠺ࢸࣇࣛࡢ㔝እࢹ࣮ࢱ࡛ࡶࡇࡢ✀ࡢࡶࡢࡀ኱༙ࢆ༨ࡵࡿࡼ࠺࡟࡞ࡗ࡚
࠸ࡿ㸬
ࡇ࠺ࡋࡓ฼⏝㠃ࡢኚ໬ࢆ⪃៖ࡍࢀࡤ㸪㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢᵓ⠏ࡣ༢࡟ᆅ㉁ᅗసᡂࡢࡓࡵ
ࡢᇶ♏ࢹ࣮ࢱ࡜ࡋ࡚ࡔࡅ࡛࡞ࡃ㸪ᆅ㉁ᅗసᡂࢆ⤒࡞࠸࡛ᐇ♫఍࡛┤᥋฼⏝࡛ࡁࡿࢹ࣮ࢱࢆ
ᅗ-2㸧㸬ࡇࡢሙྜ㸪ᆅ㉁ࣔࢹࣝᵓ⠏ࡢࢫࢸࢵࣉࢆᚲࡎྵࡴ
ࡶᥦ౪࡛ࡁ࡞ࡅࢀࡤ࡞ࡽ࡞࠸㸦ᅗ
ࡇ࡜ࡣ࡞ࡃ࡞ࡿࡀ㸪᪂ࡓ࡞ㄢ㢟࡜ࡑࢀ࡬ࡢྲྀࡾ⤌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♫఍ࡢࢱ࢖࣒ࢫࢣ࣮ࣝ⢭ᗘ࡟㏆࠸࠿ࡓࡕ
ࡢࡶࡢ࡛ᚓࡽࢀࡿ࠿㸪࠶ࡿ࠸ࡣࡑࢀ࡟ኚ᥮࡛ࡁࡿࡇ࡜ࡀᮃࡲࢀࡿ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࡜ࡋ࡚ಖᏑࡉࢀࡓࠕࡶࡢࠖࡸࠕ࠿ࡓࡕࠖࢆᚓࡿࡔࡅ࡛࡞ࡃ㸪ࡑ
ࢀࡽࢆࡶ࡜࡟ᐇ♫఍ࡢࢱ࢖࣒ࢫࢣ࣮ࣝ⢭ᗘ࡟㏆࠸࠿ࡓࡕ࡛ࠕ⌧㇟ࠖࢆ᥎ᐃ࡛ࡁࢀࡤ㸪ᐇ♫
఍࡛ࡢ฼⏝࡟㈨ࡍࡿ࡜ࡇࢁࡀ኱ࡁ࠸㸬
- 20 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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࡜ྠᵝ࡟ྲྀࡾᢅ࠺ᚲせࡀ
࠶ࡿࡋ㸪࣮࣎ࣜࣥࢢࢥ࢔ࡶ୍ぢ῝ᗘ᪉ྥ࡬ࡢ୍ḟඖࢹ࣮ࢱࡢࡼ࠺࡟ぢ࠼ࡿࡀ㸪ࢥ࢔୰ࡢ⏘≧
ࡲ࡛ྵࡵࢀࡤ㸪๓⪅࡜ྠᵝࡢྲྀࡾᢅ࠸ࡀᚲせ࡜࡞ࡿ㸬ࡇࡢࡓࡵ㸪ࡇࢀࡽ࡟ࡘ࠸࡚ࡣ࠸ࡎࢀࡶ
ࠕ㟢㢌ࠖ࡜ྠᵝࡢࢹ࣮ࢱྲྀᚓ࡞࡝ࡢᑐฎࡀᚲせ࡛࠶ࡿ㸬
㏆ᖺ㸪㟢㢌ࢹ࣮ࢱ࣮࣋ࢫࡢࢩࢫࢸ࣒࡟ࠕ㛵ಀࡢ௦ᩘࠖࡸࠕࢢࣛࣇ⌮ㄽࠖࡢᑟධࡀヨࡳࡽ
ࢀ㸦Ἑす㸪2001,2003 ࡞࡝㸧
㸪ᆅ㉁ࢹ࣮ࢱࡢᩘᏛⓗ⾲⌧ࡣ㐍ᒎࡋࡓࡀ㸪ࡑࢀ࡟ぢྜࡗࡓ࠿ࡓࡕ
࡛ࡢࢹ࣮ࢱྲྀᚓࡣᐜ࡛᫆ࡣ࡞࠸㸬ᒙᗎࡸᵓ㐀㸪㈏ධ㛵ಀ࡞࡝㸪ᆅ㉁Ꮫࡢୡ⏺࡛ࡣᴫᛕࡢ」㞧
ࡉ࡟ᑐᛂࡋ࡚ࢹ࣮ࢱྲྀࡾᢅ࠸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␗࡞ࡿࡇ࡜ࡶከࠎ࠶ࡿ㸬
ࡋ࠿ࡋ㸪㸱ḟඖࢹ࣮ࢱࡢྲྀᚓ᪉ἲ࠾ࡼࡧฟຊ⾲⌧࡟㛵㐃ࡋࡓ᝟ሗᢏ⾡ࡀⴭࡋࡃ㐍ᒎࡋ㸪
෗┿㸪ࣅࢹ࢜㸪ࢫࢣ࣮ࣛࣈࣝ࡞ᆅᙧ࣭✵୰෗┿ࢹ࣮ࢱࢆేࡏࡓྲྀࡾᢅ࠸ࡶᐜ᫆࡟࡞ࡗ࡚ࡁࡓ
ࡇ࡜࠿ࡽ㸪ୖ㏙ࡋࡓ฼⏝㠃ࡢኚ໬࡬ࡢᑐᛂ࡟ຍ࠼㸪ࡇࢀࡽࡢᢏ⾡ࢆ⤌ࡳྜࢃࡏࡿࡇ࡜࡛ຠᯝ
ⓗ࡞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௒᪥࡛ࡶ᭱኱ࡢㄢ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໬
ᛴቑࡍࡿ࣮࣎ࣜࣥࢢࢥ࢔࣭
ࢺࣞࣥࢳቨ㠃࡞࡝ࡢ㔝እࢹ
࣮ࢱ࡟ࡶᑐᛂࡍࡿྲྀᚓ᪉ἲ
ࡢᶍ⣴
᪂ࡓ࡞ㄢ㢟
࣭ᐇ♫఍ࡢࢱ࢖࣒ࢫࢣ࣮ࣝ⢭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ࡑࡢሙྜ࡟ࡣ᪂ࡓ࡞ㄢ㢟ࡀ
Ⓨ⏕ࡍࡿ㸬
- 21 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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⌧᪉ἲ࡟ࡘ࠸࡚㸫㸪
᝟ሗᆅ㉁㸪14, 249-258.
బ㔝㞞அ㸪1997㸪ࢹ࢕ࢪࢱࣝࣇ࢕࣮ࣝࢻ࣐ࢵࣉ㸪᪥ᮏ᝟ሗᆅ㉁Ꮫ఍ࢩ࣏ࣥࢪ࣒࢘’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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 2-02 㟢㢌᝟ሗࡢ཰㞟࡜ඹ᭷ࡓࡵࡢ᝟ሗࢧ࢖ࢺ࡜཰㞟ᨭ᥼ࢶ࣮ࣝࡢᩚഛ
ዟᮧ ຾㸦⚟ᒸ኱࣭⥲ྜ᝟ሗฎ⌮ࢭࣥࢱ࣮㸧࣭▮⩚⏣ඃ㍤㸦⚟ᒸ኱࣭ᕤ㸧
㧗ᶫఙᘺ㸦⚟ᒸ኱࣭ᕤ㸧࣭㭯⏣┤அ㸦⚟ᒸ኱࣭ᕤ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⅏ࡸ࢔࢘ࢺ࣮ࣜࢳࡢ㠃࠿ࡽࡶ㠀ᖖ࡟㔜せ࡛࠶ࡿ㸬ᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ࡛ࡣ㟢㢌᝟ሗ
ඹ᭷ࡢⅭࡢ࢙࢘ࣈࢧ࢖ࢺࢆ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᝟ሗࡢ኱༙ࡣ
◊✲⪅ಶேࡢᡭඖ࡛཰㞟ࡋࡓከ㔞ࡢㄪᰝ⣲ᮦ࡜ࡋ࡚ᇙࡶࢀ࡚ࡋࡲ࠺ࢣ࣮ࢫࡀከ࠸㸬௬࡟཰㞟
ࡋࡓ㟢㢌᝟ሗࢆᩚ⌮ࡋ㸪ࢹ࣮ࢱ࣮࣋ࢫ໬ࡋ࡚ᗈࡃබ⾲ࡋ࡚ά⏝ࡍࡿ࡜ࡋ࡚ࡶ㸪㟢㢌᝟ሗࡣᮏ
㉁ⓗ࡟㠀ᐃᆺ࠿ࡘ⮬⏤ᗘࡢ㧗࠸ࢹ࣮ࢱ࡛࠶ࡿࡓࡵ㸪⦅⧩⪅ẖ࡟㟢㢌᝟ሗࡢ⾲グࡸ⾲⌧ࡀ␗࡞
ࡿࡇ࡜ࡶከࠎ࠶ࡿ㸬ࡲࡓ㸪ࡑࢀࡽࢆᩚ⌮㸪ᵓ⠏ࡍࡿ࡟ࡣᑓ㛛ᐙ࡟ࡼࡿᡭసᴗࢆᚲせ࡜ࡋ㸪⭾
኱࡞ேⓗ࣭᫬㛫ⓗࢥࢫࢺࢆせࡍࡿࡇ࡜࡜࡞ࡿ㸬ࡋ࠿ࡋ࡞ࡀࡽ㸪ᑡ࡞ࡃ࡜ࡶ఩⨨᝟ሗ࡟⣣࡙ࡃ
㟢㢌⏬ീ᝟ሗࡀබ㛤ࡉࢀࢀࡤ㸪௬࡟㟢㢌ࡀᾘ⁛ࡋ࡚ࡶ࣮࣎ࣜࣥࢢ᥇᥀ࡸࢺࣞࣥࢳㄪᰝࢆ⾜࠺
ࡇ࡜ࡶྍ⬟࡜࡞ࡿ࡞࡝㸪㟢㢌ࡑࡢࡶࡢࡢᏑᅾᛶࡀグ㘓㸪ඹ᭷ࡉࢀࡿࡇ࡜ࡣᴟࡵ࡚㔜せ࡛࠶ࡿ
࡜⪃࠼ࡿ㸬
ࡑࡇ࡛ᡃࠎࡣᚑ᮶࡜ࡣ␗࡞ࡿ࢔ࣉ࣮ࣟࢳ࡛ࡢ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⯡ࡢᕷẸࡢ᪉ࢆྵࡵࡓᕷẸཧຍᆺ࡟ࡼࡿᆅ㉁ࢹ࣮
ࢱࡢ཰㞟࡜᝟ሗࡢඹ᭷࡟ࡼࡿ࢔ࣉ࣮ࣟࢳࢆ┠ᣦࡋࠊ㟢㢌᝟ሗࢆ୰ᚰ࡜ࡋࡓᆅ㉁᝟ሗࡢ཰㞟࡜
ඹ᭷ࢆ┠ⓗ࡜ࡋࡓࢧ࢖ࢺࠕࡌ࠾ࣟࢢࠖ1ࢆ㛤Ⓨࡋ㸪࢖ࣥࢱ࣮ࢿࢵࢺୖ࡛බ㛤ࡋ࡚࠸ࡿ㸬ࠕࡌ࠾
ࣟࢢࠖࡣ◊✲⪅ࡸᕷẸࡢ᪉࠿ࡽ㸪㟢㢌᝟ሗࢆ୰ᚰ࡜ࡋࡓᆅ㉁ࢹ࣮ࢱ㸦୺࡟㟢㢌෗┿࡜ࡑࡢ఩
⨨㸧ࡢ᝟ሗᥦ౪ࢆཷࡅ㸪㟢㢌᝟ሗࢆඹ᭷ࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࡋࡓ᝟ሗࢧ࢖ࢺ(Fig.1)࡛࠶ࡿ㸬
1
http://www.acrifis-ehai.fukuoka-u.ac.jp/geolog/
- 23 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 㟢㢌෗┿࡞࡝ࡢ᝟ሗᥦ౪⪅ࡣ㸪ࣃࢯࢥࣥ࡞࡝࠿ࡽᮏࢧ࢖ࢺ࡬࢔ࢡࢭࢫࡋ㸪ᢞ✏࣓ࢽ࣮ࣗ
࡟ἢࡗ࡚㟢㢌෗┿ࢆᥦ౪ࡍࡿ௙⤌ࡳ࡛࠶ࡿ㸬ࡑࡢ㝿࡟㟢㢌ࡢලయⓗ࡞఩⨨ࢆ᧜ᙳ⏬ീ࡟ᇙࡵ
㎸ࡲࢀࡓ EXIF ᝟ሗࡸᥦ౪⪅ࡢᣦ♧࠿ࡽྲྀᚓࡍࡿ㸬ࡲࡓ㸪㟢㢌⏬ീࡢᥦ౪᫬࡟⡆༢࡞ࢥ࣓ࣥ
ࢺࡸ࣮࣮࢟࣡ࢻ㸦ࢱࢢ㸧ࡶ௜୚ࡋ࡚ࡶࡽ࠺㸬᭱ᑠ㝈ᗘࡢࡇࢀࡽ⿵㊊᝟ሗࡣ㸪ᚋࠎ࣓ࢱ᝟ሗ࡜
ࡋ࡚฼⏝ࡋࠊ㞟✚ࡉࢀࡓ㟢㢌᝟ሗࡢ᳨⣴ࡸศ㢮࡟฼⏝ࡍࡿࡇ࡜ࢆ᝿ᐃࡋ࡚࠸ࡿ㸬
୍᪉㸪ࠕࡌ࠾ࣟࢢࠖࡣ Web ࢧ࢖ࢺ࡛࠶ࡿᛶ㉁ୖࠊ㟢㢌᝟ሗࡢධຊࡣ Web ࣈࣛ࢘ࢨࢆ⏝࠸
ࡓ⏬ീࢹ࣮ࢱ㸪఩⨨᝟ሗ➼ࡢ࢔ࢵࣉ࣮ࣟࢻࡀᚲ㡲࡛࠶ࡿ㸬ࡑࡢࡓࡵ᧯సᛶ࡞࡝ࡢⅬ࠿ࡽ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⌧
ሙ࠿ࡽࢹ࣮ࢱࡢ࢔ࢵࣉ࣮ࣟࢻࡀ┤᥋⾜࠼ࡿࡇ࡜ࡀᮃࡲࡋ࠸㸬ࡑࡇ࡛ᡃࠎࡣ㸪ᒇእ࡟࠾ࡅࡿ㟢
㢌᝟ሗࡢ཰㞟ࢆ෇⁥࡟⾜࠼ࡿࡼ࠺ࢫ࣐࣮ࢺࣇ࢛ࣥ࠿ࡽ┤᥋㸪㟢㢌᝟ሗࡢⓏ㘓ࡀ⾜࠼ࡿ 2 ✀㢮
ࡢࣔࣂ࢖ࣝ࢔ࣉࣜࢣ࣮ࢩࣙࣥࡢ㛤Ⓨࢆ⾜ࡗࡓ㸬
Fig.1 㟢㢌᝟ሗࢧ࢖ࢺࠕࡌ࠾ࣟࢢࠖ Fig.2ࠕࡌ࠾ࣟࢢࠖᢞ✏⏝࢔ࣉࣜࢣ࣮ࢩࣙ
ࣥ
- 24 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 2-03 ◊✲ࢹ࣮ࢱඹ᭷ࡢࡓࡵࡢᆅ⌮᝟ሗࢹ࣮ࢱ࣮࣋ࢫࢧ࣮ࣅࢫࡢᵓ⠏
㧗ᶫఙᘺ㸦⚟ᒸ኱࣭ᕤ㸧࣭ዟᮧ ຾㸦⚟ᒸ኱࣭⥲ྜ᝟ሗฎ⌮ࢭࣥࢱ࣮㸧
㭯⏣┤அ㸦⚟ᒸ኱࣭ᕤ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⅏ࡸ࢔࢘ࢺ࣮ࣜࢳࡢ㠃࠿ࡽࡶ㠀ᖖ࡟㔜せ࡛࠶ࡿ㸬ᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ࡛ࡣ㟢㢌᝟ሗ
ඹ᭷ࡢⅭࡢ࢙࢘ࣈࢧ࢖ࢺࢆ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 ࢧ࢖ࢺࠕࡌ࠾ࣟࢢࠖ ࡸ㸪⤒⦋
ᗘ᝟ሗࡸ௵ពࡢ࣮࣮࢟࣡ࢻ࣭ࢥ࣓ࣥࢺࢆ㟢㢌⏬ീ࡟୍ᣓࡋ࡚௜୚ࡍࡿࢶ࣮ࣝࠕo-GIEࠖ࡞࡝
ࡢ㛤Ⓨࢆ⾜ࡗ࡚ࡁࡓ㸬
㟢㢌᝟ሗࡣᮏ㉁ⓗ࡟㠀ᐃᆺ࠿ࡘ⮬⏤ᗘࡢ㧗࠸ࢹ࣮ࢱ࡛࠶ࡿࡓࡵ㸪⦅㞟⪅࡟ࡼࡗ࡚⾲グࡸ⾲
⌧ࡀ␗࡞ࡿࡇ࡜ࡣከࠎ࠶ࡿ㸬ࡲࡓ㸪ࡑࢀࡽࢆᩚ⌮㸪ᵓ⠏ࡍࡿ࡟ࡣᑓ㛛ᐙ࡟ࡼࡿᡭసᴗࢆᚲせ
࡜ࡋ㸪⭾኱࡞ேⓗ࣭᫬㛫ⓗࢥࢫࢺࢆせࡍࡿࡇ࡜࡜࡞ࡿ㸬ࡇࡢၥ㢟࡟ᑐࡋ㸪฼⏝⪅ࡀࢹ࣮ࢱ࡟
௜୚ࡋࡓ௵ពࡢࢱࢢࢆ⏝࠸࡚⮬ືศ㢮ࡍࡿࡇ࡜࡟ࡼࡾࢹ࣮ࢱ࣮࣋ࢫసᡂࢆ┬ຊ໬ࡍࡿࡇ࡜ࢆ
⪃࠼ࡿ㸬ࢱࢢࢆ฼⏝ࡋࡓࢹ࣮ࢱ⟶⌮࡛ࡣ㸪⮬⏤࡟௵ពࡢ࣮࣮࢟࣡ࢻࢆ௜ຍࡍࡿࡇ࡜ࡀ࡛ࡁࡿ
ࡢ࡛㸪ࢹ࣮ࢱ㡯┠ࡢෆᐜࡸ㡯┠ᩘ㸪ࣇ࢛࣮࣐ࢵࢺ➼࡟㢌ࢆ↹ࢃࡏࡿࡇ࡜ࡀ࡞ࡃ㸪ࢱࢢ࡟ᇶ࡙
ࡃࢹ࣮ࢱ㛫ࡢ㢮ఝᗘィ⟬࡟ࡼࡾ⮬ືศ㢮ࡀྍ⬟࡜࡞ࡿࡓࡵ㸪஦๓ࡢศ㢮࣭ᩚ⌮ࡀ୙せ㸪࡜࠸
ࡗࡓ࣓ࣜࢵࢺࡀ࠶ࡿ㸬ࣇ࢓࢖ࣝࡢ✀㢮ࡸ఩⨨᝟ሗ࡞࡝㸪ᶵᲔⓗ࡟ฎ⌮࡛ࡁࡿ᝟ሗࡣ⮬ືⓗ࡟
ࢱࢢ௜ࡅࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡾ㸪ᡤ᭷⪅ࡸ࢔ࢡࢭࢫࣞ࣋ࣝࠊⓏ㘓᪥᫬ࠊ᭦᪂᪥᫬ࡣ㞃ࡋࢱࢢ
࡜ࡋ࡚ಖᣢࡍࡿ㸬ࡉࡽ࡟ࡣ㸪ධຊࡉࢀࡓࢥ࣓ࣥࢺ➼ࡢᩥ❶࠿ࡽ⮬ືⓗ࡟㐺ษ࡞࣮࣮࢟࣡ࢻࢆ
ᢳฟࡍࡿࡇ࡜࡛㸪ࢱࢢධຊࡢᡭ㛫ࢆ㍍ῶࡍࡿࡇ࡜ࡶ࡛ࡁࡿ㸬ࡲࡓ㸪ࢹ࣮ࢱࢆᚑ᮶ᆺࡢ㝵ᒙᵓ
㐀࡛ࡣ࡞ࡃࣇࣛࢵࢺ࡞ᵓ㐀࡜ࡋ࡚⟶⌮ࡍࡿࡇ࡜࠿ࡽ㸪≀⌮ⓗ࡞ࢹ࣮ࢱ⟶⌮ࡢᵓ㐀ࢆ⪃៖ࡍࡿ
ᚲせࡀ࡞ࡃ㸪኱つᶍศᩓࢹ࣮ࢱ⟶⌮ࢩࢫࢸ࣒࡜ࡋ࡚ᵓ⠏ྍ⬟࡞Ⅼࡶ࣓ࣜࢵࢺ࡜ࡋ࡚ᣲࡆࡽࢀ
ࡿ㸬
ࡇࡢࢱࢢ࡟ࡼࡿࢹ࣮ࢱ࣮࣋ࢫసᡂᡭἲࡢ᭷ຠᛶࢆ᳨ウࡍࡿࡓࡵ㸪ᆅ㉁Ꮫ◊✲ᐊ࡟࠾ࡅࡿ༞
ᴗ◊✲➼ࡢ㛵㐃ࢹ࣮ࢱࢆᑐ㇟࡜ࡋࡓࢹ࣮ࢱ⟶⌮ᨭ᥼ࢩࢫࢸ࣒ࢆ㛤Ⓨࡋࡓ㸬 ᆅ㉁Ꮫ◊✲ᐊ࡟
࠾࠸࡚㸪༞ᴗ◊✲➼࡛ࡲ࡜ࡵࡽࢀࡿ◊✲㈨ᩱࡣ⭾኱࡞ࡶࡢ࡜࡞ࡿࡇ࡜࠿ࡽ㸪ࡑࢀࡽࡢࢹ࣮ࢱ
- 25 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡢᩓ㐓ࢆ㜵ࡂ㸪࠿ࡘ෌฼⏝ࢆ෇⁥࡟ࡍࡿࡼ࠺࡞ࢹ࣮ࢱ⟶⌮ᡭἲࡢ☜❧ࡣ㔜せ࡞ㄢ㢟࡜࡞ࡿ㸬
ࡲࡓࢹ࣮ࢱࡢ✀㢮࡜ࡋ࡚ࡶ㸪෗┿ࡸ⏬ീࡔࡅ࡛ࡣ࡞ࡃྛ✀ࢻ࣓࢟ࣗࣥࢺࣇ࢓࢖ࣝࡸ ᐃ⤖ᯝ
ࡢ⏕ࢹ࣮ࢱ࡞࡝ከᒱ࡟ࢃࡓࡿ㸬ᮏ◊✲࡛ࡣ㸪ࡇࢀࡽࡢⅬࢆ⪃៖ࡋࡓࢹ࣮ࢱ⟶⌮ᨭ᥼ࢩࢫࢸ࣒
ࢆᵓ⠏ࡋ㸪ᐇ㝿ࡢ㐠⏝ࢆ㏻ࡋ࡚᪂ࡓ࡞ㄢ㢟ࡸᚲせ࡞ᶵ⬟ࢆ᳨ウࡍࡿ㸬
ࡲࡎࡣࠊᇶᮏᶵ⬟ࢆ⤌ࡳ㎸ࢇࡔࣉࣟࢺࢱ࢖ࣉࢩࢫࢸ࣒ࢆᐇ⿦ࡋ㸪ȕ ∧࡜ࡋ࡚ 2014 ᖺ 9
᭶࠿ࡽヨ⏝ࢆ㛤ጞࡋࡓ㸬ᐇ⿦ࡉࢀࡓᶵ⬟ࡢ࠺ࡕ୺࡞ࡶࡢ࡜ࡋ࡚ࡣ㸪 ࢱࢢ࡟ࡼࡿࣇ࢓࢖ࣝ⟶
⌮ᶵ⬟㸪 ྛ✀ࣇ࢓࢖ࣝ㸦⏬ീࣇ࢓࢖ࣝཬࡧ Word/Excel/PowerPoint/PDF ௚㸧ࢆ୍ᣓ⟶⌮ࡍࡿ
ᶵ⬟㸪 ┤ឤⓗ࡞᧯స࡟ࡼࡿࢱࢢ᳨⣴ᶵ⬟㸪 ఩⨨᝟ሗ࡜ࡢ⣣௜ࡅᶵ⬟࡞࡝ࡀ࠶ࡿ㸬
ᆅ㉁Ꮫ◊✲ᐊࡢ㛵ಀ⪅ࡽ㸴ྡࢆᑐ㇟࡜ࡋ࡚㸪ࡇࡢࣉࣟࢺࢱ࢖ࣉࢩࢫࢸ࣒ࢆヨ⏝ࡋ࡚ࡶࡽ
ࡗࡓ⤖ᯝ㸪཰㞟ࡉࢀࡓࢹ࣮ࢱ⥲ᩘࡣ 892 ಶ࡜࡞ࡗࡓ㸬࠺ࡕ⏬ീࡀ 630 ಶ࡛࠶ࡾ㸪ࡑࡢ௚
docx/xlsx ➼ࡢࣇ࢓࢖ࣝࡀ 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ᗘࡢ᭱኱್ࡣ 90 ᅇ࡛㸪10 ᅇ௨ୖ౑⏝ࡉࢀࡓࢱࢢࡣ 18 ✀࡛࠶ࡗ
ࡓ㸬㏫࡟ 3 ᅇ௨ୗࡢ౑⏝㢖ᗘࡢࢱࢢࡣ 13 ✀࡛࠶ࡗࡓ㸬
౑⏝⪅࠿ࡽࡢせᮃ࡜ࡋ࡚ࡣ㸪ࢱࢢࡢ⾲グࡢᦂࢀ࡟ᑐฎࡋ࡚࡯ࡋ࠸㸪ࢱࢢධຊࡢ㝿࡟⿵᏶ᶵ
⬟ࡀ࠶ࡿ࡜ࡼ࠸㸪⤒⦋ᗘ࠿ࡽᆅྡࢱࢢࢆ⮬ື࡛ࡘࡅࡽࢀ࡞࠸࠿㸪࡜࠸ࡗࡓࢱࢢධຊ࡟㛵ࡍࡿ
ࡶࡢࡀከࡃᣲࡆࡽࢀࡓ㸬ࡇࢀࡣ௒ᚋࡢᨵၿ㡯┠࡜ࡋ᳨࡚ウࡋ㸪㡰࡟ᶵ⬟㏣ຍ࣭ᨵⰋࢆ⾜ࡗ࡚
࠸ࡃணᐃ࡛࠶ࡿ㸬
- 26 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 2-04 ⅆᒣᄇⅆྐ᝟ሗࢹ࣮ࢱ࣮࣋ࢫࡢ 2 ḟ฼⏝࡟ࡘ࠸࡚
㭯⏣┤அ㸦⚟ᒸ኱࣭ᕤ㸧࣭㧗ᶫఙᘺ㸦⚟ᒸ኱࣭ᕤ㸧࣭
ዟᮧ ຾㸦⚟ᒸ኱࣭⥲ྜ᝟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㉁ࢹ࣮ࢱ࣮࣋ࢫ࡟ಖᏑࡉࢀࡓࢹ࣮ࢱࡢά⏝᪉ἲ࡟ࡘ࠸࡚⪃࠼ࡿ㸬◊✲⪅
ࡀ⮬㌟࡛㞟ࡵ࡚ࢹ࣮ࢱ࣮࣋ࢫ࡟ಖᏑࡋࡓࢹ࣮ࢱࢆ 1 ḟࢹ࣮ࢱ࡜࿧ࡪࡇ࡜࡟ࡋ࡚㸪1 ḟࢹ࣮ࢱ
ࢆ᳨⣴ࡋ࡞ࡀࡽㄽᩥࢆ᭩ࡃ࡜࠸ࡗࡓ฼⏝ᙧែࢆࢹ࣮ࢱࡢ 1 ḟ฼⏝࡜࿧ࡪࡇ࡜࡟ࡍࡿ㸬୍᪉㸪
◊✲ᶵ㛵ࡀබ㛤ࡉࢀ࡚࠸ࡿࢹ࣮ࢱࢆ኱㔞࡟㞟ࡵ㸦౛࠼ࡤ⤫ィⓗ࡞㸧ฎ⌮ࢆ᪋ࡋ࡚ᚓࡓࢹ࣮ࢱ
ࢆ 2 ḟࢹ࣮ࢱ࡜࿧ࡪࡇ࡜࡟ࡋ࡚ 2 ḟࢹ࣮ࢱࢆⓑ᭩ࡢ୍㒊࡜ࡋ࡚฼⏝ࡍࡿ࡜ゝࡗࡓ฼⏝ᙧែࢆ
2 ḟ฼⏝࡜࿧ࡪࡇ࡜࡟ࡍࡿ㸬1 ḟ฼⏝࡜ 2 ḟ฼⏝ࡢ㛵ಀࡣ㸪㠀බ㛤ࢹ࣮ࢱࡢ฼⏝࡜බ㛤ࢹ࣮ࢱ
ࡢ฼⏝ࡢ㛵ಀ࡜ࡣᚲࡎࡋࡶᑐᛂࡋ࡞࠸㸬౛࠼ࡤᑗ᮶ⓗ࡟ࡣ㸪◊✲┠ⓗ࡟㝈ࡗ࡚◊✲⪅ಶேࡢ
཰㞟ࢹ࣮ࢱࢆᗈࡃබ㛤ࡍࡿࡇ࡜ࡶ࠶ࡿ࡛࠶ࢁ࠺ࡋ㸪ඖࢹ࣮ࢱࢆබ㛤ࡋ࡞࠸ࡇ࡜ࢆ๓ᥦ࡟⤫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ఱࡽ࠿ࡢ ID ࢆ௜ຍ
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
䐢᭱᪂᝟ሗ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 -
ࢧ࣮ࣂ࡜ࢹ࢕ࣞࢡࢺࣜ㸪ࣇ࢓࢖
ࣝ ྡ ࢆ ౑ ࡗ ࡓ URI 㸦 Uniform
Resource Identifier㸧࡞࡝ࡀᛂ⏝࡛
ࡁࢀࡤຠ⋡ࡀⰋ࠸㸬୍᪉࡛㸪㠀බ
㛤ࡢ㸯ḟࢹ࣮ࢱ࠿ࡽ㸰ḟࢹ࣮ࢱ
ࢆ⏕ᡂࡍࡿ㝿ࡣ㸪㸰ḟࢹ࣮ࢱࡢ
⏕ᡂసᴗ୰࡟㠀බ㛤ࢹ࣮ࢱࢆ㎺
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡿࡇ࡜ࡀ࡛ࡁ࡞࠸ࡼ࠺࡟ࡍࡿᚲせࡀ࠶ࡿ㸬ࡇࢀ࡟ࡣ㸪ID ࡢ༏ྡ໬ࡢᢏ⾡ࡀᚲせ࡟࡞ࡿ㸬༏ྡ
໬࡜ࡣಶே᝟ሗࢆ㸰ḟ฼⏝ࡍࡿ㝿࡞࡝࡟ࡶ౑ࢃࢀ࡚࠸ࡿᢏ⾡࡛࠶ࡿ㸬ࡲࡓ㸪㟢㢌⏬ീࢆ⦋ᗘ
⤒ᗘ᳨࡛⣴ࡍࡿ࡜㸪᧜ᙳ᫬ᮇࡢ␗࡞ࡿ」ᩘࡢ⏬ീࡀᚓࡽࢀࡿࡇ࡜ࡀ⪃࠼ࡽࢀࡿ㸬ࡇࡢሙྜ㸪
࡝ࡕࡽࡀ᭱᪂ࡢ᝟ሗ࡛࠶ࡿ࠿ࡣ㔜せ࡞ࡢ࡛᧜ᙳ᫬ࡢࢱ࢖࣒ࢫࢱࣥࣉࢆࢹ࣮ࢱ࡟௜୚ࡋ࡚࠾ࡃ
ࡇ࡜ࡀᚲせ࡜࡞ࡿ㸬᭦࡟ࡣ㸪୙ṇ฼⏝ࡢᢚṆຠᯝࢆാ࠿ࡏࡿព࿡࡛㸪ࢹ࣮ࢱ࡬ࡢ࢔ࢡࢭࢫࣟ
ࢢࢆ୍ᐃᮇ㛫ಖᣢࡍࡿࡇ࡜ࡶᚲせ࡜࡞ࢁ࠺㸬
ḟ࡟㸪⏬ീฎ⌮ࢆ⏝࠸ࡓ 2 ḟ฼⏝ࢆど㔝࡟ධࢀࡓᢏ⾡㛤Ⓨࡢලయ౛ࢆ♧ࡍ㸬ࡇࡢᢏ⾡ࡣ஧
ࡘࡢせ⣲࠿ࡽ࡞ࡿ㸬୍ࡘ┠ࡣ㸪2 ḟ฼⏝ࢆᐜ᫆࡟ࡍࡿࡓࡵࡢ 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ࡲࡿࡇ࡜ࢆ᝿ᐃࡋ࡚㸪ࢧ࣮ࣂୖ࡛㟢㢌෗┿࠿ࡽ᩿ᒙ
ࡢೃ⿵࡜࡞ࡿட⿣ࢆ⮬ື᳨ฟࡋ㸪ࡑࡢ 3 ḟඖⓗ࡞ጼໃࢆ᥎ᐃࡍࡿࡇ࡜ࢆ┠ⓗ࡜ࡋ࡚࠸ࡿ㸦ࢱ
ࣈࣞࢵࢺ➃ᮎ࡞࡝࡟ᐇ⿦ࡍࢀࡤ㟢㢌ࡢ᧜ᙳ᫬࡟⌧ᆅ࡛ィ ࢆ῭ࡲࡏ㸪ィ ⤖ᯝࢆࢧ࣮ࣂ࡟࢔
ࢵࣉ࣮ࣟࢻࡍࡿ࢖ࣥࢱ࣮ࣇ࢙࢖ࢫ࣭ࢶ࣮ࣝ࡜ࡋ࡚ࡶ฼⏝࡛ࡁࡿ㸧
㸬ᅗ㸰࡟♧ࡍࡼ࠺࡟㸪ᆅ☢Ẽ
ࢭࣥࢧ࣮࡜ຍ㏿ᗘࢭࣥࢧ࣮ࢆෆⶶࡋࡓࢫ࣐࣮ࢺࣇ࢛ࣥ࡞࡝ࡢ࣓࡛࢝ࣛ㟢㢌ࢆື⏬᧜ᙳࡍࡿ
㸦a㸧㸬᧜ᙳ୰࡟࣓࢝ࣛࢆ⛣ືࡋ㸪ࢫࢸࣞ࢜ࣅࢪࣙࣥ࡟ࡼࡾ≉ᚩⅬࡢ୕ḟඖ఩⨨ࢆ࣓࢝ࣛ୰ᚰ
ᗙᶆ⣔࡛ィ ࡍࡿ㸦b㹼d㸧㸬ࡑࡢ㝿ࢭࣥࢧ࣮࠿ࡽᚓࡽࢀࡓ᝟ሗࢆࡶ࡜࡟࣓࢝ࣛࡢ఩⨨ጼໃࢆᆶ
┤㍈࡜⦋ᗘ⤒ᗘ࠿ࡽ࡞ࡿỈᖹ㍈࡟ࡼࡗ࡚ᵓᡂࡉࢀࡿᗙᶆ⣔㸦ࡇࢀࢆᮏ◊✲࡛ࡣᆅ⌫ᗙᶆ⣔࡜
࿧ࢇ࡛࠸ࡿ㸧࡛᥎ᐃࡋ࡚࠾ࡁ㸪≉ᚩⅬࡢ୕ḟඖᗙᶆ್ࢆᆅ⌫ᗙᶆ⣔࡟ኚ᥮ࡍࡿ㸬᭦࡟㟢㢌⏬
ീ࠿ࡽட⿣⥺ࢆ⏬ീ≉ᚩ࡜ࡋ࡚ᢳฟࡋ㸪ඛࡢ≉ᚩⅬࢆட⿣⥺ୖ࠶ࡿ࠸ࡣࡑࡢ࿘ᅖ㤳఩ࡢ≉ᚩ
Ⅼ࡟㝈ᐃࡍࡿ㸦e㸧㸬㝈ᐃࡋࡓ≉ᚩⅬࡢᗙᶆ್࠿ࡽ㸪ட⿣ࡢ᪉ྥࢆ᭱ᑠ஧஌᥎ᐃ࡟ࡼࡾ᥎ᐃࡍ
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ࡢࢩ࣮ࣥ࡟ᢞᙳࡍࡿࡇ
࡜࡟ࡼࡗ୍࡚⯡ᕷẸྥࡅࡢᏛ⩦ᩍᮦ࡜ࡋࡓࡾ㸪㟢㢌ࡢ෌ㄪᰝࢆᐜ᫆࡟ࡋࡓࡾࡍࡿࡇ࡜ࢆ┠ⓗ
࡜ࡋ࡚࠸ࡿ㸬≉Ṧ࡞࣐࣮࣮࢝ࢆᚲせ࡜ࡏࡎ㸪஦๓ࡢ㢼ᬒࡑࡢࡶࡢࢆ࣐࣮࣮࢝࡜ࡋ࡚฼⏝ࡍࡿ
࣐࣮࣮࢝ࣞࢫ᪉ᘧࡢ୍ࡘ PTAMM(Parallel Tracking And Multiple Mapping,
G. Klein࣭D.W.
Murray 2007)ࢆ᥇⏝ࡋ࡚࠸ࡿ㸬PTAMM ࡛ࡣ㸪๓㏙ࡢட⿣᳨ฟ࡜ྠࡌࢫࢸࣞ࢜どࡢཎ⌮ࢆ⏝࠸
࡚㸪ࢩ࣮ࣥ୰ࡢ≉ᚩⅬࡢ 3 ḟඖ఩⨨ࢆ᥎ᐃࡋ࡚࣐࣮࣮࢝ࡢ௦ࢃࡾ࡜ࡋ࡚グ᠈ࡍࡿ㸬ࡇࡢグ᠈
ࢹ࣮ࢱࢆ࣐ࢵࣉ࡜࿧ࡪ㸬ࡑࡢᚋࡣ㸪⌧ᅾࡢࢩ࣮ࣥ࠿ࡽᚓࡽࢀࡿ≉ᚩⅬࡢ 3 ḟඖ఩⨨࡜࣐ࢵࣉ
ࡢ≉ᚩⅬࡢ 3 ḟඖ఩⨨࡜ࢆ↷ྜࡋ࡚⌧ᅾࡢ࣓࢝ࣛࡢ఩⨨࣭ጼໃࢆ᥎ᐃࡋ㸪┠ⓗࡢ఩⨨࡟㹁㹅
ࢆ⾲♧ࡍࡿ㸬ᅗ㸱࡟ᅗ㸰࡛ᚓࡓட⿣ୖࡢ≉ᚩⅬࢆ㟢㢌ࢩ࣮ࣥ࡟㹁㹅໬ࡋ࡚㔜ࡡྜࢃࡏ⾲♧ࡋ
ࡓ౛ࢆ♧ࡍ㸬どⅬࢆኚ࠼࡚ࡶட⿣ࡢ఩⨨ࡀ≉ᐃ࡛ࡁ࡚࠸ࡿᵝᏊࡀࢃ࠿ࡿ㸬CG ໬ࡍࡿࢥࣥࢸࣥ
ࢶ࡜ࡋ࡚ࡣ㸪ㄝ᫂⏝ࡢ௬᝿ࣃࢿࣝࡸ࣒࣮ࣅ࣮ࢆ㔜ࡡ⾲♧ࡍࡿࡇ࡜࡞࡝ࡀ⪃࠼ࡽࢀࡿ㸬
- 28 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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)ட⿣᳨ฟ⤖ᯝ࡜≉ᚩⅬࡢ㑅ᢥ
(d)≉ᚩⅬࡢ୕ḟඖィ ⤖ᯝ
(f)ட⿣᪉ྥࡢ୕ḟඖィ ⤖ᯝ
ᅗ㸰㸬ட⿣⥺ࡢ㸱ḟඖ ᐃࡢฎ⌮㐣⛬
- 29 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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⏣బ჆ᚿ࣭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⏣బ჆ᚿ࣭஭ᡭ⩧኱࣭㭯⏣┤அ㸦2014㸧
㸸≉ᚩⅬᢳฟᡓ␎ࡢᨵⰋ࡟ࡼࡿ⮬↛⎔ቃࢆᑐ㇟࡜ࡋ
ࡓ PTAMM ࡢ఩⨨᥎ᐃ⬟ຊࡢྥୖ㸪ಙᏛᢏሗ, vol. 113, no. 431, PRMU2013-134, pp. 73-76㸬
- 30 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 3-01 ༡஑ᕞ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⏣࢝ࣝࢹࣛࡣ༡஑ᕞ㸪⸃ᦶ༙ᓥ༡➃࡟఩⨨ࡍࡿᑠᆺ㸦┤ᚄ⣙ 4 km㸧ࡢ࢝ࣝࢹ࡛ࣛ࠶ࡿ㸬
࢝ࣝࢹࣛᙧᡂᄇⅆࡣࡑࡢつᶍࡢ኱ࡁࡉ࠿ࡽᄇⅆ๓ࡢ᝟ሗࡀ࡯࡜ࢇ࡝ኻࢃࢀ࡚ࡋࡲ࠺ࡀ㸪ᑠᆺ
ࡢụ⏣࢝ࣝࢹࣛࡣ㸪ᄇⅆ๓ࡢ᝟ሗࡀẚ㍑ⓗಖᏑࡉࢀ࡚࠸ࡿ࢝ࣝࢹ࡛ࣛ࠶ࡿ㸬ᮏⓎ⾲࡛ࡣ㸪ヲ
⣽࡞ᆅ㉁ㄪᰝࢆࡶ࡜࡟㸪࢝ࣝࢹࣛᙧᡂᄇⅆࡢ‽ഛ㐣⛬ࢆྵࡵࡓụ⏣࢝ࣝࢹࣛࡢᄇⅆྐࢆ♧ࡍ㸬
ụ⏣࢝ࣝࢹࣛࡢάື࡟ඛ⾜ࡍࡿ⣙ 2 ୓ᖺ๓࡟ᒾᮏ㝆ୗⅆᒣ⅊ሁ✚≀ࢆᄇฟࡋࡓ㸬௝⏣⁐ᒾ
ࡶ㨣⏺࢝ࣝࢹࣛ㸦7.3 cal kBP㸧ࡢάືࡢ๓࡟ᄇฟࡋ࡚࠸ࡿ㸬6.4 cal kBP ࡢ࢝ࣝࢹࣛᙧᡂᄇⅆ
- 31 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 㸦Fig. 1㸧ࡣ㸪Ỉ⵨Ẽ⇿Ⓨ࡟ࡼࡾụᓮࢧ࣮ࢪሁ✚≀࣭㝆ୗⅆᒣ⅊ሁ✚≀ࡢᄇฟ࡟ࡼࡾ㛤ጞࡋ㸪
ࡑࡢᚋ࣐ࢢ࣐ᄇⅆ㸦୍㒊࣐ࢢ࣐Ỉ⵨Ẽᄇⅆࡶྵࡴ㸧࡟⛣⾜ࡋ㸪ᑿୗ㝆ୗࢫࢥࣜ࢔ሁ✚≀㸪Ỉ
㏕㝆ୗࢫࢥࣜ࢔ሁ✚≀ཬࡧụ⏣㝆ୗ㍍▼ሁ✚≀ࢆ┦ḟ࠸࡛ᄇฟࡋࡓ㸬᭱┒ᮇ࡟ࡣụ⏣ⅆ○ὶ
ሁ✚≀ࢆᄇฟࡋ㸪࢝ࣝࢹࣛࢆᙧᡂࡍࡿ࡜ࡶ࡟㸪ⅆ○ὶࡣᙜ᫬ࡢෆ‴ࢆᇙࡵ❧࡚⌧ᅾࡢⅆ○ὶ
ྎᆅࢆᙧᡂࡋࡓ㸬ࡇࡢ┤ᚋ㸪࢝ࣝࢹࣛࡢ༡す᪉ྥ࡟ḟࠎ࡜࣐࣮ࣝࢆᙧᡂࡋࡓ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ࡢᄇⅆࡢ᭱ᚋ࡟ࡣ㸪࢝ࣝࢹࣛᗏ࡛Ỉ⵨Ẽ࣐ࢢ࣐ᄇⅆࡀⓎ⏕ࡋ㸪ụ⏣†㝆ୗⅆᒣ⅊
ሁ✚≀ࢆᄇฟࡋࡓ㸬ࡇࡢᄇⅆࡢᮎᮇ࡟ࡣ⁐ᒾ෇㡬ୣࡀᙧᡂࡉࢀࡓ㸬ụ⏣†ⅆᒣ⅊ሁ✚ᚋ࡟ࡣ㸪
ἢᓊ㒊࡛ࡣụ⏣ⅆ○ὶሁ✚≀ࡢ஧ḟ⇿ⓎࡀⓎ⏕ࡋࡓ㸬ࡇࢀࡽࡢᄇⅆ࠿ࡽᩘ༓ᖺᚋ࡟෌ࡧ࢝ࣝ
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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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⁀ࡲࡾ࠿ࡽࡢᛴ㏿࡞࣐ࢢ࣐ࡢᄇฟ࡟ࡼࡗ࡚㸪࣐ࢢ࣐⁀ࡲࡾ
ෆࡢ࣐ࢢ࣐ᅽࡀపୗࡋ㸪ᨭᣢࢆኻࡗࡓ࣐ࢢ࣐⁀ࡲࡾኳ஭ࡀ࣐ࢢ࣐⁀ࡲࡾෆ࡟ỿ㝆ࡍࡿࡇ࡜࡟
ࡼࡗ࡚ᘬࡁ㉳ࡇࡉࢀࡿ㸬࣐ࢢ࣐⁀ࡲࡾኳ஭ࡢỿ㝆ࡣ㸪⎔≧᩿ᒙࡢᙧᡂ࡜ࡑࡢኚ఩࡟ࡼࡗ࡚つ
ไࡉࢀࡿ㸬ࡋࡓࡀࡗ࡚㸪㝗ἐ࢝ࣝࢹࣛࡢᙧᡂ࣓࢝ࢽࢬ࣒ࢆ⌮ゎࡍࡿࡓࡵ࡟ࡣ㸪࣐ࢢ࣐⁀ࡲࡾ
ࡢῶᅽ㐣⛬ࢆࢥࣥࢺ࣮ࣟࣝࡍࡿ“๓㥑ᄇⅆ”ࣉࣟࢭࢫࢆ⌮ゎࡋ࡞ࡅࢀࡤ࡞ࡽ࡞࠸㸬
㮵ඣᓥ┴ࡢጸⰋ࢝ࣝࢹࣛ࠿ࡽ⣙ 29,000 ᖺ๓࡟Ⓨ⏕ࡋࡓጸⰋ AT ᄇⅆࡣ㸪ᡃࡀᅜ࡟࠾࠸࡚ᚋ
ᮇ᭦᪂ୡ㹼᏶᪂ୡ࡟㉳ࡇࡗࡓ᭱኱⣭ࡢᄇⅆࡢ୍ࡘ࡛࠶ࡿ㸬ࡇࡢᄇⅆ࡟ࡼࡗ࡚ᄇฟࡋࡓධᡞⅆ
○ὶࡣ㸪஑ᕞᓥ༡㒊ࡢᗈ࠸⠊ᅖ࡟ᗈࡀࡗࡓ㸬ࡑࡢ⥲㔞ࡣ 350 ❧᪉ km ࡜᥎ ࡉࢀ࡚࠸ࡿ㸦ୖ
㔝㸪2001㸧
㸬ධᡞⅆ○ὶࡢᄇฟ࡟ඛ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࡜⪃࠼ࡽࢀࡿட๭ᆏゅ♟ᒙࡢᙧᡂ࡜ࡑࢀࢆそ࠺ධᡞⅆ○ὶࡢᄇฟ࡟⮳ࡗ
ࡓ㸬ᚑࡗ࡚㸪ጸⰋ AT ᄇⅆ࡟࠾ࡅࡿ࢝ࣝࢹࣛ㝗ἐࡣ㸪኱㝮㝆ୗ㍍▼ࡢᄇฟࢫࢸ࣮ࢪ࡟࠾ࡅࡿ
࣐ࢢ࣐ࡢ᤼ฟ࡜ࡑࢀ࡟ࡼࡿ࣐ࢢ࣐⁀ࡲࡾࡢῶᅽ࡟ࡼࡗ࡚ᘬࡁ㉳ࡇࡉࢀࡓ࡜⪃࠼ࡽࢀࡿ㸬
኱㝮㝆ୗ㍍▼ࡢᄇฟ㐣⛬ࢆ᳨ウࡍࡿࡓࡵ㸪ࡑࡢᒙᗎཬࡧᵓᡂ≀ࡢᆶ┤ኚ໬ࢆゎᯒࡋ࡚࠸
ࡿ㸬኱㝮㝆ୗ㍍▼ሁ✚≀࡟ࡣ┠❧ࡗࡓ㝆ୗࣘࢽࢵࢺࡣ(୍㒊ࡢࡸࡸ⣽⢏ࡢⷧᒙࢆ㝖࠸࡚)ㄆࡵ
ࡽࢀࡎ㸪඲඲య࡜ࡋ࡚ୖ᪉⢒⢏໬ࡍࡿ࡯ࡰ༢୍ࡢ㝆ୗࣘࢽࢵࢺࢆᵓᡂࡍࡿ㸦ᅗ 1㸧㸬ヲࡋࡃ
ぢࡿ࡜㸪ᅗ 1 ࡢᆅⅬ㸦ศᕸ୺㍈ୖ㸪ᱜᓥ࠿ࡽ⣙ 15km㸧࡛ࡣᇶᗏ࠿ࡽ⣙ 1m ࡢ㡿ᇦ࡛ࡣ㸪ࡑ
ࢀࡼࡾୖ㒊࡟ẚ࡭ࡿ࡜㍍▼⢏ᚄࡀᑠࡉࡃ㸪ୖ᪉࡟ྥ࠿ࡗ࡚ᛴ㏿࡟᭱኱⢏ᚄࡀቑຍࡍࡿ㸬ᇶᗏ
࠿ࡽ 1m ࡼࡾୖ఩࡛ࡣ㸪⣙ 4m ௜㏆࡟ཌࡉ 0.2m ࡢࡸࡸ⣽⢏ࡢᒙࢆᣳࡴࡶࡢࡢ㸪඲య࡜ࡋ࡚⦆
ࡸ࠿࡟᭱኱⢏ᚄࡀቑຍࡍࡿ㸬ࡇࡢࡼ࠺࡞᭱኱⢏ᚄࡢୖ᪉⢒⢏໬ࡣ㸪኱㝮㝆ୗ㍍▼ศᕸᇦࡢ࡯
ࡰ඲ᇦ࡛ほᐹࡉࢀࡿ㸦Kobayashi et al., 1983㸧
㸬㝆ୗ㍍▼ࡢ᭱኱⢏ᚄࡣᄇ↮㧗ᗘ࡟౫Ꮡࡋ㸪ᄇ
↮㧗ᗘࡣᄇฟ⋡ࡢ 1/4 ஌࡟ẚ౛ࡍࡿ㸦ref㸧ࡓࡵ㸪኱㝮㝆ୗ㍍▼඲య࡟ࡳࡽࢀࡿୖ᪉⢒⢏໬
ࡣ㸪኱㝮㍍▼ࡢᄇฟ⋡ࡀᄇⅆࡢ㐍⾜࡟ࡘࢀ࡚ቑຍࡋࡓࡇ࡜ࢆ♧ࡋ࡚࠸ࡿ㸬
୍᪉㸪኱㝮㝆ୗ㍍▼࡟ྵࡲࢀࡿ␗㉁ᒾ∦ࡣⅆ㐨ࡢᣑ኱㐣⛬ࢆ཯ᫎࡋ࡚࠸ࡿ㸬኱㝮㝆ୗ㍍▼
- 33 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡟ྵࡲࢀࡿ␗㉁ᒾ∦ࡣ㸪୺࡟ᆅ⾲௜㏆࡟Ꮡᅾࡋ࡚࠸ࡓ࡜⪃࠼ࡽࢀࡿᏳᒣᒾ㹼ࢹ࢖ࢧ࢖ࢺ⁐ᒾ
∦࡜㸪ጸⰋ࢝ࣝࢹࣛࡢᇶ┙ࢆᵓᡂࡍࡿᅄ୓༑ᒙ⩌࠿ࡽࡶࡓࡽࡉࢀࡓ㡫ᒾཬࡧ⣽⢏ࡢ◁ᒾ࠿ࡽ
࡞ࡿ㸬␗㉁ᒾ∦ࡢྵ᭷㔞ࡣ㸪኱㝮㝆ୗ㍍▼ࡢ඲యࢆ㏻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
∦࡜ࡋ࡚ᄇฟࡋࡓࡇ࡜ࢆ♧ࡋ࡚࠸ࡿ㸬
኱㝮㝆ୗ㍍▼࡛ࡣ㸪ⅆ㐨ቨࡢ኱つᶍ࡞౵㣗࡜ࡑࢀ࡟ࡼࡿⅆ㐨ᚄࡢᣑ኱࡟ࡼࡾ㸪㧗࠸ᄇฟ⋡
ࢆ⥔ᣢࡋ⥆ࡅࡿࡇ࡜ࡀྍ⬟࡜࡞ࡗࡓ࡜᥎ ࡉࢀࡿ㸬ጸⰋ࢝ࣝࢹࣛ࠿ࡽⓎ⏕ࡋࡓ࡯࠿ࡢ㍍▼ᄇ
ⅆ࡛ࡣ㸪␗㉁ᒾ∦ࡢྵ᭷㔞ࡣ኱㝮㝆ୗ㍍▼࡟ẚ࡭࡚ᑠࡉࡃ㸪ᇶ┙ᒾࡢ኱つᶍ࡞౵㣗ࡣㄆࡵࡽ
ࢀ࡞࠸㸬ࡇࡢࡇ࡜࠿ࡽ㸪࢝ࣝࢹࣛ㝗ἐ࡟⮳ࡿ༑ศ࡞࣐ࢢ࣐⁀ࡲࡾࡢῶᅽࢆࡶࡓࡽࡍ኱つᶍ࡞
࣐ࢢ࣐ᄇฟࡣ㸪ⅆ㐨ࡢᣑ኱ࣉࣟࢭࢫ࡟ࡼࡗ࡚ࢥࣥࢺ࣮ࣟࣝࡉࢀ࡚࠸ࡿࡇ࡜ࢆ♧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ᱜᓥ࠿ࡽ༡ᮾ⣙ 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┤ኚ໬࠿ࡽぢࡓධᡞⅆ○ὶࡢሁ✚ᶵᵓ㸬ⅆᒣ㸪46,
257-268㸬
3-03 㝗ἐ࢝ࣝࢹࣛࡢᄇฟ㔞࡜࣐ࢢ࣐⁀ࡾࡢ‽ഛᮇ㛫
- 34 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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)
࢝ࣝࢹࣛ࡜ࡑࡢ㝗ἐᵓ㐀ࡣ㸪ᆅୗ࡟Ꮡᅾࡍࡿᕧ኱࣐ࢢ࣐⁀ࡾ࡜㛵ಀࡀ῝࠸࡜࠸ࢃࢀࡿ (e.g.,
Gayer and Martí, 2008; Sobradelo et al., 2010)㸬ᕧ኱ᄇⅆ࡛ᨺฟࡉࢀࡿ࣐ࢢ࣐ࡢᄇฟ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࠸࡚ࡣⰋࡃࢃ࠿ࡗ࡚࠸࡞࠸㸬
࢝ࣝࢹࣛᚄ࡜ኚᙧ࣮ࣔࢻ㸸㝗ἐᗋࡢኚᙧ࣮ࣔࢻࡣⅆ㐨ࡢศᕸࢆᨭ㓄ࡍࡿࡓࡵ㸪ᄇฟ㔞࣭ᄇฟ
ᵝᘧ࡟ᙳ㡪ࡀ኱ࡁ࠸࡜᥎ᐹࡉࢀࡿ㸬ᆅẆࡢ᩿㠃࡟࠾࠸࡚㸪࢝ࣝࢹࣛࡢ┤ᚄ (Sc)࡜࣐ࢢ࣐⁀ࡾ
ኳ஭ࡢ῝ࡉ (D) ࡢẚࡣ Roof aspect ratio ࡜ᐃ⩏ࡉࢀ (RAR = D/Sc: Roche et al., 2000)㸪1 ᗘࡢ㝗
ἐ࡟క࠺ኚᙧ࣮ࣔࢻࡣ㸪RAR ࡟ࡼࡗ࡚ኚ໬ࡍࡿ࡜ࡉࢀࡿ (e.g., Roche et al., 2000; Acocella et al.,
2000)㸬㝗ἐᗋࡢኚᙧࢆ࡟࡞࠺ᵓ㐀せ⣲ࢆᘬᙇ๭ࢀ┠ࡸ᩿ᒙ➼ࡢ୙㐃⥆㠃࡜ࡳ࡞ࡋࡓሙྜ㸪኱
—ᑠつᶍ᩿ᒙࡢ๭ྜࢆ⾲ࡍ⣼✚㢖ᗘศᕸࡣࠕ࡭ࡁ஌๎ࠖ࡟ᚑ࠺࡜ண᝿ࡉࢀࡿࡓࡵ㸪㈇ࡢഴࡁ
ࢆ♧ࡍ࡭ࡁᣦᩘࡀ㸪㝗ἐᗋࡢኚᙧ࣮ࣔࢻࢆ⾲ࡍ㸬㈇ࡢഴࡁࡀ኱ࡁ࠸࡯࡝㸪ᑠつᶍ᩿ᒙࡢᐤ୚
⋡ࡀ㧗ࡃ㸪᩿ᒙ⩌ࡢ⥲⾲㠃✚ࡀ኱ࡁ࠸ኚᙧ㸪ࡍ࡞ࢃࡕᘏᛶⓗኚᙧ࡜࡞ࡿ㸬ྠࡌᚄࢧ࢖ࢬ࡛ኚ
ᙧࡀ␗࡞ࡿ࢝ࣝࢹࣛࢆẚ㍑ࡍࡿ࡜㸪RAR ࡀ኱ࡁࡃ᩿ᒙ⾲㠃✚ࡀ኱ࡁ࠸ኚᙧ࣮ࣔࢻࢆ㉳ࡇࡍ࢝
ࣝࢹࣛᄇⅆࡣ㸪ኚᙧ࡟ᑐࡍࡿෆ㒊 (⇕) ࢚ࢿࣝࢠ࣮ศ㓄ࡀ኱ࡁ࠸࡜࠸࠼ࡿ㸬୍᪉㸪ᄇฟ≀࠿ࡽ
ෆ㒊࢚ࢿࣝࢠ࣮ࢆぢ✚ࡾ㸪ྠ࢚ࢿࣝࢠ࣮┦ᙜࡢ᰾⇿Ⓨ࡜ẚ㍑ࡍࡿ࡜㸪኱ᆺࡢ࢝ࣝࢹࣛ࡯࡝ࡑ
ࡢᚄࡀ᭷ព࡟኱ࡁ࠸ (Scandone, 1990)㸬ࡇࡢࡇ࡜࠿ࡽ㸪኱ᆺࡢ࢝ࣝࢹ࡛ࣛࡣຠ⋡ⓗ࡞ኚᙧ࣮ࣔ
- 35 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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ᕧ኱ᄇⅆࡢ࿘ᮇᛶࢆ᥎ ࡍࡿࡓࡵ࡟ࡣ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࡟୙☜ᐇᛶࡀ኱ࡁࡃ㸪ࡲࡓ㸪ᕧ኱ᄇⅆࡢ࿘ᮇᛶࢆ୍⯡໬ࡍࡿ࡯࡝඘ᐇࡋ࡚࠸࡞࠸ (Deligne
et al., 2010)㸬᪤࡟άືࢆ⤊࠼ࡓ࢝ࣝࢹࣛⅆᒣ⩌࡛ࡣ㸪㝵ẁᅗ࡟࠾࠸࡚ᕧ኱ᄇⅆࡢ࿘ᮇᛶࢆ㆟ㄽ
ࡋࡓ౛ࡀ࠶ࡾ (Salisbury et al., 2011)㸪㝵ẁᅗࢆ≀⌮໬Ꮫⓗ࡟ࣔࢹࣝ໬ࡍࡿࡇ࡜ࡶ㔜せ࡛࠶ࡿ㸬
ᕧ኱ᄇⅆࡢఇṆᮇ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⣧࡞ᙎᛶࣔࢹ࡛ࣝㄝ᫂ࡋࡓ౛ࡀ࠶ࡿ (Miura et al., 2013: Fig. 2)㸬ᕧ኱࣐ࢢ࣐⁀ࡾ࡛ࡣ⇕
㔞ࡀ኱ࡁ࠸ࡓࡵ㸪ᆅẆࡢᘏᛶⓗ᣺ࡿ⯙࠸ࢆ⪃៖࡟ධࢀ࡚ࣔࢹࣝ໬ࡉࢀࡿᚲ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⤒ࡿࣔࢹࣝࡀᥦ᱌ࡉ
ࢀ࡚࠸ࡿ (e.g., Annen, 2009)㸬LA-ICP-MS ࢆ⏝࠸ࡓ U-Pb ᖺ௦ ᐃἲ࡟ࡼࡾ㸪㯮㒊ᕝⰼᓵᒾయ
୰࡟」ᩘࡢ࣐ࢢ࣐㈏ධ࢖࣋ࣥࢺࡀ㆑ูࡉࢀࡓ౛ࡀ࠶ࡿ (Ito et al., 2013)㸬ࡇࢀࡽࡢ◊✲ࡸ㸪ࡉ
ࡽ࡟ᵝࠎ࡞ᡭἲࢆ⤌ྜࡏ㸪⥲ྜⓗ࡟࣐ࢢ࣐౪⤥⣔ࡢ㐍໬ࢆ⌮ゎࡍࡿࡇ࡜ࡀ୙ྍḞ࡛࠶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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 3-04 㧗⢭ᗘᆅ㟈Ἴࢺࣔࢢࣛࣇ࢕࣮࠿ࡽぢࡓάⅆᒣୗࡢ῝㒊ᵓ㐀
㉿ ኱㭉㸦ᮾ໭኱࣭⌮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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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⇃ᮏ኱࣭⮬↛⛉Ꮫ㸧࣭Ᏻ⏣ ᩔ㸦ᮾி኱ᆅ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◊✲⪅࡟ࡼࡗ࡚᫂ࡽ࠿࡟ࡉࢀ࡚࠾ࡾ㸪ᕧ኱ⅆ○ᄇⅆࡢ᥎⛣ࢆ◊✲ࡍ
ࡿ࡟ࡣ᭱㐺࡛࠶ࡿ㸬ࡲࡓ࢝ࣝࢹࣛእ࡛ࡣᕧ኱ⅆ○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⤌ᡂኚ໬ࢆሗ࿌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ᘚ฼ࢫࢥࣜ࢔ὶሁ✚≀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⇃ᮏ኱Ꮫ⌮Ꮫ㒊࠾ࡼࡧᮾி኱Ꮫᆅ㟈◊ࡢ EPMA ࡟ࡼࡗ࡚
໬Ꮫศᯒࢆ⾜ࡗࡓ㸬ࡲࡓᮾி኱Ꮫᆅ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࡜ᒙᗎ࡟ᚑࡗ࡚ࢃࡎ࠿࡛ࡣ࠶ࡿࡀቑຍࡍࡿഴྥࡀぢ
ࡽࢀࡿ㸬ࡲࡓ⤌ᡂศᕸࡶ༢୍ࣆ࣮ࢡ㸦⫧⊦㸧࠿ࡽ㧗 An ഃ࡟ᙅ࠸ࣆ࣮ࢡࢆᣢࡘࡶࡢ㸦ᑠ㇂㸪
ඵዪ㸪ᘚ฼㸧࡟ኚ໬ࡋ࡚࠸ࡁ㸪ᩳ㛗▼⤌ᡂࡢᖜࡀࡼࡾᗈࡃ࡞ࡿ㸦ᘚ฼㸧
㸬ࢥ࢔࡜࣒ࣜ࡟ศࡅ
࡚ศᯒࡋࡓࡀ㸪᫂ࡽ࠿࡞㏫⣼ᖏᵓ㐀ࡣぢࡘ࠿ࡽ࡞࠿ࡗࡓ㸬
඲ᒾ໬Ꮫ⤌ᡂ࡛ࡣ⫧⊦㸪ᑠ㇂㸪ඵዪ㸪ᘚ฼㸦㍍▼㸧ࡣ SiO2=68~70%࡟㞟୰ࡋ࡚࠾ࡾ㸪⤌
ᡂࡢ㐪࠸ࡣㄆࡵࡽࢀ࡞࠸㸬ࡋ࠿ࡋ㸪ᩳ㛗▼㸪ᩳ᪉㍤▼ᩬᬗ࡟ྵࡲࢀࡿ࣓ࣝࢺໟ᭷≀ࡢ࢞ࣛࢫ
࡛ࡣ㸪ศᯒࡋࡓ⫧⊦࡜ᑠ㇂ࡢ㛫࡛᫂░࡞㐪࠸ࡀㄆࡵࡽࢀࡓ㸬⫧⊦ࡢ࣓ࣝࢺໟ᭷≀ࡣ
SiO2=73~74%ࡢ⊃࠸⤌ᡂ㡿ᇦ࡟ศᕸࡍࡿࡀ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✚≀
ࡢ࢞ࣛࢫ࡟ᑐᛂࡍࡿࡇ࡜ࢆ㆟ㄽࡋࡓ㸬᳝ཎ㸦2014㸧ࡢඵዪࡀ㸪ᮏㄽࡢᑠ㇂࡜ఝ㏻ࡗࡓ⤌ᡂࢆ
- 39 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ♧ࡍࡇ࡜࠿ࡽ㸪༡࠾ࡼࡧす᪉࡟ὶࢀࡓᑠ㇂ⅆ○ὶ࡜໭᪉࡟ὶࢀࡓඵዪⅆ○ὶࡀ㸪࡯ࡰྠࡌ࣐
ࢢ࣐౪⤥⣔⏤᮶࡛࠶ࡿࡇ࡜ࡀ᥎ᐹࡉࢀࡿ㸬
ྵỈ㔞ࡣ⫧⊦ࡢ࣓ࣝࢺໟ᭷≀ࡣ 4%௨ୖ㸪ࢩࣜ࢝࡟ࡸࡸஈࡋ࠸ᑠ㇂࢞ࣛࢫໟ᭷≀ࡣ
2~4%࡛࠶ࡗࡓ㸬ሷ⣲⃰ᗘࡣ⫧⊦ࡢ࣓ࣝࢺໟ᭷≀ࡢ᪉ࡀᑠ㇂ࡼࡾ㧗࠸ࡀ㸪◲㯤ࡣࢩࣜ࢝࡟ஈ
ࡋ࠸ᑠ㇂ࡢ᪉ࡀࡸࡸ㧗࠸ྵ᭷㔞ࢆ♧ࡍ㸬
௨ୖࢆࡲ࡜ࡵࡿ࡜㸪⫧⊦ࡣ 1 ࡘࡢ࣐ࢢ࣐ᾮ┦ࢆ㸪ᑠ㇂㸪ඵዪ㸪ᘚ฼ࡣ 2 ࡘࡢ࣐ࢢ࣐ᾮ┦ࢆ
௦⾲ࡍࡿ࡜⪃࠼ࡽࢀࡿ㸬⫧⊦ᄇฟ᫬ࡣ࣐ࢢ࣐ᾮ┦㒊ศࡀᆒ㉁࡛࠶ࡾ㸪ᩳ㛗▼ࡣࡑࢀ࡜ᖹ⾮࡛
࠶ࡗࡓ࡜⪃࠼ࡽࢀࡿ㸬ࡇࢀ࡟ᑐࡋ㸪ᑠ㇂㸪ඵዪ㸪ᘚ฼࡛ࡣ」ᩘࡢ࣐ࢢ࣐ᾮ┦࡜ࡑࢀࡽ࡟ᖹ⾮
࡞ᩳ㛗▼ࡀᏑᅾࡍࡿ㸬ࡇࢀࡽࡢࢹ࣮ࢱࢆ᭱ࡶㄝ᫂ࡋࡸࡍ࠸ࣔࢹࣝࡣᡂᒙ࣐ࢢ࣐⁀ࡲࡾࡢୖᒙ
࠿ࡽࡢẁ㝵ⓗ࡞࣐ࢢ࣐᤼ฟ㸪ΰྜ࡛࠶ࢁ࠺㸬
- 40 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 3-06 㨣⏺࢝ࣝࢹࣛࡢ࢔࢝࣍ࣖᄇⅆ
ᑠᯘဴኵ㸦㮵ඣᓥ኱Ꮫ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┴⸃ᦶ༙ᓥ࠿ࡽ༡᪉࡬⣙50 km࡟఩⨨ࡍࡿᾏᗏ࢝ࣝࢹ࡛ࣛ࠶ࡾ㸪
ࡇࡇ࡛ࡣ7.3 cal kBP㸦ዟ㔝㸪2002㸧࡟㨣⏺࢔࢝࣍ࣖᄇⅆୗ఩࡜ࡼࡤࢀࡿ኱つᶍ࡞࢝ࣝࢹࣛᙧᡂ
ᄇⅆࡀⓎ⏕ࡋࡓ㸬ᄇⅆࡣ๓༙ࡢࣉࣜࢽ࣮ᘧᄇⅆ࡜ᚋ༙ࡢ኱つᶍⅆ○ὶᄇⅆ࡜ᘬࡁ⥆ࡃ࢝ࣝࢹ
ࣛᙧᡂ࠿ࡽ࡞ࡾ㸪ࡑࢀࡽࡣ㐃⥆ࡋ࡚Ⓨ⏕ࡋࡓ࡜᥎ᐃࡉࢀࡿ㸦ᑠ㔝࣭௚㸪1982㸹Maeno and Taniguchi,
2007㸧
㸬๓༙ࡢࣉࣜࢽ࣮ᘧᄇⅆࡢ⤊ᮎ࡟ࡣᄇ↮୰ᔂቯ࡟ࡼࡾ㧗 ࡢ⯪಴ⅆ○ὶࡀⓎ⏕ࡋࡓ㸬ᚋ
༙ࡢᄇⅆ࡛ࡣ⸃ᦶ࣭኱㝮༙ᓥ࡟ศᕸࡍࡿᖾᒇ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ᮾ໭ᆅ᪉ࡲ࡛ศᕸࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸬ᖾᒇ㝆ୗ㍍▼ࡣ⣙20km㸱㸪
ᖾᒇⅆ○ὶሁ✚≀ࡣ⣙50km㸱㸪㨣⏺࢔࢝࣍ࣖⅆᒣ⅊ࡣ100km㸱௨ୖ࡜᥎ᐃࡉࢀ࡚࠸ࡿ㸦⏫⏣࣭
᪂஭㸪2003㸧
㸬୍㐃ࡢᄇฟ≀ࡣ㨣⏺࢔࢝࣍ࣖࢸࣇࣛ࡜⛠ࡉࢀ࡚࠸ࡿ㸬
㸰 ᖾᒇⅆ○ὶࡢ฿㐩⠊ᅖ
Ky ࡣᴟࡵ࡚ⷧࡃᣑࡀࡗࡓࡀ㸪ࡑࡢ⠊ᅖ࡟ࡘ࠸࡚༡ഃࡣࢺ࢝ࣛิᓥ໭㒊㸪໭ഃࡣ⸃ᦶ༙ᓥ୰
㒊ࡢ㮵ඣᓥᕷ႐ධ࡜኱㝮༙ᓥࡢᚿᕸᚿࢆ⤖ࡪ⥺௨༡࡜ࡉࢀ࡚ࡁࡓ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ࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓ㸬ࡲࡓ㸪ࢺ࢝ࣛิᓥཱྀஅᓥ࡟ࡶ฿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✚ࡀㄆࡵࡽࢀࡿࡇ࡜࠿ࡽ㸪Ky ࡣᒣᆅࢆ
㉺࠼ࡿࡇ࡜ࡀ࡛ࡁ࡞࠿ࡗࡓ࡜⪃࠼ࡽࢀࡿ㸬
୍᪉㸪኱㝮༙ᓥ୰㒊ࡢ㮵ඣᓥ‴࡟㠃ࡋࡓ㮵ᒇᕷ㧗㡲ࡸⰼᒸ࡛ࡣ㸪ࢃࡎ࠿࡛࠶ࡿࡀⰋࡃⓎἻ
ࡋࡓᩘ cm ኱ࡢ㍍▼ࡀⅬᅾࡍࡿࡇ࡜࠿ࡽ㸪Ky ࡣ฿㐩ࡋࡓ࡜⤖ㄽ࡙ࡅࡽࢀࡿ㸬Ky ࡣ㮵ඣᓥ‴ἢ
࠸࡟ᾏୖࢆ໭ୖࡋ㸪‴࡟ἢࡗࡓ༙ᓥࡢᩳ㠃ࢆὶ㉮ࡋ㥑ࡅୖࡗࡓࡶࡢ࡛࠶ࢁ࠺㸬
ᮾࢩࢼᾏഃࡢ⸃ᦶ༙ᓥ࡛ࡣ㸪᪥⨨ᕷ྿ୖ༡㒊ࡲ࡛ Ky ࡀ☜ㄆࡉࢀࡿࡀ㸪ࡑࢀࡼࡾ௨໭࡛ࡣ
K-Ah ࡢࡳࡀሁ✚ࡍࡿ㸬㮵ඣᓥ‴ἢ࠸࡛ࡣ㮵ඣᓥᕷ႐ධࡢ໭㒊ࡲ࡛ Ky ࡀሁ✚ࡋ㸪ᶆ㧗 500m
- 41 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ௨ୖࡢᒣᆅ࡟ࡶሁ✚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ࡉࡽ࡟ࡑࢀ௨
๓࡟ࡣ㛗ᮇ࡟ࢃࡓࡿ᩿⥆ⓗ࡞ᄇⅆࡢ⏘≀࡛࠶ࡿ⡲ ࢸࣇࣛࡢᄇฟࡀ࠶ࡗࡓ㸦ዟ㔝࡯࠿㸪㸧
㸬
㨣⏺࢔࢝࣍ࣖᄇⅆ࡛ࡣ㸪๓༙ࡢࣉࣜࢽ࣮ᘧᄇⅆ┤ᚋ࠾ࡼࡧᚋ༙ࡢⅆ○ὶᄇⅆ࣭࢝ࣝࢹࣛᙧ
ᡂᮇࡢ㸰ᗘ࡟ࢃࡓࡗ࡚኱ᆅ㟈ࡀⓎ⏕ࡋࡓ㸦ᡂᑿ࣭ᑠᯘ㸪2002㸧
㸬
✀Ꮚᓥ࠾ࡼࡧᒇஂᓥ࡛ࡣ᭦᪂ୡᚋᮇࡢẁୣ♟ᒙ࠿ࡽୖ᪼ࡍࡿᄇ♟⬦ࡢᏑᅾࡍࡿ㸬ᄇ♟⬦ࡣ
Ky ┤ୗ࡟㐩ࡍࡿࡀ㸪Ky ࢆ㈏ࡃࡶࡢࡣぢࡽࢀ࡞࠸ࠋKy-p ┤ୗࡢᅵተᒙࡀ Ky-p ୰࡟ୖ᪼ࡍࡿ
౛㸪ᆅ๭ࢀ࡟ Ky ࡢࢢࣛࣥࢻࣞ࢖࣮ࣖࡀධࡾ㎸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࠸ࡿ౛ࡀከᩘᏑᅾࡍࡿ㸬ᄇ◁ࡣ K-Ah
ᒙࡢୗഃ 1/㸱⛬ᗘࡢ఩⨨࡛ᶓ࡟ᗈࡀࡾ㸪K-Ah ࡢ㝆ୗ㏵୰࡛ᆅ㟈ࡀⓎ⏕ࡋࡓࡇ࡜ࡣ␲࠸࡞࠸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࠸㟈ືࢆཷࡅࡓࡇ࡜ࢆ♧ࡋ࡚࠸ࡿ㸬㟈ືࡢⓎ⏕ࡋࡓ᫬
ᮇ࡟ࡘ࠸࡚ࡣ≉ᐃࡀ㞴ࡋ࠸ࡀ㸪K-Ah ᒙୖ㒊ࡀỈᖹ࡛࠶ࡿࡇ࡜࠿ࡽࡍࡿ࡜㸪K-Ah 㝆ୗ㏵୰࡛
Ⓨ⏕ࡋࡓᆅ㟈࡟ࡼࡿࡶࡢ࠿ࡶࡋࢀ࡞࠸㸬
ⅆ○ὶ࡟ࡼࡾᶞᮌࡀᶓ㌿ࡍࡿࡇ࡜ࡣᱜᓥࡢ኱ṇᄇⅆ࡞࡝࡛ࡶ▱ࡽࢀ࡚࠸ࡿࡀ㸪ᶞᮌ࡜࡜ࡶ
࡟ᆅᒙࡀᶓ㌿ࡍࡿ౛ࡀ 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᪉ྥࡣ࡯ࡰ໭࡛࠶ࡾ㸪㨣⏺࢝ࣝࢹࣛ࡜཯ᑐ᪉ྥ࡛࠶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○ὶᄇⅆ࣭࢝ࣝࢹࣛᙧᡂᮇ࡟ࡣᕧ኱ὠἼࡀⓎ⏕ࡋࡓྍ⬟ᛶࡀᣦ᦬ࡉࢀ࡚࠸ࡿ㸦⸨ཎ࣭
௚㸪2010㸹ᑠᯘ㸪2008㸹Maeno and Imamura, 2007 ࡞࡝㸧㸬
ᒇஂᓥ࡛ࡣ Ky ୰࡟ᶞᮌࡀྵࡲࢀࡿ౛ࡀከᩘ࠶ࡿࡀ㸪࠸ࡎࢀࡢᶞᮌࡶⅣ໬ࡋ࡚࠸࡞࠸㸬ࡲ
ࡓ㸪ᐑஅᾆᕝࡸᏳᡣᕝἢ࠸࡛ࡣ Ky ୰࡟◁ࡸ♟ࡀධࡾ㎸ࡴ౛ࡀ࠶ࡾ㸪ᑠ℩⏣ࡢᾏᓊ࡛ࡣ♟ᒙ୰
࡟ Ky ࡢ୍ḟሁ✚≀ࡀᣳࡲࡗ࡚࠸ࡿ㸬ࡇࢀࡽࡢ㉳※࡟ࡘ࠸࡚ࡣ Ky ሁ✚ᚋࡢࣛࣁ࣮ࣝሁ✚≀ࡢ
ྍ⬟ᛶ㸪ὠἼሁ✚≀ࡢྍ⬟ᛶ࡟ࡘ࠸࡚㸪௒ᚋ㸪ヲ⣽࡟᳨ウࡋ࡚࠸ࡃணᐃ࡛࠶ࡿ㸬
- 42 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 3-07 ᱜᓥⅆᒣࡢᄇⅆྐ࠿ࡽࡳࡓ⸃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 ᖺᚋ࡟᭱ึࡢࣉࣜࢽ࣮ᘧᄇⅆ
㸦P17㸧ࢆ㛤ጞࡋ࡚࠸ࡿ㸦Okuno et al., 1997㸧
㸬ᱜᓥࡢᄇⅆྐࡣ㸪ྂᮇ໭ᓅ㸪᪂ᮇ໭ᓅ㸪༡ᓅ࡟
㸱ࡘ࡟ࢫࢸ࣮ࢪ༊ศ࡛ࡁࡿࡀ㸪ᑠᯘ࡯࠿㸦2013㸧ࡣṔྐ᫬௦ࡢኳᖹᐆᏐ㸦764ࠥ766㸧
㸪ᩥ᫂㸦1471
ࠥ1476㸧
㸪ᏳỌ㸦1779㸧
㸪኱ṇ㸦1914㸧ࡢ኱つᶍ࡞ࣉࣜࢽ࣮ᘧᄇⅆࢆ୰ᚰ࡜ࡋࡓάືࢆ㸪᪂ᮇ༡
ᓅࢫࢸ࣮ࢪ࡜ࡋ࡚⊂❧ࡉࡏࡓ㸬2015 ᖺ⌧ᅾࡶ㸪᫛࿴ⅆཱྀࢆ୰ᚰ࡟ࣈࣝ࢝ࣀᘧᄇⅆࢆάⓎ࡟⥆
ࡅ࡚࠸ࡿ㸬⣙ 13 cal kBP ࡢᱜᓥ⸃ᦶࢸࣇࣛ㸦SzѸS㸭P14㸧ࡣᱜᓥⅆᒣ᭱኱ࡢࢸࣇ࡛ࣛ㸪༡஑ᕞ
୍෇࡟ศᕸࡋ㸦Fig. 1㸧
㸪ࡳ࠿ࡅࡢయ✚ࡣ 14 km3 ࡜᥎ᐃࡉࢀ࡚࠸ࡿ㸦ᑠᯘ࡯࠿㸪2013㸧㸬ࡇࡢ Sz
ѸS ᄇⅆ࠿ࡽ᪂ᮇ໭ᓅࢫࢸ࣮ࢪࡀ㛤ጞࡋࡓࡀ㸪ࡑࡢ๓࡟ࡣ 1 ୓ᖺ௨ୖࡢఇṆᮇࡀ࠶ࡿ㸦Fig. 2㸸
Okuno et al., 1997㸹ዟ㔝㸪2002㸧㸬ࡲࡓ㸪ࡇࡢఇṆᮇ࡟ࡣ㸪㧗㔝࣮࣋ࢫࢧ࣮ࢪ㸦A-Tkn㸧ࡸ᪂ᓥ
ⅆ○ὶ㸦A-Sj㸧࡞࡝ࡢጸⰋ࢝ࣝࢹࣛ㉳※ࡢࢸࣇࣛࡀᑠつᶍ࡞ࡀࡽᄇฟࡋ࡚࠸ࡿ㸬
ᱜᓥ࡜ጸⰋ࢝ࣝࢹࣛࡢ࣐ࢢ࣐⁀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 ᄇⅆ࠿ࡽ࠶ࡲࡾ㛗࠸ఇṆᮇࢆᣳࡲࡎ࡟࠾ࡇࡗ࡚࠸ࡿ㸬ࡇ
ࡢࡇ࡜ࡶ㸪୧⪅ࡢ࣐ࢢ࣐⁀ࡲࡾࡀ⊂❧࣭୪⾜ࡋ࡚άືࡋ࡚࠸ࡿࡇ࡜ࢆ♧ࡍ㸬ࡇࡢ P17 ࡢయ✚
ࡀ 1.1 km3 ࡜ SzѸS ࡟ḟࡄつᶍ࡛࠶ࡿࡇ࡜ࡶ㸪ࡑࡢࡇ࡜ࢆᙉࡃ♧၀ࡍࡿ㸬㨣⏺࢝ࣝࢹ࡛ࣛࡶ࢝
ࣝࢹࣛᙧᡂᄇⅆ࡜ᚋ࢝ࣝࢹࣛᄇⅆ࡛ྠᵝࡢ᫬㛫㛵ಀࡀ࠶ࡾ㸦ዟ㔝㸪2002㸧
㸪࢝ࣝࢹࣛⅆᒣ࡛ࡣ
୧⪅ࡀྠ᫬୪⾜ⓗ࡟㐍ࢇ࡛࠸ࡿࡢ࡛࠶ࢁ࠺㸬௨ୖࡢࡼ࠺࡟㸪 ᱜᓥⅆᒣࡢᄇⅆྐࢆ═ࡵࡿ࡜㸪
SzѸS ᄇⅆࡀᴟࡵ࡚≉ู࡛࠶ࡿࡇ࡜ࡀࢃ࠿ࡿ㸬ࡋࡓࡀࡗ࡚㸪᪂ᮇ༡ᓅࢫࢸ࣮ࢪ࡟࠶ࡿᱜᓥⅆᒣ
࡛㸪㏆࠸ᑗ᮶࡟ SzѸS ࡢࡼ࠺࡞つᶍࡢᄇⅆࡀ࠾ࡇࡿ࡜ࡣ⪃࠼㞴࠸㸬ࡑࢀࡼࡾࡶࡴࡋࢁ㸪ጸⰋ࢝
ࣝࢹࣛࡣ 16 cal kBP ࡢ A-Sj ௨㝆㸪᫂☜࡞ᄇⅆάືࡀㄆࡵࡽࢀࡎ㸪⌧ᅾࡲ࡛࡟࡝ࡢ⛬ᗘࡢ࣐ࢢ
࣐ࢆ⵳✚ࡋ࡚ࡁࡓ࠿ࢆヲࡋࡃぢ✚ࡶࡿᚲせࡀ࠶ࢁ࠺㸬ࡇࡢぢ✚ࡶࡾࡀ᫂☜࡟࡞ࢀࡤ㸪ጸⰋ࢝
ࣝࢹࣛࡢḟࡢ࢝ࣝࢹࣛᄇⅆࡢつᶍࡀ᥎ᐃ࡛ࡁࡿ㸬
- 43 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 3-08 ᆅ⊹ࡸ Ἠᆅᇦ࡟ㄆࡵࡽࢀࡿ㧗 㓟ᛶࡢⅆᒣᛶὶయࡢྡṧࡾ
⏣ཱྀᖾὒ㸦⚟ᒸ኱࣭⌮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⇕ᆅᖏ࡟ࡣᄇẼᖏࡸ Ἠ࡞࡝ࡢᆅ⇕ᚩೃࡀศᕸࡋ࡚࠸ࡿ㸬ࡇࡢࡼ
࠺࡞ᆅ⇕ᚩೃᆅࡢ࡞࠿࡟ࡣ㸪࠿ࡘ࡚㧗 ࡢⅆᒣᛶὶయࡀస⏝ࡋࡓྡṧࡾࡀㄆࡵࡽࢀࡿ㸬ࡇࡢ
ࡼ࠺࡞㊧ࡣ㸪ⅆᒣᛶὶయࡀ࣐ࢢ࣐࠿ࡽⓎ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῝ࡵࡿࡤ࠿ࡾ࡛࡞ࡃ㸪㜵⅏ୖࡶ㔜せ࡞᝟ሗࢆ୚
࠼࡚ࡃࢀࡿྍ⬟ᛶࡀ࠶ࡿ㸬
ࡇࡇ࡛ࡣ஑㔜ࡢⅆᒣάື࡟క࠺ᆅ⇕⣔ࡢⓎ㐩㐣⛬࡟ࡘ࠸࡚㸪୺࡟ඵ୎ཎⓎᆅ⇕ᖏࢆྲྀࡾୖ
ࡆ㸪ඵ୎ཎࡢᆅ⇕ᚩೃᆅࡣ࠿ࡘ࡚ⅆᒣᛶὶయࡢ㏻㊰࡛࠶ࡗࡓࡇ࡜ࢆ⤂௓ࡍࡿ㸦Fig. 1㸧
㸬
ඵ୎ཎᆅ⇕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ࡉࢀࡓ⵨Ẽ㸪
◲໬Ỉ⣲㸪஧㓟໬Ⅳ⣲➼ࡀᆅୗὸᡤ࡟ୖ᪼ࡋ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࿘㎶㒊࡛ࡣࡇࢀ࡟࢝࢜ࣜࢼ࢖ࢺࢆకࡗ࡚
࠸ࡿ㸬ࡋ࠿ࡋ࡞ࡀࡽ㸪ᑠᯇᆅ⊹࡛ࡣࡇࡢ୰࡟㸪▼ⱥ࠿ࡽ࡞ࡿ⌛໬ᒾࡀᆅ⾲࡛ㄆࡵࡽࢀ㸪⌧ᅾ
ࡢᄇẼάືୗ࡛ᙧᡂࡉࢀࡓࡶࡢ࡛࡞࠸ࡇ࡜㸪ࡍ࡞ࢃࡕ pH<2 ࡢ Cl-SO4 ᆺࡢⅆᒣᛶὶయࡀ࠿ࡘ
࡚స⏝ࡋࡓࡇ࡜ࢆ♧၀ࡋ࡚࠸ࡿ㸬ࡲࡓ㸪᫂♠▼ࡢ◲㯤ྠ఩యẚࡣ㸪⌧ᅾࡢᄇẼάືୗ㸦⵨Ẽ
ຍ⇕Ỉࡢస⏝㸧࡛࡛ࡁࡓࡇ࡜ࢆ♧ࡋ࡚࠸ࡿࡀ㸪୰࡟ࡣࡼࡾ㧗 㓟ᛶୗࡢ᮲௳ୗ࡛ᙧᡂࡋࡓࡶ
ࡢ࡛࠶ࡿࡇ࡜ࢆ♧ࡍࡶࡢࡶㄆࡵࡽࢀࡿ㸬
ࡇࡢ௜㏆ࡢᆅୗࡢ⇕Ỉኚ㉁ࡣ㸪᫂ࡤࢇ▼ࡀᆅୗ⣙ 350m ࡲ࡛ཌࡃⓎ㐩ࡋ㸪ࡑࡢୗ఩ࡣ࢝࢜
ࣜࢼ࢖ࢺࡸࣃ࢖ࣟࣇ࢕ࣛ࢖ࢺࡀᆅୗ 1000m ௨ୖࡢ῝ࡉࡲ࡛ศᕸࡋ࡚࠸ࡿ㸬ᆅୗ 100㹫ࡲ࡛ࡢ
᫂ࡤࢇ▼ࡢ◲㯤ࡢྠ఩యẚࡣ 0.5͙⛬ᗘ࡛㸪⌧ᅾࡢᄇẼάືࡢᙳ㡪ୗ࡛⏕ᡂࡋࡓࡇ࡜ࢆࡋࡵࡋ
࡚࠸ࡿ㸬ࡋ࠿ࡋ㸪ࡑࢀ௨῝ࡣ 10 ᩘ͙㹼23͙࡜㧗࠸್ࢆ♧ࡋ㸪ᆅ⾲௜㏆ࡢᄇẼάື࡜ࡣ㛵ಀࡢ
࡞࠸ࡇ࡜ࢆ㸪ࡲࡓࡇࡢࡼ࠺࡞᫂♠▼ࡢࢥ࢔࡟ࡣ APS 㖔≀ࡀㄆࡵࡽࢀ㸪ⅆᒣάື୰ᚰ㒊ࡢ㧗◲
໬⣔ࡢ⎔ቃୗ࡛ᙧᡂࡋࡓࡇ࡜ࢆ♧ࡋ࡚࠸ࡿ㸬ࡲࡓ㸪᫂ࡤࢇ▼ᖏࡢୗ఩ࡢ࢝࢜ࣜࣥ-ࣃ࢖ࣟࣇ࢕
- 45 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࣛ࢖ࢺᖏ࡟ࡣ㸪ࢺࣃ࣮ࢬ㸪ࢬࢽ▼㸪⣚ᰕ▼㸪ࢲ࢖࢔ࢫ࣏࢔࡞࡝㧗 㓟ᛶ㸪ࡍ࡞ࢃࡕⅆᒣᛶὶ
యࡢ㏻㊰௜㏆࡛ᙧᡂࡉࢀࡓ㖔≀ࡶศᕸࡋ࡚࠸ࡿ㸬ࡇࢀࡽࡢࡇ࡜࠿ࡽ㸪ᑠᯇᆅ⊹௜㏆ࡣ㸪࠿ࡘ
࡚ࡢ㧗 ࣭㓟ᛶࡢⅆᒣᛶὶయࡢ㏻㊰࡟࠶ࡓࡾ㸪ཌࡃⓎ㐩ࡍࡿ㓟ᛶኚ㉁ᖏࡣࡇࡢάື࡟ࡼࡾ⏕
ᡂࡋࡓࡶࡢ࡛࠶ࡿࡇ࡜ࡀ᫂ࡽ࠿࡛࠶ࡿ㸬࡞࠾㸪ඵ୎ཎ໭㒊࡟ࡣ⌧ᅾࡶ㓟ᛶࡢ㧗 ⇕ỈࡀᏑᅾ
ࡋ࡚࠾ࡾ㸪⌧ᅾࡶⅆᒣᛶὶయࡢάືࡀ⥆࠸࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿ㸬
ඵ୎ཎࡢ໭ 2km ࡟఩⨨ࡍࡿ኱ᓅ࡛ࡣ㸪᫂ࡤࢇ▼ᖏࡢ◲㯤ྠ఩యẚࡣⅆᒣᛶὶయࡢᏑᅾୗ࡛
ᙧᡂࡉࢀࡓࡇ࡜ࢆ♧ࡋ࡚࠸ࡿࡀ㸪⌧ᅾ࡛ࡣᆅୗ࡟㛵㐃ࡋࡓ㓟ᛶࡢ⇕Ỉࢆぢฟࡍࡇ࡜ࡀ࡛ࡁ࡞
࠸㸬኱ᓅ㸫ඵ୎ཎᆅ⇕ᖏ࡛ㄆࡵࡽࢀࡿࡼ࠺࡞ⅆᒣᛶὶయࡀస⏝ࡋࡓ⑞㊧ࡣ㸪஑㔜ⅆᒣࡢ࿘㎶
ࡢ Ἠᆅ࡟ࡢ࡯࠿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ࣆࢼࢶ࣎ⅆᒣ࡟ࡶⅆᒣᛶὶయࡢᚩೃᆅࡣᏑᅾࡋ࡚࠸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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 3-09 ⅆᒣάືึᮇࡢࢸࣇࣛࢆ౑ࡗࡓᒾ▼Ꮫⓗࣔࢽࢱࣜࣥࢢ
ʊࢭࣥࢺ࣊ࣞࣥࢬⅆᒣ 1980 ࡢ౛࣮
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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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ࢩࢼࣈࣥⅆᒣ࡜ࢣ࣮ࣝࢺⅆᒣࡢᄇⅆ
୰⏣⠇ஓ(ᮾி኱)࣭ྜྷᮏ඘ᏹ(ᐩኈⅆᒣ◊)࣭๓㔝 ῝(ᮾி኱)࣭஭ཱྀṇே(ி㒔኱)࣭
A. ࢨ࢚ࢾࢹ࢕ࣥ (࢖ࣥࢻࢿࢩ࢔ⅆᒣᆅ㉁⅏ᐖ㍍ῶࢭࣥࢱ࣮)࣭
M. ࣊ࣥࢻࣛࢫࢺ (࢖ࣥࢻࢿࢩ࢔ⅆᒣᆅ㉁⅏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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 2014 ᖺ࡟࢖ࣥࢻࢿࢩ࢔࡛ࡣࢩࢼࣈࣥⅆᒣ࡜ࢣ࣮ࣝࢺⅆᒣ࡜࡛␗࡞ࡿࢱ࢖ࣉࡢᄇⅆࡀ㉳ࡁࡓࠋ
ᆅ⌫≀⌮Ꮫⓗ࠾ࡼࡧᆅ㉁Ꮫⓗほ ࡜ᒾ▼Ꮫⓗ◊✲࠿ࡽ㸪ࡇࢀࡽ 2 ⅆᒣࡀఝࡓᆅ㉁Ꮫⓗ⫼ᬒ࡛
࡝࠺ࡋ࡚␗࡞ࡿࢱ࢖ࣉࡢᄇⅆࢆࡍࡿࡢ࠿࡜࠸࠺ᇶᮏⓗ࡞␲ၥࢆᢞࡆࡘࡅࡓࠋ
໭ࢫ࣐ࢺࣛ࡟࠶ࡿࢩࢼࣈࣥⅆᒣ࡛ࡣ 9 ୡ⣖࠿ࡽ 10 ୡ⣖ࡢⅆ○ὶᄇⅆࡀ᭱ࡶ᪂ࡋ࠿ࡗࡓࡀ㸪
2010 ᖺ 8㸪9 ᭶࡟᭷ྐึࡵ࡚ࡢᄇⅆ㸦Ỉ⵨Ẽ⇿Ⓨ㸧ࢆ㉳ࡇࡋࡓࠋ2013 ᖺ㸷᭶୰᪪࡟Ỉ⵨Ẽ⇿
Ⓨࡀ෌㛤ࡋ㸪࣐ࢢ࣐Ỉ⵨Ẽ⇿Ⓨࢆ⧞ࡾ㏉ࡋ㸪12 ᭶࡟ᒣ㡬㒊ࡢ⭾ᙇࢆకࡗ࡚⁐ᒾࡀᒣ㡬ⅆཱྀ࡟
ฟ⌧ࡋࡓࠋ12 ᭶ᮎ࠿ࡽ⁐ᒾᔂⴠ࡟క࠺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⣖ᄇⅆ࡜࡯ࡰྠࡌ࡛࠶ࡿࠋ⁐ᒾࡣᩬᬗ࡟ᐩࡴゅ㛝▼㍤▼Ᏻ
ᒣᒾ㸦SiO2 57-58%㸧࡛࠶ࡿࠋᆅ㉁Ꮫⓗ࡞◊✲࡛ࡣࡇࡢⅆᒣࡢᡂ㛗ྐࢆ㏻ࡋ࡚⇿Ⓨⓗ࡞ᄇⅆࡀ
㉳ࡁ࡚࠸࡞࠸ࡇ࡜ࢆ♧ࡋ࡚࠸ࡿࠋ
ᮾࢪࣕ࣡࡟࠶ࡿࢣ࣮ࣝࢺⅆᒣࡣ⣙ 20 ᖺ࠾ࡁ࡟ࣉࣜࢽ࣮ᘧࡢᄇⅆ㸦VEI 4㸧ࢆ⧞ࡾ㏉ࡋ࡚࠸
ࡿࠋ2014 ᖺ 2 ᭶ 13 ᪥ࡢኪ࡟ࣉࣜࢽ࣮ᘧᄇⅆࢆ㛤ጞࡋ㸪⣙ 6 ᫬㛫ᚋ࡟ᄇⅆࡣ཰ࡲࡗࡓࠋᄇ↮
ࡣୖ✵ 18-25km ࡟㐩ࡋ㸪ⅆᒣ⅊ࡣⅆᒣࡢすഃ㐲᪉ࡲ࡛ᗈࡃሁ✚ࡋࡓࠋᄇⅆࡢ๓ 2 㐌㛫๓࠿ࡽ
ᛴ⃭࡟ᆅ㟈ࡀከⓎࡋ㸪ࡑࡢ㢖ᗘ࡜ᙉᗘࢆ᫬㛫࡜࡜ࡶ࡟ቑࡋ࡚ᄇⅆࡋࡓࠋ2007-8 ᖺ࡟ࡣ㸪ⅆཱྀ
ෆ࡟⁐ᒾࢻ࣮࣒㸦⣙ 0.04 km3㸧ࡀᙧᡂࡉࢀࡓࡀ㸪ࡇࡢ⁐ᒾࢻ࣮࣒ࡣ௒ᅇࡢᄇⅆ࡛᏶඲࡟྿ࡁ
㣕ࡤࡉࢀࡓ㸦ᅗ 2㸧ࠋ௒ᅇࡢᄇⅆࡢᄇฟ㔞ࡣ 0.2-0.3 km3 ࡛࠶ࡿࠋᄇⅆࡋࡓ㍍▼ࡣ⤖ᬗ࡟ᐩࡴ㍤
▼Ᏻᒣᒾ㸦SiO2 55~56%㸧࡛࠶ࡿࠋᒾ▼Ꮫⓗ≉ᚩࡣ 2007-2008 ᖺ⁐ᒾ࡜㓞ఝࡋ࡚࠸ࡿࠋ
2013~2014 ᖺ࡟ࢩࢼࣈࣥⅆᒣ࡜ࢣ࣮ࣝࢺⅆᒣ࡛㉳ࡁࡓᄇⅆࡣ㸪㠀⇿Ⓨⓗᄇⅆ࡜⇿Ⓨⓗᄇⅆ
ࡢዲ౛࡛࠶ࡿࠋᄇⅆࡢつᶍࡣ࣮࢜ࢲ࣮࡛ࡣྠࡌ࡛࠶ࡾ㸪࣐ࢢ࣐⤌ᡂࡶ኱ࡁࡃ㐪ࢃ࡞࠸ࠋ࣐ࢢ
࣐ࡢ⵳✚῝ᗘࡸ᥎ᐃࡉࢀࡿỈࡢ㔞ࡶⰋࡃఝ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋࡋ࠿ࡋ㸪ᄇฟ⋡ࡣ୧⪅࡛኱
ࡁࡃ␗࡞ࡾ㸪ࢩࢼࣈࣥⅆᒣ࡛ 5m3/s ࡛࠶ࡿࡢ࡟ᑐࡋࢣ࣮ࣝࢺⅆᒣ࡛ࡣ 2~3 ୓ m3/s ࡛࠶ࡿ㸦ᅗ
3㸧ࠋ୍᪉࡛㸪ࢣ࣮ࣝࢺⅆᒣ࡛ࡣࡇࡢ㸴ᖺ㛫࡟⤌ᡂࡀྠࡌ࣐ࢢ࣐ࡀ⁐ᒾࢻ࣮࣒ᄇⅆ࡜ࣉࣜࢽ࣮
ᘧᄇⅆࢆ㉳ࡋ࡚࠸ࡿࠋࢩࢼࣈࣥⅆᒣ࡜ࢣ࣮ࣝࢺⅆᒣ㸪࠶ࡿ࠸ࡣࢣ࣮ࣝࢺⅆᒣࡔࡅ࡛ࡶ㸪␗࡞
ࡿࢱ࢖ࣉࡢᄇⅆࡀ␗࡞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㸦ྑࠋ࢖ࣥࢻࢿࢩ࢔ⅆᒣᆅ㉁⅏ᐖ㍍ῶࢭࣥࢱ࣮ᥦ౪㸧
- 49 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 4-02 ࢖ࣥࢻࢿࢩ࢔ࡢⅆᒣᆅᙧ
Ᏺᒇ௨ᬛ㞝㸦㔠ἑ኱࣭ྡ㄃ᩍᤵ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 ࡟ཬࡪ࢖ࣥࢻࢿࢩ࢔኱ࢫࣥࢲᘼ࡟ἢ࠺ⅆᒣࡢᴫせࢆ㸪ᆅᙧᅗ࣭Google Earth 3D ⏬ീࡢุ
ㄞ࠿ࡽ᫂ࡽ࠿࡟ࡋ㸪Ᏺᒇ㸦1979, 1983, 2012㸧࡟ࡋࡓࡀࡗ࡚ศ㢮ࡋࡓ㸬ࡋࡓࡀࡗ࡚ᮏሗ࿌ࡣᆅ
ᙧ᝟ሗ᥇ྲྀࢆ୺య࡜ࡍࡿணᐹసᴗ⤖ᯝࡢሗ࿌࡜ࡶ࠸࠼ࡿෆᐜ࡛࠶ࡿࡀ㸪ከࡃࡢ᪂ࡓ࡞᝟ሗࡀ
ᚓࡽࢀࡓࡢ࡛㸪ࡇࡇ࡟ሗ࿌ࡍࡿ㸬௒ᚋࡉࡽ࡟ᆅ㉁࣭ᒾ▼࣭ᖺ௦್࡞࡝ࡢ᝟ሗࢆຍ࠼㸪ࡼࡾ᏶
඲࡞ᡂᯝࢆᑟࡁࡓ࠸㸬
࢖ࣥࢻࢿࢩ࢔࣭኱ࢫࣥࢲิᓥࡢⅆᒣ⥲ᩘ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㉁ࢫࢥࣜ࢔ୣ࣭ᑠᴙ≧ⅆᒣ࣭࣐࣮ࣝ 22 ಶ㸧ࡢෆヂ࡜࡞ࡗ࡚࠸ࡿ㸬ࡓࡔࡋᚋ
࢝ࣝࢹࣛⅆᒣࡣ࢝ࣝࢹࣛⅆᒣ࡟ྵࡵᩘ࠼࡚࠸࡞࠸㸬すኴᖹὒỿࡳ㎸ࡳᖏࡢⅆᒣ⥲ᩘ 940 ಶࡢ
࠺ࡕᡂᒙⅆᒣࡀ 676 ಶ 72 %࡛࠶ࡿࡢ࡟ᑐࡋ㸪኱ࢫࣥࢲิᓥࡢᡂᒙⅆᒣࡢ༨ࡵࡿ๭ྜࡣ 76 %
࡜ࡸࡸ㧗࠸㸬ࡋ࠿ࡋᓥᘼ࡟ࡣࡵࡗࡓ࡟ฟ⌧ࡋ࡞࠸⋞Ṋᒾ㉁࣐ࢢ࣐㉳※ࡢ⁐ᒾཎࡀ 2 ಶࡶᏑᅾ
ࡍࡿࡇ࡜㸪⋞Ṋᒾ㉁࣐ࢢ࣐㉳※ࡢࢫࢥࣜ࢔ୣ࡞࡝ࡢ༢ᡂⅆᒣ⩌ࡀ㸪すኴᖹὒࡢᖹᆒ 9 %࡟ᑐ
ࡋ࡚ 14 %࡜㧗࠸ฟ⌧⋡ࢆ♧ࡍࡇ࡜ࡣὀ┠ࡉࢀࡿ㸬࢝ࣝࢹࣛⅆᒣࡢ 8 %ࡣすኴᖹὒࡢᖹᆒ 7 %
࡜ࡃࡽ࡭ᕪࡀ࡞࠸㸬ᡂᒙⅆᒣࡢⓎ㐩ࡣ Java ᓥࡢᡂᒙⅆᒣࡢࡳึᮇࡢࡶࡢࡀᑡ࡞ࡃ㸪Sumatra,
Flores ᓥ࡞࡝ࡢᡂᒙⅆᒣ࡛ࡣⓎ㐩ึᮇࡢᐩኈᒣᆺࡢࡶࡢࡀከ࠸㸬ᓥᘼࡈ࡜࡟ⅆᒣᙧᡂ࡟㐜㏿
ࡀ࠶ࡗࡓࡢ࠿㸪Ⓨ㐩㏿ᗘ࡟ᕪࡀ࠶ࡗࡓࡢ࠿⯆࿡῝࠸㸬
Sumatra ᓥ࡜ Java ᓥ࡛ࡣỿࡳ㎸ࡴࣉ࣮ࣞࢺࡢ᪉ྥ࡟ᕪ࠿ࡽ࠿㸪Sumatra ᓥ࡛ࡣⅆᒣࡀྑᶓࡎ
ࢀ᩿ᒙ࡟ἢࡗ࡚ 50 km ࡈ࡜࡟࡯ࡰ㸯ิ࡟ᓥᘼఙ㛗᪉ྥ࡟୪ࡪࡢ࡟ᑐࡋ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㓄ิࢆࡍࡿ౛ࡣᮾ໭᪥ᮏᘼ(Tamura et al., 2002)
࡜୰⡿ Costa Rica㸦Ᏺᒇ㸪1999㸧࡟ぢࡽࢀࡿࡔࡅ࡛࠶ࡿ㸬
ᆅᙧᅗุㄞ࠿ࡽ Sumatra ᓥࡢⅆᒣࡢ୍㒊㸪Java ᓥࡢ኱㒊ศࡢⅆᒣࡢᆅᙧศ㢮ᅗࡀసᡂࡉࢀ
ࡓ㸬ࡑࡢ୍㒊ࢆᥦ♧ࡍࡿ࡜࡜ࡶ࡟㸪ࡑࢀ࠿ࡽㄞࡳྲྀࢀࡿ஦౛࡟ࡘ࠸࡚ゎㄝࡍࡿ㸬
- 51 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 5-02 ࣇ࢕ࣜࣆࣥࡢࣆࢼࢶ࣎ⅆᒣᒣ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.)
ࣇ࢕ࣜࣆࣥඹ࿴ᅜࣝࢯࣥᓥ୰㒊࡟࠶ࡿࣆࢼࢶ࣎ⅆᒣࡣ 1991 ᖺ࡟኱ᄇⅆࢆ㉳ࡇࡋ㸪ᒣ㡬㒊࡟
࢝ࣝࢹࣛ†ࢆ⏕ࡌ࡚࠸ࡿ㸬ࡇࡢ࢝ࣝࢹࣛ࿘㎶࡟ࡣ㸪᭱᪂ᮇࡢᄇⅆάື࡟ࡼࡿࢻ࣮࣒⁐ᒾࡸⅆ
○ὶࡀศᕸࡋ࡚࠾ࡾ㸪άືྐࡢ᚟ඖ࡟㔜せ࡛࠶ࡿ㸬᪂ᮇࡢⅆᒣάືࡣᒣ㯄ࡢⅆ○ሁ✚≀ࡢ㸯㸲
C ᖺ௦ ᐃ࠿ࡽ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ࡢᒾయ࡟ࡘ࠸࡚ࡶ⇕࣑ࣝࢿࢵࢭ
ࣥࢫ㸦TL㸧ἲ࡟ࡼࡾ┤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☜ᐃࡍࡿࡓࡵ࡟ࡣ㸪ᆅ
㉁᫬௦࡟ཷࡅࡓᨺᑕ⥺㔞㸦ࣃࣞ࢜ࢻ࣮ࢫ㸪PD㸧࡜㸯ᖺ㛫࡟ヨᩱࡀཷࡅࡿ⥺㔞㸦ᖺ㛫⥺㔞㸪AD㸧
ࡢ཮᪉ࡢ ᐃࡀᚲせ࡛࠶ࡿ㸬ᚋ⪅࡟ࡘ࠸࡚ࡣ㸪ᨺᑕ
ᛶඖ⣲࡛࠶ࡿ U㸪Th㸪K㸦K2O㸧ࡢ඲ᒾ ᐃ࠿ࡽồࡵ
ࡿࡇ࡜ࡀ࡛ࡁ㸪Ȗ ⥺ࢫ࣌ࢡࢺ࣓ࣟࢺ࣮ࣜἲ࡟ࡼࡾࡍ
࡛࡟⟬ᐃࡉࢀ࡚࠸ࡿ㸬୍᪉ࠊPD ࡟ࡘ࠸࡚ࡣ㸪ேᕤⓗ
࡞ᨺᑕ⥺↷ᑕ㸦Ȗ ⥺㸧࡟ࡼࡾồࡵࡿࡇ࡜ࡀᚲせ࡛࠶
ࡾ㸪ṇ☜࡞ホ౯࡟ࡣ」ᩘ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⢭ᗘࡣ඲ࡃຎࡗ࡚࠸ࡿ㸬௒ᚋ㸪Ȗ ⥺↷
ᑕࢆቑࡸࡋ࡚ ᐃࡍࡿࡇ࡜࡛⢭ᗘࡢ㧗࠸ᖺ௦ࡀồࡵ
- 58 -
Fig. 1 Location of TL samples.
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡽࢀࡿ㸬࡞࠾㸪ᖺ௦࡜ࡣ┤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㏻ᖖ࡜ࡣ␗࡞
ࡿ࣐ࢢ࣐ศ໬ࡀ᝿ᐃࡉࢀ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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲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⪅ࡽࡣⅆཱྀෆ࡟ᔂⴠࡋࡓ
ࣈࣟࢵࢡ୰ࡢᮦ໬▼㸦Fig. 1㸧ࡢᨺᑕᛶⅣ⣲㸦14C㸧ᖺ௦ࢆ ᐃࡋࡓࡢ࡛㸪ࡇࡢ⤖ᯝࢆሗ࿌ࡍࡿ㸬
14
C ⃰ᗘ ᐃࡣ㸪ྡྂᒇ኱Ꮫࡢຍ㏿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
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⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡑࡢᚋ㸪ⅆཱྀෆቨ࡟㟢ฟࡍࡿ†ᡂᒙࢆほᐹࡋࡓ⤖ᯝ㸪ᮦ໬▼ࡀ⏘ࡍࡿᒙ‽ࡣࡦ࡜ࡘࡋ࠿☜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ࡇࡢ᫬ᮇࡢᄇⅆ࡛⌧ᅾࡢ
ࡼ࠺࡟ⅆཱྀ†ࡀ࠶ࡿᮇ㛫Ꮡᅾࡋ࡚࠸ࡓࡇ࡜ࢆ♧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 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 5-04 ࣃ࢖ࢱࣥ†ࡢ࣮࣎ࣜࣥࢢ᥀๐(㏿ሗ)
㫽஭┿அ(⇃ᮏ኱)࣭E. Bariso࣭D.J. Rivera࣭R. Lim࣭C. Pogay࣭A. Daag (PHIVOLCS)࣭
ᒣᓮᆂ஧࣭୰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.)
᪥ᮏྠᵝ࡟ᩘከࡃࡢάⅆᒣࢆ᭷ࡍࡿࣇ࢕ࣜࣆࣥඹ࿴ᅜ࡛ࡣ㸪ᚎࠎ࡟࡛ࡣ࠶ࡿࡀྛⅆᒣࡈ࡜࡟
ᄇⅆྐ◊✲ࡀ࠾ࡇ࡞ࢃࢀࡘࡘ࠶ࡿ㸬ࡋ࠿ࡋ㸪ᒙᗎࡢᇶ‽࡜࡞ࡿᗈᇦࢸࣇࣛࡢᏑᅾࡀㄆ㆑ࡉࢀ
࡚࠸࡞࠿ࡗࡓࡇ࡜࠿ࡽ㸪ṇ☜࡞ᒙ఩㛵ಀ࡟ᇶ࡙ࡃⅆᒣάືࡢᢕᥱࡀᅔ㞴࡛࠶ࡗࡓ㸬㏆ᖺ㸪ࣝ
ࢯࣥᓥ༡ᮾ➃࡟࢖ࣟࢩࣥ㸦Irosin㸧࢝ࣝࢹࣛࢆᙧᡂࡋࡓ኱つᶍⅆ○ὶᄇⅆ(41 cal kBP)࡟࠾࠸࡚㸪
㝆ୗⅆᒣ⅊㸦co-ignimbrite ash-falls㸧ࡢᏑᅾࡀ᫂ࡽ࠿࡟ࡉࢀ㸪ࣇ࢕ࣜࣆࣥ࡟࠾ࡅࡿᗈᇦᑐẚࡢ
㘽ᒙ࡜࡞ࡾᚓࡿྍ⬟ᛶࡀ♧ࡉࢀࡓ( Mirabueno et al., 2011)㸬ࡇࡢࡼ࠺࡞㘽ᒙ࡜࡞ࡾᚓࡿࢸࣇࣛ
ࡢ࢝ࢱࣟࢢ໬ࡣࡇࡢᆅᇦࡢⅆᒣᏛ࡟኱ࡁࡃᐤ୚ࡍࡿࡇ࡜࠿ࡽ㸪࢖ࣟࢩࣥᄇⅆ௨㝆ࡢ㧗⢭ᗘࢸ
ࣇࣛ࢝ࢱࣟࢢࡢᵓ⠏ࢆᙜ㠃ࡢ┠ᶆ࡜ࡋ࢖ࣟࢩࣥ࢝ࣝࢹࣛ࿘㎶ࡢ㸱ࢧ࢖ࢺ࡛࣮࣎ࣜࣥࢢㄪᰝࢆ
࠾ࡇ࡞ࡗ࡚ࡁࡓ㸬ࡋ࠿ࡋ㸪ࢸࣇࣛಖᏑᛶࡢࡼ࠸†ᡂᒙࡢᏑᅾࢆᮇᚅࡋࡓ࢝ࣝࢹࣛෆࡢ࣮࣎ࣜ
ࣥࢢㄪᰝ࡛ࡣ㸪⤖ᯝ࡜ࡋ࡚Ἑᕝᡂࡢሁ✚≀࡜ࣈࣝࢧࣥⅆᒣ㉳※ࡢࣛࣁ࣮ࣝሁ✚≀ࢆ୺య࡜ࡋ
࡚࠾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ࡑࡇ࡛௒ᅇࡣ᥀๐ㄪᰝࡢᑐ㇟
ࢆ㟼࠿࡞ሁ✚⎔ቃࡀ᥎ᐃࡉࢀࡿࣃ࢖ࢱࣥ†ࡢ†ᡂᒙ࡟ࢱ࣮ࢤࢵࢺࢆኚ᭦ࡋ 2015 ᖺ 1 ᭶ᮎࡼ
ࡾ᥀๐ࢆ㛤ጞࡋࡓ㸬ࣃ࢖ࢱࣥ†ࡣ෇ᙧࢡ࣮ࣞࢱ࣮≧ࡢᆅᙧ࡜࣒ࣜࢆᙧᡂࡍࡿࢧ࣮ࢪሁ✚≀ࡢ
Ꮡᅾ࠿ࡽࢱࣇࣜࣥࢢ࡜᥎ᐃࡉࢀࡿ㸬⌧ᅾ㸪ࢱࣇࣜࣥࢢ୰ᚰ௜㏆ࡢࡳࡀ‣Ỉࡋ࡚࠾ࡾ㸪࣒ࣜෆ
ഃᩳ㠃࡟ࡣỈ⏣ࡀᙧᡂࡉࢀ࡚࠸ࡿ㸬†࡟ࡣ໭ഃ࡟ᖜᩘ m ࡢᑠᕝࡀ࠶ࡿࡢࡳ࡛஦ᐇୖ†࡟ὶධ
ࡍࡿἙᕝࡣ࡞࠸ࡇ࡜࠿ࡽ㸪ὥỈ࡟ࡼࡿሁ✚≀ࡢኚ໬ࡣẚ㍑ⓗ㍍ᚤ࡞ࡶࡢ࡜ᛮࢃࢀࡿ㸬ᐇ㝿㸪
᳜≀⌛㓟యศᯒࢆ┠ⓗ࡜ࡋࡓྜྷ⏣࡯࠿(2011)࡛ࡣ㸪ᡭືᘧࣆࢫࢺ࣭ࣥ ࢧࣥࣉ࣮ࣛࢆ⏝࠸ 240cm
ࡢヨᩱ᥇ྲྀࢆ࠾ࡇ࡞࠸㸪඲ᒙ‽ࡀࢩࣝࢺ࡛࠶ࡿࡇ࡜ࢆ♧ࡋ࡚࠾ࡾ㸪᭱ୗ㒊௜㏆ࡢᖺ௦ࡀࡼࡑ
2,500 ᖺ๓࡛࠶ࡿࡇ࡜ࡶሗ࿌ࡋ࡚࠸ࡿ㸬Fujiki et al.(2013)࡛ࡣⰼ⢊᥇ྲྀࡢࡓࡵ࡟⾜ࡗࡓࣁࣥࢻ
࣮࣮࢜࢞࡟ࡼࡿ᥇ྲྀ࡛⣙ 300cm ࡢヨᩱࢆᚓ࡚࠾ࡾ㸪ྠᵝ࡟඲ᒙ‽ࡀࢩࣝࢺ࡛࠶ࡿࡇ࡜㸪῝ᗘ
278cm ࡛⣙ 1,200 cal BP ࡛࠶ࡿࡇ࡜ࢆ♧ࡋ࡚࠸ࡿ㸬 ᥀๐ᆅⅬࡣ†ࡢ୰ᚰ࡟࡛ࡁࡿ㝈ࡾ㏆࠸ᆅ
Ⅼ࡜ࡋ࡚༡ᮾഃࢆ㑅ᐃࡋ㸪50m ࡢணᐃ࡛᥀๐ࢆ㛤ጞࡋࡓ㸬2 ᭶ 6 ᪥⌧ᅾ῝ᗘ 27m ࡲ࡛ SPT ࡟
- 62 -
⚟ᒸ኱Ꮫᅜ㝿ⅆᒣᄇⅆྐ᝟ሗ◊✲ᡤ
ㅜ എ◊✲㞟఍࡞ࡽࡧ࡟ ➨ ᅇす᪥ᮏⅆᒣάື◊✲㞟఍
ㅮ₇せ᪨㞟 ࡼࡾ᥀๐ࡀ㐍⾜ࡋ࡚࠸ࡿ㸬᥇ྲྀࡉࢀࡓࢥ࢔ࡣඛ⾜◊✲ྠᵝ࡟኱㒊ศࡀࢩࣝࢺ࠿ࡽ࡞ࡾ㸪ᬯ⅊
Ⰽ࠿ࡽ㯮Ⰽࢆ࿊ࡋ㸪ࡲࡓ᪤࡟」ᩘᒙ‽࡛ࢸࣇࣛᒙࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸬ᮏㅮ₇࡛ࡣ᥀๐ࡢ≧ἣ
ࢆ⤂௓ࡍࡿ㸬
Fig.1 ఩⨨ᅗ
Fig.2 ࣃ࢖ࢱࣥ†࡜᥀๐ࢧ࢖ࢺ఩⨨ (google map ࡟ࡼࡿ)
- 63 -
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