Field Trip after International Joint Workshop
on Slow-to-Fast Earthquakes 2022
Updated on August 23
Post-meeting Field Trip (17–18 September 2022)
Median Tectonic Line and high-pressure metamorphic rocks in subduction zones: Matsusaka and Ise, Mie Prefecture
A two-day geological field trip will be conducted after the plenary session. In Matsusaka, we will observe outcrops of the Median Tectonic Line (MTL), which is thought to record a multi-stage faulting history of island-arc crust from deep plastic deformation to shallow brittle deformation. In Ise, we will examine outcrops of high-pressure metamorphic rocks of the Sanbagawa Belt and tectonic mélange of the Kurosegawa Belt that formed at the subduction plate boundary, as well as seamount rocks accreted at depth. The white paving stones of the Ise Jingu Shrine are gravels of chert or quartz veins and are derived from accretionary complexes. The Izanagi plate, which subducted beneath the eastern margin of the Asian continent during the Mesozoic, is named after Izanagi, the father deity of Amaterasu, who is worshipped at the Ise Jingu Shrine.
Fig. 1 Geological map of the Nara and Ise areas, showing the locations of fieldtrip stops (yellow stars). Modified from AIST (2022) Seamless digital geological map of Japan V2.
Overview
Meet: 17 September (Sat.) 8:00 in Nara City (near Kintetsu Nara Station)
Break-up: 18 September (Sun.) after 15:00 from Kintetsu Ujiyamada Station
Stay: Hotel in Matsusaka City (all arrangements will be made by the organizer)
Number of participants: Maximum of 30 people (selection will be made after the deadline)
Participation fee: 7,000 yen (includes one-night accommodation in Matsusaka city)
Guides: Asuka Yamaguchi (AORI, UTokyo), Norio Shigematsu (AIST), Takayuki Uchino (AIST)
Remarks
We will be traveling in rental cars. Rental cars and gas will be arranged and payed by the project.
Sampling is not permitted because the MTL outcrop is classified as a natural monument.
A walk of a few hundred meters along the rocky beach will be necessary on the second day.
It takes about 1.5 hours to travel from Ujiyamada Station to Nagoya Station and about 2 hours from Ujiyamada to Osaka Namba Station (using Kintetsu limited express).
Itinerary
Day 1: Saturday, 17 September
MTL in Matsusaka
Guided by Dr. Norio Shigematsu (AIST)
Meet at 8:00 a.m. (at Kintetsu Nara Station)
Stop 1: Tsukiide outcrop of the MTL
Stop 2: Awano-Tabiki outcrop of the MTL
Stop 3: AIST groundwater observation facility
Overnight stay: Hotel in Matsuzaka (participants to arrange own dinners)
Fig. 2 3D model of MTL fault-zone architecture in the area of the Awano-Tabiki outcrop (Katori et al., 2021).
Fig. 3 Reactivation of the MTL fault zone. Four stages of fault activity are recorded at the Awano-Tabiki outcrop (Shigematsu et al., 2017).
Day 2: Sunday, 18 September
High-pressure metamorphic rocks in the Toba and Ise areas
Guided by Dr. Takayuki Uchino (AIST)
Stop 4: Pelitic schist of the Sanbagawa Belt at Arashima Beach
Stop 5: Shale-dominated mélange of the Kurosegawa Belt at Totani Beach (subject to change depending on tide level)
Stop 6: Greenstone of Asamagatake (deep part of an accreted seamount)
Break-up at around 15:00 at Kintetsu Ujiyamada Station
(Option: Visit Ise Jingu Naiku Shrine, break-up at Ujiyamada at around 17:00)
Fig. 4 Outcrop of the Sanbagawa Belt at Arashima Beach (photograph taken by A. Yamaguchi). Pelitic schists with abundant quartz veins can be observed.
Fig. 5 Ujibashi Bridge, the entrance to the Ise Jingu Naiku Shrine (photograph from www.pakutaso.com).
Related references
Day 1
Czertowicz et al. (2019) Progress in Earth and Planetary Science, https://doi.org/10.1186/s40645-019-0261-6
Katori et al. (2021) Journal of Structural Geology, https://doi.org/10.1016/j.jsg.2021.104446
Matsumoto and Shigematsu (2018) Earth, Planets and Space, https://doi.org/10.1186/s40623-017-0765-5
Mori et al. (2015) Island Arc, https://doi.org/10.1111/iar.12129
Shigematsu et al. (2012) Tectonophysics, https://doi.org/10.1016/j.tecto.2012.01.024
Shigematsu et al. (2017) Tectonophysics, https://doi.org/10.1016/j.tecto.2016.12.017
Wibberley and Shimamoto (2005) Nature, https://doi.org/10.1038/nature03901
Day 2
Uchino (2015) GSJ Chishitsu News (in Japanese), https://www.gsj.jp/data/gcn/gsj_cn_vol4.no3_69-74.pdf
Uchino et al. (2017) Geology of the Toba District, Quadrangle Series 1:50,000 (in Japanese with English abstract), https://www.gsj.jp/Map/EN/geology4-11.html#11079
Uchino (2018) GSJ Chishitsu News (in Japanese), https://www.gsj.jp/data/gcn/gsj_cn_vol7.no4_91-101.pdf
奈良全体集会・巡検 (9/17-18)
三重県松阪・伊勢の中央構造線と沈み込み帯の高圧変成岩
全体集会後に1泊2日の地質巡検を行います。松阪では、島弧地殻深部の塑性変形から浅部の脆性変形まで複数ステージの断層運動履歴を記録していると考えられる中央構造線の露頭を観察します。伊勢では、沈み込みプレート境界で形成された三波川帯の高圧変成岩と黒瀬川帯のテクトニックメランジュ、および地下深部で付加した海山の岩石を観察します。伊勢神宮の白い敷石（お白石）は付加体に由来するチャートや石英脈の礫です。また、中生代にアジア大陸東縁に沈み込んでいたイザナギプレートは、内宮の祭神である天照大御神の父神であるイザナギに由来しています。
＜概要＞
集合：9/17 (土) 8:00 奈良市内 (近鉄奈良駅近く)
解散：9/18 (日) 15:00以後 近鉄宇治山田駅
宿泊：松阪市内ホテル (一括手配)
参加人数：最大30人程度 (締め切り後に選考します)
参加費用：7,000円（松阪市での1泊ホテル代を含む）
案内者：山口飛鳥 (東京大学大気海洋研究所)、重松紀生 (産業技術総合研究所)、内野隆之 (産業技術総合研究所)
＜備考＞
・レンタカーに分乗して移動します。レンタカー、ガソリンは領域が手配および費用負担を行います。
・中央構造線露頭は天然記念物のためサンプル採取は禁止です。
・1日目は露頭まで車で行けます。2日目は海岸沿いを数百m程度歩きます。
・宇治山田駅から名古屋駅まで約1時間半、大阪なんば駅まで約2時間かかります（近鉄特急利用）。
＜行程＞
1日目 9月17日（土）：
松阪の中央構造線
案内者：重松紀生博士 (AIST)
朝8:00集合（近鉄奈良駅周辺）
・Stop 1: 中央構造線 月出露頭
・Stop 2: 中央構造線 粟野・田引露頭
・Stop 3: 産総研地下水観測施設
宿泊：松坂市内ホテル（夕食各自）
2日目 9月18日（日）:
鳥羽・伊勢周辺の高圧変成岩類
案内者：内野隆之博士 (AIST)
・Stop 4: 安楽島海岸の三波川帯泥質片岩
・Stop 5: 砥谷海岸の黒瀬川帯泥質メランジュ (潮位により変更可能性あり)
・Stop 6: 朝熊ヶ岳の御荷鉾緑色岩（プレート境界深部で付加した海山）
・15:00ごろ 近鉄宇治山田駅解散
（オプション：伊勢神宮内宮参拝→宇治山田解散17:00ごろ）
＜関連文献＞
1日目
Wibberley and Shimamoto (2005) Nature https://doi.org/10.1038/nature03901
Shigematsu et al. (2012) Tectonophysics https://doi.org/10.1016/j.tecto.2012.01.024
Mori et al. (2015) Island Arc https://doi.org/10.1111/iar.12129
Shigematsu et al. (2017) Tectonophysics https://doi.org/10.1016/j.tecto.2016.12.017
Matsumoto and Shigematsu (2018) Earth, Planets and Space https://doi.org/10.1186/s40623-017-0765-5
Czertowicz et al. (2019) Progress in Earth and Planetary Science https://doi.org/10.1186/s40645-019-0261-6
Katori et al. (2021) Journal of Structural Geology https://doi.org/10.1016/j.jsg.2021.104446
2日目
内野ほか（2017）5万分の1地質図幅「鳥羽」 https://www.gsj.jp/Map/EN/geology4-11.html#11079
内野 (2015) GSJ地質ニュース https://www.gsj.jp/data/gcn/gsj_cn_vol4.no3_69-74.pdf
内野 (2018) GSJ地質ニュース https://www.gsj.jp/data/gcn/gsj_cn_vol7.no4_91-101.pdf