著者

都司 嘉宣 佐竹 健治 石辺 岳男 楠本 聡 原田 智也 西山 昭仁 金 幸隆 上野 俊洋 室谷 智子 大木 聖子 杉本 めぐみ 泊 次郎 Heidarzadeh Mohammad 綿田 辰吾 今井 健太郎 Choi Byung Ho Yoon Sung Bum Bae Jae Seok Kim Kyeong Ok Kim Hyun Woo

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.86, no.3/4, pp.29-279, 2012-03-16

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We report the results of field surveys conducted by the Earthquake Research Institute, to measure tsunami heights from the 2011 off the Pacific coast of Tohoku, Japan Earthquake (M 9.0), on March 11. Measurements were taken at 296 points on the Sanriku coasts of Aomori, Iwate, and Miyagi Prefectures, and the Pacific coasts of Ibaraki and Chiba Prefectures. The data are included in the results of the 2011 Tohoku Earthquake Tsunami Joint Survey Group. We did not cover the Sendai plain in the southern Miyagi Prefecture because other parties extensively measure there, nor Fukushima Prefecture because of the accident of the Fukushima Dai-ichi nuclear power plant. The twelve surveys first sought traces indicating tsunami runup or inundation heights. Reliability was classified into A (most reliable based on clear physical evidence and eyewitness accounts), B (mostly based on natural traces), and C (least reliable based on equivocal evidence). Most physical evidence obtained after June was not significant; therefore, reliance was mostly placed on eyewitness accounts. Locations and relative heights above sea level were measured using handheld GPS receivers, auto-level, or total station. The measured heights were corrected for differences in tide level between measurement time and tsunami arrival time. The results are shown on table and four regional maps; however, the details of each measurement, including locations shown on 1:25,000 maps and photographs of evidence are shown in the Appendix. Along the northern Sanriku coast (Aomori and Iwate), most of the 141 heights range between 10m and 30m. Runup heights exceeding 30m were measured at one location in Noda Village and nine locations in Miyako City. On the southern Sanriku coast in Miyagi, most of the 76 measurements range between 4 and 20 m. On the Ibaraki coast, 36 measurements range from 2.8 to 8.1 m, and the heights generally decease toward the south. On the Chiba coast, 43 measurements range from 0.7 to 7.9 m, with the maximum height near Iioka, Asahi City.

著者

今井 健太郎

出版者

Japan Society of Civil Engineers

雑誌

海岸工学論文集 (ISSN:09167897)

巻号頁・発行日

vol.55, pp.291-295, 2008-10-10 (Released:2010-06-04)

参考文献数

13

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A statistical analysis by using the filed data of damage of tree in a coastal forest due to a past tsunami was carried out, and the influence factor that contributed to damage of tree due to tsunami was extracted from a statistical analysis. And then, statistical models were developed by using the filed data. The statistical model for lodging rate explains the actual measurement value well by diameter of tree, root form, dn and tsunami inundation depth, The statistical model for destruction rate explains the actual measurement value well by root form, dn and tsunami inundation depth. In addition, actual probability of occurrence of tree damage and the probability of the present model used inundation depth from tsunami simulation were compared, and suitability of the present model was examined.

著者

石橋 正信 馬場 俊孝 高橋 成実 今井 健太郎

出版者

日本自然災害学会

雑誌

自然災害科学 (ISSN:02866021)

巻号頁・発行日

vol.37, no.1, pp.125-142, 2019 (Released:2020-02-29)

参考文献数

12

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南海トラフの沈み込み帯において,M9クラス巨大地震とそれにともなう巨大津波の発生の可能性が内閣府により指摘されて久しい。この津波被害想定によると,地震域近傍の沿岸地域では地震発生から数分後に巨大な津波が到達してしまうため,津波防災に向けた行動計画の再構築や人的被害軽減のための迅速な対応策の検討が極めて重要になる。その対応策のひとつとして,高速かつ高精度な即時津波予測が有効と考えられる。本研究では,地震と津波観測に向けた稠密海底観測網(DONET)による沖合観測網を利用した即時津波予測システムを構築し,和歌山県沿岸6地域において実装を行い,その有効性の検討を行った。本システムにより,地震と津波の初動到達時間を即時評価できること,沿岸津波高や浸水域の即時予測が可能であることを示した。さらに,1944年昭和東南海地震の事例と内閣府のM9クラス巨大地震の波源シナリオを用いて本システムの予測精度を検証した。本システムで即時予測される沿岸津波高や浸水域面積はやや過大評価傾向にあるものの,おおむね安全側の予測結果となり,津波防災上有効なシステムであることを示した。

著者

今井 健太郎 都司 嘉宣 林 豊

出版者

公益社団法人 土木学会

雑誌

土木学会論文集B2(海岸工学) (ISSN:18842399)

巻号頁・発行日

vol.70, no.2, pp.I_211-I_215, 2014 (Released:2014-11-12)

参考文献数

6

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Waveform analysis using data by the 2010 Chilean tsunami obtained in Tokyo Bay were carried out. Numerical experiments using single sine wave with various periods in and around the bay were also carried out. Then we conclude that a tsunami in Tokyo Bay is characterized by a tsunami originated from the Seiche excited in Sagami Bay; the Seiche in Sagami Bay is efficiently excited from offshore tsunami whose period is 30 min or more.

著者

松本 浩幸 柄本 邦明 今井 健太郎 高橋 成実

出版者

公益社団法人 土木学会

雑誌

土木学会論文集B2(海岸工学) (ISSN:18842399)

巻号頁・発行日

vol.76, no.2, pp.I_319-I_324, 2020 (Released:2020-11-04)

参考文献数

9

被引用文献数

1

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本研究では,リアルタイム津波検知手法の高度化のために,台風接近時に観測された海底津波計データを精査して,地震にともなう津波との相違点を明らかにした.台風接近時と地震にともなう津波発生時では,観測波形の卓越周波数の特徴が異なることが判明した.すなわち,台風接近時には広帯域にエネルギーが分布するのに対し,地震にともなう津波発生時には低周波のエネルギーが卓越する.次に,微小振幅波理論にもとづくカットオフ周波数で津波を検出するリアルタイムフィルタを設計し,海底津波計の近傍で発生した地震に適用した.検出した津波は数値計算と整合し,設計フィルタの妥当性を検証した.ただし,台風接近時にはうねり成分が含まれることから,うねり成分を除去するカットオフ周波数の検討が必要であることを示唆する.

著者

冨岡 展行 高橋 智幸 今井 健太郎 越村 俊一

出版者

公益社団法人 土木学会

雑誌

海岸工学論文集 (ISSN:09167897)

巻号頁・発行日

no.52, pp.266-270, 2005

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2004年9月5日23時57分にM7.4の地震が紀伊半島南東沖で発生した. 震源は南海トラフ沿いに位置しているが, 東南海地震の想定震源域とは異なっていた. この海域で想定されているのはプレート境界型地震であり, これによる津波被害は既に調査済みであるが, 今回のような南海トラフ沿いで発生するプレート内部型の中規模地震による津波は未想定である. よって, 今後の津波防災において今回のような地震津波をどのように取扱うのか検討するため, 各研究機関から発表された断層パラメータを参考にして, 津波の数値計算を実施した. その結果, 大部分の地域でプレート境界型地震による津波の方がプレート内部型によるものより大きくなることが確認された.

著者

都司 嘉宣 佐竹 健治 石辺 岳男 楠本 聡 原田 智也 西山 昭仁 金 幸隆 上野 俊洋 室谷 智子 大木 聖子 杉本 めぐみ 泊 次郎 Heidarzadeh Mohammad 綿田 辰吾 今井 健太郎 Choi Byung Ho Yoon Sung Bum Bae Jae Seok Kim Kyeong Ok Kim Hyun Woo

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.86, no.3-4, pp.29-279, 2012-03-16

---

We report the results of field surveys conducted by the Earthquake Research Institute, to measure tsunami heights from the 2011 off the Pacific coast of Tohoku, Japan Earthquake (M 9.0), on March 11. Measurements were taken at 296 points on the Sanriku coasts of Aomori, Iwate, and Miyagi Prefectures, and the Pacific coasts of Ibaraki and Chiba Prefectures. The data are included in the results of the 2011 Tohoku Earthquake Tsunami Joint Survey Group. We did not cover the Sendai plain in the southern Miyagi Prefecture because other parties extensively measure there, nor Fukushima Prefecture because of the accident of the Fukushima Dai-ichi nuclear power plant. The twelve surveys first sought traces indicating tsunami runup or inundation heights. Reliability was classified into A (most reliable based on clear physical evidence and eyewitness accounts), B (mostly based on natural traces), and C (least reliable based on equivocal evidence). Most physical evidence obtained after June was not significant; therefore, reliance was mostly placed on eyewitness accounts. Locations and relative heights above sea level were measured using handheld GPS receivers, auto-level, or total station. The measured heights were corrected for differences in tide level between measurement time and tsunami arrival time. The results are shown on table and four regional maps; however, the details of each measurement, including locations shown on 1:25,000 maps and photographs of evidence are shown in the Appendix. Along the northern Sanriku coast (Aomori and Iwate), most of the 141 heights range between 10m and 30m. Runup heights exceeding 30m were measured at one location in Noda Village and nine locations in Miyako City. On the southern Sanriku coast in Miyagi, most of the 76 measurements range between 4 and 20 m. On the Ibaraki coast, 36 measurements range from 2.8 to 8.1 m, and the heights generally decease toward the south. On the Chiba coast, 43 measurements range from 0.7 to 7.9 m, with the maximum height near Iioka, Asahi City.