Faculty Profiles - WATANABE Toshiki

Papers - WATANABE Toshiki

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Time-lapse changes in tube and guided waves in cross-well Mallik experiment Reviewed International coauthorship International journal

Andrey Bakulin, Valeri Korneev, Toshiki Watanabe, Serge Ziatdinov

Society of Exploration Geophysicists - SEG International Exposition and 76tth Annual Meeting 2006, SEG 2006 page： 379 - 383 2018

Language：Japanese Publishing type：Research paper (international conference proceedings)

We analyze cross-well seismic data from the Mallik experiment and demonstrate time-lapse changes in tube and guided waves. Although such changes are challenging to interpret, they are generally of a larger magnitude compared to any time-lapse signatures of the first P-wave arrivals reported elsewhere. This suggests better sensitivity of tube and guided waves to small production-related changes and their feasibility for reservoir monitoring.

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2016年熊本地震と関連する活動に関する総合調査 Invited

清水洋, 松本聡, 酒井慎一, 岡田知己, 渡辺俊樹, 飯尾能久, 相澤広記, 松島健, 高橋浩晃, 中尾茂, 鈴木康弘, 後藤秀昭, 大倉敬宏, 山本希, 中道治久, 山中浩明, 神野達夫, 三宅弘恵, 纐纈一起, 浅野公之, 松島信一, 福岡浩, 若井明彦, 大井昌弘, 田村圭子, 木村玲欧, 井ノ口宗成, 前原喜彦, 赤星朋比古

自然災害科学総合シンポジウム講演論文集 Vol. 53 page： 73 - 90 2016.9

Development of surface-wave monitoring system for leaked CO2 using a continuous and controlled seismic source Reviewed

Tatsunori Ikeda, Takeshi Tsuji, Toshiki Watanabe, Koshun Yamaoka

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol. 45 page： 94 - 105 2016.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

To detect CO2 leakage from CO2 geological storage, we describe a seismic monitoring method using a continuous and controlled seismic source system, the Accurately Controlled Routinely Operated Signal System (ACROSS). The method applies surface-wave analysis to monitor the shallow subsurface from the temporal-variation (time-variation) of surface-wave phase velocity. Our numerical simulation study for CO2 leakage through fault zones indicated that the spatial distribution of leaked CO2 can be estimated from small temporal-variation of local phase velocities (similar to 1-3%). To demonstrate the method in a field case, we analyzed continuous seismic records acquired with ACROSS. We clearly extracted a dispersion curve of surface waves in the frequency range excited by the ACROSS (5.015-15.015 Hz). In particular, we obtained reliable estimates of phase velocities in 10-15 Hz frequency range, in which the time-variation of phase velocities was better than 1% accuracy. This temporal stability was sufficient to allow us to detect changes in phase velocities associated with CO2 leakage before leaked CO2 reached the surface. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijggc.2015.11.030

Web of Science

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A subsurface structure change associated with the eruptive activity at Sakurajima Volcano, Japan, inferred from an accurately controlled source Reviewed

Yuta Maeda, Koshun Yamaoka, Hiroki Miyamachi, Toshiki Watanabe, Takahiro Kunitomo, Ryoya Ikuta, Hiroshi Yakiwara, Masato Iguchi

GEOPHYSICAL RESEARCH LETTERS Vol. 42 ( 13 ) page： 5179 - 5186 2015.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

Temporal variations of Green functions associated with the eruptive activity at Sakurajima Volcano, Japan, were estimated using an accurately controlled routinely operated signal system (ACROSS). We deconvolved 400s waveforms of the ACROSS signal at nearby stations by a known source time function and stacked the results based on the time relative to individual eruptions and the eruption intervals; the quantities obtained by this procedure are Green functions corresponding to various stages of the eruptive activity. We found an energy decrease in the later phase of the Green functions in active eruptive periods. This energy decrease, localized in the 2-6s window of the Green functions, is difficult to explain by contamination from volcanic earthquakes and tremors. The decrease could be more reasonably attributed to a subsurface structure change caused by the volcanic activity.

DOI： 10.1002/2015GL064351

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弾性波アクロスによる東海地域地殻のP波およびS波速度構造の推定 Reviewed

國友孝洋, 山岡耕春, 渡辺俊樹, 吉田康宏, 勝間田明男, 生田領野, 加藤愛太郎, 飯高隆, 津村紀子, 大久保慎人

地震II Vol. 67 ( 1 ) page： 1 - 24 2014

Active monitoring at an active volcano: amplitude-distance dependence of ACROSS at Sakurajima Volcano, Japan Reviewed

Yamaoka, K., Miyamachi, H., Watanabe, T., Kunitomo, T., Michishita, T., Ikuta, R. and Iguchi, M.

Earth, Planets and Space 2014

Effects of pore fluid pressure and tectonic stress on diverse seismic activities around the Mt. Ontake volcano, central Japan Reviewed

Terakawa, T., Yamanaka, Y., Nakamichi, H., Watanabe, T., Yamazaki, F., Horikawa, S. and Okuda, T

Tectonophysics Vol. 608 page： 138 - 148 2013

東海地域下の三次元地震波減衰構造 Reviewed

高岡宏之, 津村紀子, 高橋福助, 野崎謙治, 加藤愛太郎, 飯高隆, 岩崎貴哉, 酒井慎一, 平田直, 生田領野, 國友孝洋, 吉田康弘, 勝俣啓, 山岡耕春, 渡辺俊樹, 山崎文人, 大久保慎人, 鈴木貞臣

地震第2輯 Vol. 65 ( 2 ) page： 175 - 187 2012.12

Imaging basement structure beneath the Noubi Plain, central Japan using strong motion records of natural earthquakes Reviewed

Watanabe, T., Shimizu, H., Tobita, J., Abe, S. and Shiraishi, K.

Proceedings of the 10th SEGJ International Symposium -Imaging and Interpretation- page： 96 - 99 2011.11

Monitoring the plate boundary in Tokai area using ACROSS -Role of Toyohashi ACROSS source-

Watanabe, T., Yamaoka, K., Yamazaki, K. and Suzuki, Y.

Proceedings of 14th International Symposium on Recent Advances in Exploration Geophysics page： 65 - 68 2010.11

Variations of fluid pressure within the subducting oceanic crust and slow earthquakes Reviewed

Kato, A., Iidaka, T., Ikuta, R., Yoshida, Y., Katsumata, K., Iwasaki, T., Sakai, S., Thurber, C., Tsumura, N., Yamaoka, K., Watanabe, T., Kunitomo, T., Yamazaki, F., Okubo, M., Suzuki, S. and Hirata, N.

Geophysical Research Letter Vol. 37 page： L14310 2010.7

Detection and continuous monitoring of strong seismic reflectors at the subducting Philippine Sea Plate using ACROSS methodlogy Reviewed

Kasahara, J, Tsuruga, K., Hasada, Y., Kunitomo, T., Ikuta, R., Watanabe, T., Yamaoka, K., Fujii, N. and Kumazawa, M.

Active Geophysical Monitoring, Vol. 40, Handbook of Geophysical Exploration page： 435 - 447 2010.5

構造境界面を組込んだMT法の2次元インバージョン Reviewed

木村俊則, 後藤忠徳, 笠谷貴史, 岡本拓, 三ケ田均, 真田佳典, 渡辺俊樹, 芦田讓

物理探査 Vol. 63 ( 2 ) page： 185 - 196 2010.4

Technical Trends on Seismic Reflection Method for Understanding Structure and Physical Properties in the Crust Invited Reviewed

Watanabe, T.

Zishin, Second Series Vol. 61 ( 特集号 ) page： S217 - S223 2009.7

Seismic interferometry of teleseicmic S-wave coda for retrieval of body waves: an application to the Philippine Sea slab underneath the Japanese Islands Reviewed

Tonegawa, T., Nishida, K., Watanabe, T. and Shiomi, K.

Geophysical Journal International Vol. 178 ( 3 ) page： 1183 - 1189 2009

Language：English Publishing type：Research paper (scientific journal)

In this study, we present the propagations of the body waves, such as direct P and S waves, and the reflected wave from the Philippine Sea slab, with the spatial correlation of thewavefields induced by teleseismic S wave observed at the Hi-net tiltmeters. The used frequency band is 0.07-0.5 Hz. To enhance the contribution of the S coda, we depressed the source-time function and the later deterministic phases, such as sS, ScS, SS, and surface wave. The cross correlation functions (CCFs) with the processed S coda are stacked by taking incident angle-dependence of direct S wave to stations into account for performing an isotropic incidence. Through these processes, the propagations of direct P, S, and reflected waves can be seen whenthe stacked CCFs are aligned as a function of separation distance between the two stations. The gradients of the travel time curves for the direct P and S waves are approximately 7 km/s and 3 km/s, corresponding to the seismic velocities in the crust (or uppermost mantle for the case of the P wave). In order to enhance the reflected waves, we search the reflected points by assuming that the later phases in the CCFs are SS reflections and mapping the amplitudes onto depth sections. As a result, the northerly-dipping negative phases can be traced right below the hypocenter distribution, probably corresponding to the oceanic Moho within the Philippine Sea slab. Moreover, we show that the oceanic Moho can be also traced by assuming the case of PP reflections. These results indicate that the CCFs plausibly contain the propagation information for both P and S waves between the two receivers, and are utilizable to the detections of reflected phases in addition to the direct waves.

DOI： 10.1111/j.1365-246X.2009.04249.x

2008年桜島人工地震探査の目的と実施

井口正人, 為栗健, 山本圭吾, 大島弘光, 前川徳光, 森済, 鈴木敦生, 筒井智樹, 今井幹浩, 封馬和希, 八木直史, 植木貞人, 中山貴史, 山本芳裕, 高木涼太, 猪井志織, 古賀祥子, 西村太志, Titi Anggono, 山本希, 及川純, 長出昇構, 市原美恵, 辻浩, 青木陽介, 森田裕一, 渡邊篤志, 野上健治, 山脇輝夫, 渡辺俊樹, 中道治久, 奥田隆, 立花健二, Enrique Hernandez, 橋田悠, 平井敬, 吉本昌弘, 山崎賢志, 毛利拓治, 清水洋, 中元真美, 山下裕亮, 三ケ田均, 尾西恭亮, 田中暁, 岡野豊, 川林徹也, 藤谷淳司, 坂口弘訓, 今泉光智哲, 大倉敬宏, 吉川慎, 安部祐希, 安藤隆志, 横尾亮彦, 相澤広記, 高山鐵朗, 山崎友也, 多田光弘, 市川信夫, 加茂正人, 富阪和秀, 宮町宏樹, 小林励司, 八木原寛, 平野舟一郎, 泊知里, 西山信吾, 吉田沙由美, 畠山謙吾, 西田誠, 加藤幸司, 宮村淳一, 小枝智幸, 増田与志郎, 平松秀行, 河野太亮, 松末伸一, 大薄富士男, 五藤大仁, 宮下誠, 伊藤弘志, 音成陽二郎

京都大学防災研究所年報 Vol. 52 ( B ) page： 293 - 307 2009

A marine deep-towed DC resistivity survey in a methane hydrate area, Japan Sea Reviewed

Goto, T., Kasaya, T. Machiyama, H., Takagi, R., Matsumoto, R., Okuda, Y., Satoh, M., Watanabe, T., Seama, N., Mikada, H., Sanada, Y. and Kinoshita, M.

Exploration Geophysics Vol. 39 ( 1 ) page： 52 - 59 2008.2

Time-variation of late arrivals in the transfer functions obtained by a permanent seismic source and receiver array (ACROSS)

Watanabe, T., Furukawa, T., Hasada, Y., Ikura, R., Yamaoka

Proceedings of the 12th International Symposium on Recent Advances in Exploration Geophysics page： 65 - 68 2008.1

Temporal change in reflected waves from deep crust possibly synchronized with the activity of DLFTs detected using ACROSS

Watanabe, T., Soma, T., Ikuta, R., Yamaoka, K.

Proceedings of the 11th International Symposium on Recent Advances in Exploration Geophysics page： 59 - 62 2007.4

東海監視に向けた地震波アクロスと小規模地震計アレイによる試験観測

渡辺俊樹, 生田領野, 相馬知征, 山岡耕春, 藤井直之,

月刊地球 Vol. 29 ( 8 ) page： 475 - 480 2007

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

プレート間カップリングの時間変化の監視を目的とする能動的な連続地震波観測を実現するために，弾性波アクロス震源と小規模地震計アレイを用いて10ヶ月にわたる試験観測を実施した．連続地震記録からアクロス伝達関数を求めた．その結果，地殻深部を伝播したと考えられる波群を検出し，それらの微小な時間変化を検知した．伝達関数の変化は低周波微動の活動と関連しているように見え，興味深い．地表に設置した地震計では気温，降雨などの地表付近の影響が避けられない．現在，ボアホール内に設置され環境変動の影響が小さいと考えられるHi-net記録を用いて，アレイ解析で見いだされた後続波群の時間変動について詳細に検討している．

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