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436 results on '"Ito, Yosuke"'

167. Temporal Variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$Above a Megathrust Following Episodic Slow‐Slip Events

Author

Ito, Yosuke and Nakajima, Junichi

Abstract

Recent observations beneath central Japan have shown that periodic fluid drainage occurs during slow‐slip events (SSEs) based on temporal variations in QP−1${Q}_{P}^{-1}$above the megathrust boundary of the subducting Philippine Sea slab. However, no previous studies have estimated associated QS−1${Q}_{S}^{-1}$. A comparison of QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$can provide clues to the mechanism of seismic attenuation because of different propagation characteristics of the two waves. We estimate temporal variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$via spectral analyses of waveform data from November 2009 to August 2021 period. The results indicate that both QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$exhibit temporal variations at about 1‐year periodicity and there are systematic differences between QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$that QS−1${Q}_{S}^{-1}$have smaller values, less insignificant variation, and weaker correlations with SSEs. Furthermore, QP−1/QS−1${Q}_{P}^{-1}/{Q}_{S}^{-1}$increases concurrent with SSEs. These differences suggest that attenuation is caused by the wave‐induced fluid flow. QP−1/QS−1${Q}_{P}^{-1}/{Q}_{S}^{-1}$could be an important parameter for detecting the presence of fluid. Q−1${Q}^{-1}$value, which represents energy dissipation of seismic wave, is an important parameter for detecting the anelastic heterogeneity in subsurface rocks. However, few observational studies have revealed the characteristics of both P‐ and S‐wave attenuation (QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$, respectively) related to the presence of fluids in the crust and the uppermost mantle. This study reveals that both QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$show temporal variations associated with the inferred periodic drainage from the upper surface of a subducting slab but QS−1${Q}_{S}^{-1}$is less fluctuated with time. We discuss a possible attenuation mechanism focusing on the differences in the observed QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$values and propose that the wave‐induced fluid flow (WIFF) may be a dominant control on the increases in attenuation concurrent with the drainage from the megathrust. The obtained results will provide important constraints on attenuation mechanism that is enhanced by the presence of fluid in rocks. We estimated the long‐term temporal variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$at 20–45 Hz above the megathrust boundary of the Philippine Sea PlateBoth QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$exhibited temporal variations with about 1‐year periodicity and spatiotemporal correlations with slow‐slip eventsSystematic differences between QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$may provide important constraints on attenuation mechanism enhanced by fluids We estimated the long‐term temporal variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$at 20–45 Hz above the megathrust boundary of the Philippine Sea Plate Both QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$exhibited temporal variations with about 1‐year periodicity and spatiotemporal correlations with slow‐slip events Systematic differences between QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$may provide important constraints on attenuation mechanism enhanced by fluids

Published
2023
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182. DEVELOPMENT OF TECHNOLOGY EDUCATION FOR SECONDARY SCHOOL WITH EARTH OBSERVATION TECHNIQUE

Author

Ito, Yosuke, Teramoto, Yuhei, and Abe, Kenji

Subjects
ComputingMilieux_COMPUTERSANDEDUCATION
Abstract

In this research, we propose to introduce earth observation technique using synthetic aperture radar (SAR) to secondary education. Our purpose is that learners are interesting and raise awareness for the earth observation technique through practical activities. Teaching program is planned based on a result of questionnaire surveys to school teachers. The program is composed of 16 units. Teaching materials with the earth observation technique are researched and developed. We design a visual SAR processor and a small corner reflector (CR) from educational points of view as a new type of teaching materials. In teaching practices at secondary school, the developed teaching materials and software were utilized effectively. In the observation experiments, the learners set up the CRs produced by themselves and ALOS PALSAR was able to observe all the CRs correctly. It was clarified that the learners understood the usefulness of the earth observation technique in the proposed technology education., 形態: カラー図版あり, 形態: DVD-ROM1枚, Physical characteristics: Original contains color illustrations, Note: One DVD-ROM, 資料番号: AA0065135149, レポート番号: JAXA-SP-11-007E

Published
2011

183. Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface

Author

Uchimura, Taro, primary, Towhata, Ikuo, additional, Lan Anh, Trinh Thi, additional, Fukuda, Jou, additional, Bautista, Carlos J. B., additional, Wang, Lin, additional, Seko, Ichiro, additional, Uchida, Taro, additional, Matsuoka, Akira, additional, Ito, Yosuke, additional, Onda, Yuichi, additional, Iwagami, Sho, additional, Kim, Min-Seok, additional, and Sakai, Naoki, additional

Published
2009
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192. BI-1-7 Space gravitational wave detector : DECIGO & DPF

Author

Musha, Mitsuru, Kawamura, Seiji, Ando, Masaki, Seto, Naoki, Sato, Shuichi, Nakamura, Takashi, Tsubono, Kimio, Takashima, Takeshi, Funaki, Ikko, Numata, Kenji, Kanda, Nobuyuki, Tanaka, Takahiro, Ioka, Kunihito, Aoyagi, Kosuke, Wagatsuma, Kazuhiro, Asada, Hideki, Aso, Yoichi, Arai, Koji, Araya, Akito, Ikegami, Takeshi, Ishikawa, Takehiko, Ishizaki, Hideharu, Ishidoshiro, Koji, Ishihara, Hideki, Izumi, Kiwamu, Ichiki, Kiyotomo, Ito, Hiroyuki, Ito, Yosuke, Inoue, Kaiki, Ueda, Akitoshi, Ueda, Kenichi, Utashima, Masayoshi, Ejiri, Yumiko, Enoki, Motohiro, Ebisuzaki, Toshikazu, Eriguchi, Yoshiharu, Oishi, Naoko, Okawa, Masashi, Ohashi, Masatake, Ohara, Kenichi, Obuchi, Yoshiyuki, Okada, Kenshi, Kawashima, Nobuki, Kawazoe, Fumiko, Kono, Isao, Kiuchi, Kenta, Kishimoto, Naoko, Kuninaka, Hitoshi, Kunimori, Hiro, Kuroda, Kazuaki, Koizumi, Hiroyuki, [checking], Kori, Kazunori, Kokuyama, Wataru, Kokeyama, Keiko, Kozai, Yoshihide, Kojima, Yasufumi, Kotake, Kei, Kobayashi, Shiho, Saijo, Motoyuki, Saito, Ryo, Sakai, Shinichiro, Sakagami, Masaaki, Sakata, Shihori, Sago, Norichika, Sasaki, Takashi, Sato, Takashi, Shibata, Masaru, Shinkai, Hisaaki, Sugiyama, Naoshi, Suzuki, Rieko, Suwa, Yudai, Somiya, Kentaro, Sotani, Hajime, Takano, Tadashi, Takahashi, Kakeru, Takahashi, Keitaro, Takahashi, Tadayuki, Takahashi, Hirotaka, Takahashi, Fuminobu, Takahashi, Ryuichi, Takahashi, Ryutaro, Takamori, Akiteru, Tagoshi, Hideyuki, Tashiro, Hiroyuki, Taniguchi, Keisuke, Taruya, Atsushi, Chiba, Takeshi, Tsujikawa, Shinji, Tsunesada, Yoshiki, Toyoshima, Morio, Torii, Yasuo, Naito, Isao, Nakao, Kenichi, Nakazawa, Kazuhiro, Nakasuka, Shinichi, Nakano, Hiroyuki, Nagano, Shigeo, Nakamura, Koji, Nakamura, Masaharu, Nakayama, Yoshinori, Nishizawa, Atsushi, Nishida, Erina, Nishiyama, Kazutaka, Niwa, Yoshito, Nomi, Taiga, Hashimoto, Tatsuaki, Hayama, Kazuhiro, Harada, Tomohiro, Hikita, Wataru, Himemoto, Yoshiaki, Hirabayashi, Hisashi, Hiramatsu, Naoshi, Fukushima, Mitsuhiro, Fujita, Ryuichi, Fujimoto, Masakatsu, Futamase, Toshifumi, Hosokawa, Mizuhiko, Horisawa, Hideyuki, Maeda, Keiichi, Matsuhara, Hideo, Mino, Yasushi, Miyagawa, Osamu, Miyamoto, Umpei, Miyoki, Shinji, Mukoyama, Shinji, Morisawa, Yoshiyuki, Morimoto, Mutsuko, Moriwaki, Shigenori, Yagi, Kento, Yamakawa, Hiroshi, Yamazaki, Toshitaka, Yamamoto, Kazuhiro, Yokoyama, Junichi, Yoshida, Shijun, Yoshino, Taizo, Wakabayashi, Yaka, and Sun, Ke-Xun

Abstract

本文データは学協会の許諾に基づきCiNiiから複製したものである

Published
2010

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