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Kirita, Fumio; Tominaga, Masahiro; Yamazaki, Toshihiko; Seshimo, Kazuyoshi; Uryu, Mitsuru
JAEA-Research 2022-006, 61 Pages, 2023/02
Nuclear Fuel Cycle Engineering Laboratories (NCL) has been observing ground motion for a long time. On the border from northern Ibaraki prefecture to Fukushima prefecture, inland crustal earthquakes occur less frequently until the 2011 off the Pacific coast of Tohoku Earthquake (hereinafter referred to as Tohoku Earthquake). After Tohoku Earthquake, aftershocks have become more frequent in this area, and in the Hamadori region of Fukushima earthquake that a remarkable long periodic component was observed in the NCL seismic observation record. Until now there were no such things that long periodic components were observed at the observation points near the epicenter of April 2011 Fukushima earthquake, but it was thought basin structure in deep basement around the NCL affected the propagation process to NCL by reflection survey result. As basement structure of NCL affected the seismic wave propagation process, the seismic wave repeatedly reflects and refracts. For that reason, long periodic components of seismic waves may be possibly amplified. In this study, in order to refine the long periodic ground motion evaluation, using a three dimensional ground structure model (3D model) that can reflect the shape of the deep basement structure around the NCL. When modeling 3D ground structure which has a width of about 80km and a length of about 110km and ranges from the epicenter area of April 2011 Fukushima earthquake to the northern coastal area of Ibaraki prefecture modeled, improved the optimum ground structure model using multiple observation records and performed simulation analysis.
Kirita, Fumio; Kanazawa, Kenji*; Kitamura, Haruyuki*
Proceedings of 14th World Conference on Earthquake Engineering (WCEE-14) (CD-ROM), 8 Pages, 2008/10
This paper presents a new system identification procedure for a time-varying system to estimate natural frequency transition of a building from a strong seismic motion record, named as "Adaptive Forward-Backward Kalman Filter (AFB-KF)". The AFB-KF is compared to the conventional Kalman Filter in the below three points: (1) Forgetting factor for covariance functions to track time-varying structural parameters rapidly, (2) Time-backward estimation scheme and global iteration scheme of the forward and backward processes to estimate unknown initial value of structural parameters, (3) The time series renewal algorithm of statistical properties by reflecting the previous analysis information to improve the identification accuracy. It is useful to accurately identify from natural frequency transition of a building during an earthquake for structural health monitoring which evaluates structural integrity.
Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko; Nakanishi, Ryuji
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Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko; Hashimura, Hirohiko; Nakanishi, Ryuji; Kojima, Keidai
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Nakanishi, Ryuji; Uryu, Mitsuru; Yamazaki, Toshihiko; Hashimura, Hirohiko; Kirita, Fumio; Kojima, Keidai
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Hashimura, Hirohiko; Uryu, Mitsuru; Yamazaki, Toshihiko; Nakanishi, Ryuji; Kirita, Fumio; Kojima, Keidai
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Hashimura, Hirohiko; Uryu, Mitsuru; Yamazaki, Toshihiko; Nakanishi, Ryuji; Kirita, Fumio; Kojima, Keidai
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Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko; Hashimura, Hirohiko; Nakanishi, Ryuji; Kojima, Keidai
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Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko; Hashimura, Hirohiko; Nakanishi, Ryuji; Kojima, Keidai
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Kojima, Keidai; Uryu, Mitsuru; Yamazaki, Toshihiko; Hashimura, Hirohiko; Nakanishi, Ryuji; Kirita, Fumio
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Nakanishi, Ryuji; Uryu, Mitsuru; Yamazaki, Toshihiko; Hashimura, Hirohiko; Kirita, Fumio; Kojima, Keidai
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Uryu, Mitsuru; Kirita, Fumio; Yamazaki, Toshihiko; Hashimura, Hirohiko; Nakanishi, Ryuji; Kojima, Keidai
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Yuzawa, Yutaka*; Uryu, Mitsuru; Yamazaki, Toshihiko; Kirita, Fumio; Mashimo, Mitsugu*
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Yasuda, Masahiro; Uryu, Mitsuru; Yamazaki, Toshihiko; Kirita, Fumio; Fujihara, Satoru*; Kawaji, Kaoru*
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Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko
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Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko; Yasuda, Masahiro; Fujihara, Satoru*; Kawaji, Kaoru*
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Fujihara, Satoru*; Kirita, Fumio; Kawaji, Kaoru*; Yamazaki, Toshihiko; Uryu, Mitsuru; Yasuda, Masahiro
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Kirita, Fumio; Uryu, Mitsuru; Yamazaki, Toshihiko; Fujihara, Satoru*; Kawaji, Kaoru*
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Fujihara, Satoru*; Uryu, Mitsuru; Yamazaki, Toshihiko; Kirita, Fumio; Kawaji, Kaoru*
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Fujihara, Satoru*; Kirita, Fumio; Kawaji, Kaoru*; Yamazaki, Toshihiko; Uryu, Mitsuru
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no abstracts in English