研究者詳細 - 竹中　博士

MISC - 竹中　博士

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喜界島における1995年奄美大島近海地震余震の広帯域強震観測

藤井雄士郎, 奥村貴史, 竹中博士, 鈴木貞臣

地球惑星科学関連学会合同大会予稿集 1996 1996年

雲仙火山構造探査の延長測線

鈴木貞臣, 勝俣啓, 山崎義典, 三浪俊夫, 石原和彦, 竹中博士

地球惑星科学関連学会合同大会予稿集 1996 1996年

遠地地震波形データを用いた断層の検出 II マルチイベント,ノイズを含む波形への適用

村越匠, 竹中博士, 末次大輔

日本地震学会秋季大会講演予稿集 1996 1996年

3.9.1.6 地震波伝播の3次元数値シミュレーションに関する研究(3.9.1 関係機関との共同研究,3.9 共同研究,3. 研究業務)

藤原広行, 竹中博士

防災科学技術研究所年報 5 57 - 57 1995年3月

3.4.2(2) 不均質媒質における地震波伝播の理論並びにその地下構造推定への応用に関する研究(3.4.2 科学技術特別研究員,3.4 科学技術振興費による研究,3. 研究業務)

竹中博士

防災科学技術研究所年報 5 40 - 40 1995年3月

A wraparound elimination technique for the pseudospectral wave synthesis using an antiperiodic extension of the wavefield(共著)

FURUMURA T, TAKENAKA H

Geophysics 60 ( 1 ) 302 - 307 1995年1月

Modeling seismic wave propagation in complex media

H Takenaka

JOURNAL OF PHYSICS OF THE EARTH 43 ( 3 ) 351 - 368 1995年

記述言語：英語掲載種別：書評論文，書評，文献紹介等出版者・発行元：CENTER ACAD PUBL JAPAN

We review the studies on modeling seismic wave propagation in complex media, which were carried out during the past 10 years by researchers at Japanese institutions. Special emphasis is placed on those works which are perceived as important but had little exposure outside Japan. We can say that the fundamental development of method for seismogram synthesis in the (3, 1) dimension was completed, where the first and second numbers in parentheses are the space dimensions of the wavefield and the heterogeneity of the medium. However, seismologists have been eager to model seismic propagation in the (2, 2), (3, 2), and (3, 3) dimensions during the last 10 years. Modeling seismic wave propagation in a full (3, 3) dimension is now limited to simple small-scale problems because of the extensive computation and large memory, even when using a supercomputer. Nevertheless, in laterally and vertically heterogeneous media, we have to calculate 3-dimensional wavefields in order to analyze real seismic records quantitatively. There exist two potential breakthroughs. One is to assume the medium is axisymmetric and the other to model(3, 2) dimensional wave propagation (the so-called 2.5 dimensional problem). Numerical methods have the potential to simulate seismic wave propagation in realistic environments of substantial spatio-temporal extent. Since we are not used to processing such an abundance of information, we have to investigate methods for analyzing and interpreting large volumes of computational data. These studies may well challenge our conception of seismic wave propagation.

DOI： 10.4294/jpe1952.43.351

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Aftershock observation of the 1995 Hyogo-ken Nanbu earthquake in Awaje Island : strong motion and broad band observation(共著)

T. Okumura, H. Takenaka, S. Suzuki, T. Sasatani, M. Furumura, S. Saito, T. Matsushima, T. Furumura

Sci. Repts. , Dept. Earth & Planet. Sci. , Kyushu Univ. 19 ( 1 ) 103 - 123 1995年

The 1995 Hyogo-ken Nanbu earthquake occurred on January 17 1995. The maximum seismic intensity was seven in Kobe city and a part of Awaji island. The aftershocks were observed at three stations in Awaji island using three strong-motion seismometers and a broad-band seismometer from January 19 to April 4. During this period, 89 events were oberved. In these events, nine events were observed at all of the three stations. Among the nine events, three events were analysed using integration of velocity in the time domain and amplitude spectrum of S-wave for 5 seconds. Amplitude spectral ratios of two events occurring in Kobe side for 20 seconds from P-wave arrival, for 20 seconds from S-wave arrival, and S-wave part for 5 seconds were also analysed. Those amplitude spectra showed predominant frequency around 1-4 Hz for IWY and ABK stations, but TSM predominant frequency around 4-7 Hz. The spectral ratio shows 3-10 times amplification, around 1-2 Hz and 4-7 Hz for TSM/IWY, and around 0.9-2 Hz and 4-7 Hz for ABK/IWY. For TSM/IWY, 2-5 times attenuation was observed around 2-3 Hz.

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A wraparound elimination technique for the pseudospectral wave synthesis using an antiperiodic extension of the wavefield(共著)

T. Furumura, H. Takenaka

Geophysics 60 ( 1 ) 302 - 307 1995年

A simple but effective technique for wraparound elimination called antiperiodic extension is proposed. This technique is based on a simple modification of the wavefield. A brief description of the Fourier differentiation and wraparound phenomenon are given. Two methods for elimination of wraparound are then compared. The first is based on Cerjan's method, and the second on the concept of Fourier differentiation for an antiperiodically extended wavefield as developed in this note. To demonstrate the validity of the present technique, it is applied to 2-D elastic modeling (P-SV case) of a syncline structure where an explosive-type source is considered. -from Authors

DOI： 10.1190/1.1443760

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淡路島における1995年兵庫県南部地震の余震観測-強震動及び広帯域余震観測-（共著）

九州大学理学部研究報告(地球惑星科学) 19 ( 1 ) 103 - 123 1995年

Treatment of an infinitely extended free surface for indirect formulation of the boundary element method(共著)

J. Phys. Earth 43 ( 1 ) 79 - 103 1995年

Modeling seismic wave propagation in complex media

Hiroshi Takenaka

Journal of Physics of the Earth 43 ( 3 ) 351 - 368 1995年

記述言語：英語

We review the studies on modeling seismic wave propagation in complex media, which were carried out during the past 10 years by researchers at Japanese institutions. Special emphasis is placed on those works which are perceived as important but had little exposure outside Japan. We can say that the fundamental development of method for seismogram synthesis in the (3, 1) dimension was completed, where the first and second numbers in parentheses are the space dimensions of the wavefield and the heterogeneity of the medium. However, seismologists have been eager to model seismic propagation in the (2, 2), (3, 2), and (3, 3) dimensions during the last 10 years. Modeling seismic wave propagation in a full (3, 3) dimension is now limited to simple small-scale problems because of the extensive computation and large memory, even when using a supercomputer. Nevertheless, in laterally and vertically heterogeneous media, we have to calculate 3-dimensional wavefields in order to analyze real seismic records quantitatively. There exist two potential breakthroughs. One is to assume the medium is axisymmetric and the other to model (3, 2) dimensional wave propagation (the so-called 2.5 dimensional problem). Numerical methods have the potential to simulate seismic wave propagation in realistic environments of substantial spatio-temporal extent. Since we are not used to processing such an abundance of information, we have to investigate methods for analyzing and interpreting large volumes of computational data. These studies may well challenge our conception of seismic wave propagation. © 1995, The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan. All rights reserved.

DOI： 10.4294/jpe1952.43.351

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Treatment of an infinitely extended free surface for indirect formulation of the boundary element method(共著)

Toshiaki Yokoi, Hiroshi Takenaka

J. Phys. Earth 43 ( 1 ) 79 - 103 1995年