Faculty Profiles - TAKENAKA Hiroshi

A two-point, three-dimensional seismic ray tracing using genetic algorithms

H Sadeghi, S Suzuki, H Takenaka

PHYSICS OF THE EARTH AND PLANETARY INTERIORS 113 ( 1-4 ) 355 - 365 1999.6

Language：English Publisher：ELSEVIER SCIENCE BV

DOI： 10.1016/S0031-9201(99)00011-4

Broadband strong-motion observation on the hard rock site at Kushikino.

Synthetic seismograms by using the pseudosepctral method(6) : An efficient differentiation operator for large scale 3D parallel computing

FURUMURA Takashi, KOKETSU Kazuki, TAKENAKA Hiroshi

100 103 - 107 1999.6

20 ( 3 ) 89 - 98 1999

鹿児島県串木野市の岩盤上における広帯域強震観測(共著)

九大理学部研究報告(地球惑星) 20 ( 3 ) 79 - 88 1999

地震トモグラフィによる九州背弧のマントル・アップウエリング構造と九州の張力場(共著)

月刊地球 ( 号外27 ) 211 - 216 1999

速度-応力型スタガード格子差分法を用いた2次元及び3次元地震波動計算コードの作成(共著)

九州大学理学部研究報告(地球惑星科学) 20 ( 3 ) 99 - 110 1999

Seismograph orientation at K-NET observatories (1) : Western Kagoshima region

TAKENAKA Hiroshi, WATANABE Atsushi, FUJIWARA Hiroyuki

Sci. Repts., Dept. Earth & Planet. Sci., Kyushu Univ. 20 ( 3 ) 89 - 98 1999

Broadband strong-motion of observation on hard rock site at Kushikino

Atsushi Watanabe, Yushiro Fujii, Hayato Futamure, Nobuki Kame, Hiroshi Takenaka, Sadaomi Skuzuki, Kenji Uehira, Takeshi Matsushima

Sci. Repts., Dept. Earth & Planet. Sci., Kyushu Univ. 20 ( 3 ) 79 - 88 1999

In 1997, two moderate earthquakes occurred in the northwestern part of Kagoshima Prefecture (Mjma 6.5 on March 26 and Mjma 6.3 on May 13), and a large number of aftershocks occurred in the southern part of the second event focal region. We started the observation of the aftershocks from April 1, 1998, at Kushikino. We used a broadband strong-motion velocity-type seismograph and an accelerograph in order to record the full waveforms of the strong ground motions. Up to April 25, 1999, we observed 74 events, and 3 events were recorded by both seismographs. In this paper, we report the detail of observational conditions and show some waveforms we obtained.

Scopus

Simulating seismic wave propagation in transversely isotropic media by using pseudo-spectral method(共著)

Northwestern Seismological Journal 21 ( 2 ) 212 - 224 1999

Development of 2D and 3D codes of the velocity-stress staggered-grid finite-difference method for modeling seismic wave propagation

HAYASHIDA T.

Science Reports, Department of Earth and Planetary Sciences, Kyushu University 20 ( 3 ) 99 - 110 1999

Simulating seismic wave propagation in transversely isotropic media by using pseudo-spectral method(共著)

Northwestern Seismological Journal 21 ( 2 ) 212 - 224 1999

An efficient approach of the pseudospectral method for modelling of geometrically symmetric seismic wavefield

H Takenaka, YB Wang, T Furumura

EARTH PLANETS AND SPACE 51 ( 2 ) 73 - 79 1999

Language：English Publisher：TERRA SCIENTIFIC PUBL CO

The pseudospectral method is a high-accuracy numerical modelling technique that requires less computer memory and computation time than the traditional techniques such as the finite-difference method. These advantages of the pseudospectral method have enabled us to practically apply this method to modelling realistic problems that have complex structure and source models. However, a major drawback of such numerical schemes for discrete grid models is that even for rather a simple structural model they require as much computational requirements (e.g. computation time and memory) as for an entirely complex structural model with the same size of the simple one. We actually need to employ idealised simple models, such as a model with geometrical symmetry, to investigate basic phenomena of seismic waves, to develop new techniques, or to choose optimal values of some computational parameters for more complex modelling. In this paper we propose an efficient approach of an economical pseudospectral method for calculation of wavefields in models symmetric with respect to a vertical plane or two orthogonal vertical planes. Using this approach, the wavefields only need to be computed in a half or quarter domain of the models, so that the computer memory and computation time can be reduced ideally by half or quarter, respectively, as compared with the calculation of the entire models.

DOI： 10.5636/eps.51.73

An efficient approach of the pseudospectral method for modelling of geometrically symmetric seismic wavefield

H Takenaka, YB Wang, T Furumura

EARTH PLANETS AND SPACE 51 ( 2 ) 73 - 79 1999

Language：English Publisher：TERRA SCIENTIFIC PUBL CO

DOI： 10.5636/eps.51.73

1995年兵庫県南部地震余震の地震核 (総特集地震発生に伴う物理現象--地震発生の場と物理過程(2))

マルチバンドパスフィルターを用いたS波最大振幅解析による地震波放射特性の周波数依存に関する考察

侭田豊, 二牟礼勇人, 竹中博士

日本地震学会秋季大会講演予稿集 1999 1999

PSM/FDMハイブリッド型並列計算による地震波動の3次元数値シミュレーション

古村孝志, こうけつ一起, 竹中博士

日本地震学会秋季大会講演予稿集 1999 1999

スタガード格子差分法を用いた3次元弾性波動モデリングにおける新しい自由表面条件の適用

林田智宏, 竹中博士, 岡元太郎

日本地震学会秋季大会講演予稿集 1999 1999

Calculation of Seismic Wave Propagation in a Transversely Isotropic Cylindrical Earth Model by the Pseudospectral Method

WANG Yanbin, TAKENAKA Hiroshi, FURUMURA Takashi

1998 ( 2 ) 1998.10

奥村貴史, 鈴木貞臣, 竹中博士

月刊地球 20 ( 10 ) 648 - 653 1998.10

Parallel 3-D pseudospectral simulation of seismic wave propagation

T Furumura, BLN Kennett, H Takenaka

GEOPHYSICS 63 ( 1 ) 279 - 288 1998.1

Language：English Publisher：SOC EXPLORATION GEOPHYSICISTS

Three-dimensional pseudospectral modeling for a realistic scale problem is still computationally very intensive, even when using current powerful computers. To overcome this, we have developed a parallel pseudospectral code for calculating the 3-D wavefield by concurrent use of a number of processors. The parallel algorithm is based on a partition of the computational domain, where the field quantities are distributed over a number of processors and the calculation is concurrently done in each subdomain with interprocessor communications. Experimental performance tests using three different styles of parallel computers achieved a fairly good speed up compared with conventional computation on a single processor: maximum speed-up rate of 26 using 32 processors of a Thinking Machine CM-5 parallel computer, 1.6 using a Digital Equipment DEC-Alpha two-CPU workstation, and 4.6 using a cluster of eight Sun Microsystems SPARC-Station 10 (SPARC-10) workstations connected by an Ethernet. The result of this test agrees well with the performance theoretically predicted for each system. To demonstrate the feasibility of our parallel algorithm, we show three examples: 3-D acoustic and elastic modeling of fault-zone trapped waves and the calculation of elastic wave propagation in a 3-D syncline model.

DOI： 10.1190/1.1444322