Ultra efficient methods for modelling waveforms in seismic surveys

Research Project

Project/Area Number	13640425
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	固体地球物理学
Research Institution	Kyushu University
Principal Investigator	TAKENAKA Hiroshi Kyushu University, Faculty of Sciences, Associate Prof., 大学院・理学研究院, 助教授 (30253397)
Project Period (FY)	2001 – 2002
Project Status	Completed (Fiscal Year 2002)
Budget Amount *help	¥1,600,000 (Direct Cost: ¥1,600,000) Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Keywords	seismic exploration / elastic wave / seismic waveform / FDTD / 2.5-D / wave computation / plane wave / 人工地震質探査 / 弾性波動 / 地質波形 / 1次元構造 / 地震波 / スタガード格子
Research Abstract	In this study we developed efficient numerical methods for modeling seismic waveforms in seismic exploration. In the first year we developed a very efficient procedure to calculate plane-wave responses of arbitrary 1-D media, such as gradient velocity or randomly heterogeneous structures, using the finite-difference method in the time domain (FDTD). This may be useful for analysis of reflection survey or seismic logging data. In the second year we developed an ultra efficient method for modeling seismic waveforms in refraction or wide-angle reflection surveys. The most common form of seismic exploration remains a nearly linear survey with data acquisition lines including the source and receivers. For this situation we developed a 2.5-D modeling method for the simulation of 3-D seismic wavefields in media varying in two dimensions. The computer memory requirements and computation time are only slightly larger than those for 2D computations. We demonstrated the validity and efficiency of the technique with numerical examples, including a profile across a realistic model of subduction zone structure.