Nozomu Takeuchi (co-laboration with Minoru Kobayashi and Robert J. Geller)

Waveform inversion for detailed 3-D Earth structure is increasingly important approach for seismology.  Our group developed an accurate and efficient computational method, the Direct Solution Method (DSM; Geller & Takeuchi 1995 etc.), and waveform inversion based on accurate synthetic seismograms for 3-D heterogeneous Earth model became feasible.  Also, we recently developed a sophisticated data weigthing method to improve the resultant Earth model (see above figure).  Using these methods, we hope to reveal detailed elastic and anelastic properties of the Earth in the near future.

Available Resources

DSM softwares to compute synthetic seismograms are available: click here

References
Takeuchi N, Kobayashi M (2004).
     Improvement of Seismological Earth Models by Using Data Weighting in Waveform Inversion,
     GEOPHYS J INT, 158, 681-694.
Takeuchi N, Geller RJ (2003).
     Accurate Numerical Methods for Solving the Elastic Equation of Motion for Arbitrary Source Locations,
     GEOPHYS J INT, 154, 852-866.
Igel H, Takeuchi N, Geller RJ, et al. (2000).
     The COSY Project: verification of global seismic modeling algorithms,
     PHYS EARTH PLANET IN, 119, 3-23.
Takeuchi N, Geller RJ, Cummins PR (2000).
     Complete synthetic seismograms for 3-D heterogeneous Earth models computed using modified DSM operators and their applicability to inversion for Earth structure,
     PHYS EARTH PLANET IN, 119, 25-36.
Mizutani H, Geller RJ, Takeuchi N (2000).
     Comparison of accuracy and efficiency of time-domain schemes for calculating synthetic seismograms,
     PHYS EARTH PLANET IN, 119, 75-97.
Takeuchi N, Geller RJ (2000).
     Optimally accurate second order time-domain finite difference scheme for computing synthetic seismograms in 2-D and 3-D media,
     PHYS EARTH PLANET IN, 119, 99-131.
Geller RJ, Takeuchi N (1998).
     Optimally accurate second-order time-domain finite difference scheme for the elastic equation of motion: one-dimensional case,
     GEOPHYS J INT, 135, 48-62.
Cummins PR, Takeuchi N, Geller RJ (1997).
     Computation of complete synthetic seismograms for laterally heterogeneous models using the direct solution method,
     GEOPHYS J INT, 130, 1-16.
Takeuchi N, Geller RJ, Cummins PR (1996).
     Highly accurate P-SV complete synthetic seismograms using modified DSM operators,
     GEOPHYS RES LETT, 23, 1175-1178.
Geller RJ, Takeuchi N (1995).
     A new method for computing highly accurate DSM synthetic seismograms,
     GEOPHYS J INT, 123, 449-470.
Cummins PR, Geller RJ, Hatori T, Takeuchi N (1994).
     DSM complete synthetic seismograms - SH, spherically symmetrical, case,
     GEOPHYS RES LETT, 21, 533-536.
Cummins PR, Geller RJ, Takeuchi N (1994).
     DSM complete synthetic seismograms - P-SV, spherically symmetrical, case,
     GEOPHYS RES LETT, 21, 1663-1666.