Robust tomography using wide-band Fresnel zone wavepath
Bagus E. B. Nurhandoko
Department of Earth and Resources Engineering, Kyoto University, Japan.
E-mail: bagus@tansa.kumst.kyoto-u.ac.jp
Abstract
In the present paper, we introduce a new algorithm for Fresnel zone
wavepath inversion that considers wide band wave spectra. So, the inversion
is done by using wide-band spectra rather than narrow spectra
(monochromatic), because the natural wave spectra are polychromatic rather
than purely monochromatic. And mathematically, the monochromatic wavelet
also means that the wavelet is infinite in time domain. Practically,
however, real seismic field data are finite in time domain. Therefore, the
frequency spectrum
would be better represented as a distribution of polychromatic spectra
rather than mono spike spectrum.
The frequency parameter used in this inversion method sweeps from low to
high frequencies. By this sweeping frequency procedure, we get more accurate
estimation and wide angle in reconstruction.
By the model studies, this inversion method is robust in both dense and
sparse data, even though the initial model is quite far from the true model.
This method also provides better in reconstruction than raypath tomography.
Nevertheless, this method still provides faster computation than the raypath
tomography.
raeg99@tansa.kumst.kyoto-u.ac.jp
Last modified: Mon Nov 29 15:16:39 1999