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Interpretation of shallow refraction seismic data by reflection/refraction tomography [Note 1. Received October 1997, revision accepted April 1999. ...]
Author(s) -
Ditmar Pavel,
Penopp Jan,
Kasig Rainer,
Makris Jannis
Publication year - 1999
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1046/j.1365-2478.1999.00168.x
Subject(s) - inversion (geology) , geology , tomography , refraction , seismic refraction , vertical seismic profile , economic geology , seismic inversion , environmental geology , seismology , algorithm , computer science , geometry , optics , volcanism , tectonics , physics , mathematics , azimuth
A new algorithm for tomographic inversion of traveltimes of reflected and refracted seismic waves is developed. The inversion gives interface configurations and velocity distributions in layers. The important features of the algorithm are: (a) the inclusion of shot time delays in the list of unknown parameters; (b) the regularization is applied in such a way that the most probable model is characterized by the similarity of neighbouring interfaces. As the problem under consideration is non‐linear, several iterations are necessary in order to obtain the final model. In the case of a very inexact initial model, a ‘layer‐by‐layer’ inversion strategy is recommended as a first inversion step. The inversion program is supplied with a user interface, thanks to which one can: (a) pick interactively and identify seismic traveltimes; (b) build and edit depth/velocity models; and (c) display calculated traveltime curves and compare them with picked traveltimes as well as with the original seismic sections. The efficiency of the inversion software developed is illustrated by a numerical example and a field example in which shallow seismic data are considered. Application to wide‐aperture reflection/refraction profiling (WARRP) data is also possible.