Integrated seismic study of the Sudbury structure and surrounding area

A multi-offset 3-component VSP experiment was carried out to study the shallow seismic velocity structure in the center of the Sudbury Basin. In addition to obtaining realistic P- and S-waves velocity models through travel time inversion and WKBJ synthetic seismic modeling, the VSP experiment provides us with an independent estimation for the dip of the contact between the Chelmsford and Onwatin formations. The VSP-CDP transformed section and corridor stacked section correlate well with the high-resolution surface reflection data. The results indicate that the multi-offset three-component VSP experiment provides important constraints and auxiliary information for shallow crustal seismic studies.; The LITHOPROBE seismic regional reflection line 42 was reprocessed in this thesis research to image the subsurface structure northwest of the Sudbury Basin. Carefully designed traditional processing steps combined with time varying cross-dip correction and the wavelet transform for removal of the ground roll noise have dramatically enhanced the seismic reflection image, in contrast to the preliminarily processed data. The reprocessed LITHOPROBE Sudbury regional reflection line 42 data has successfully extended the reflection profile of the Sudbury area to approximately an additional 20 km northwest, and has revealed the subsurface structure in the Levack Gneiss Complex and surrounding area.; Two advanced data processing techniques were investigated theoretically and numerically implemented in this thesis. The time varying cross-dip correction algorithm developed for crooked line data processing has proved to be very effective for focusing reflection energy and imaging complex dipping structures with inconsistent cross-dips. The algorithm has also provided important information for cross-dip attitudes of the reflectors. The wavelet transform is a new digital signal processing technique which has an advantage of analyzing and localizing signals in both time and frequency domains simultaneously. In this thesis, a non-orthogonal wavelet transform algorithm was developed for seismic application and programmed for implementation of removing ground roll noise. The results indicate that the new approach is very effective and superior to the conventional f-k filtering method.; The high resolution refraction experiment explores a cross-array of two profiles with an approximate 285 km long line in the NW-SE direction and a 164 km long line in the W-E direction across the Abitibi Subprovince in the Superior Province, the Sudbury Structure, the Grenville Front Tectonic Zone, and the Britt Domain in the Grenville Province. The preliminary processed seismic refraction sections were interpreted by using the Cerveny's two point dynamic ray tracing and modeling algorithm. The computed travel times match well with the observed data for most phases including both head waves and wide-angle reflections. The results outline the major crustal and upper mantle structures for the study area. (Abstract shortened by UMI.)...