Variations in Seismic Properties of Flood Basalts from Shallow Refraction Seismic Analysis

This work aims to contribute to the overall objective of a better understanding of the seismic properties of basalts and the development of better velocity models for basalts. The objective of this work was to establish the applicability of shallow surface-seismic travel-time tomography in basalt-covered areas. We tested many inversion sequences while varying the inversion parameters. Modelled travel times were verified by full-waveform modelling. Zero-offset VSP, VP, VS and density logs, downhole-geophone recordings and previous geological mapping in the area provided good means of control. We show that the method relates detailed seismic properties to different types of basaltic rock and we provide inversion parameters for shallow tomography in a basalt-covered area with high velocities and high velocity contrasts.