SUBSURFACE IMAGING USING CROSSHOLE TOMOGRAPHIC METHODS1

Crosshole seismic tomography experiments were performed to image the subsurface structure between pairs of wells in three locations at Ano Liosia Municipality. Seismic caps were used as downhole sources and a 24-channel geophone cable provided the downhole receivers. The crosshole data were processed with a SIRT traveltime transmission tomography package to produce a velocity model. The crosshole velocity section exhibits rapid lateral and vertical velocity changes that are not resolved by surface methods. The results indicate that crosshole tomography can potentially be used to image steeply dipping beds or complex structures, such as small faults or cavities