A method for planning continuity logging surveys and for detecting the presence of a continuous or discontinuous low-velocity
inclusion in a subterranean geological formation. To detect the presence of a continuous or discontinuous low-velocity inclusion,
a seismic source is inserted into a source borehole located at either a boundary or a center of a low velocity inclusion. Seismic
energy is generated coupled to the low-velocity inclusion using the seismic source. The seismic energy propagates as seismic
waves through the low-velocity inclusion and is measured and recorded by at least one detector disposed in a receiver
borehole. The seismic waves are analyzed for the presence of at least one seismic signature from which the distance of a
discontinuity, if any, of the low-velocity inclusion with respect to the receiver borehole can be determined.