INTER‐BOREHOLE ACOUSTIC MEASUREMENTS AND THEIR USE IN ENGINEERING GEOLOGY*

Abstract

A bstract Well–to‐well seismic measurements are adapted to civil engineering problems by use of a sparker as a source of seismic signals and an 80 kHz hydrophone as a receiver. For display a Tektronix 549 oscilloscope is used. Field application shows that the delineation of interfaces between homogeneous strata and the detection and delineation of localized and irregular features is possible from inter‐well travel times. In‐situ measurement of the compressional wave velocity in a medium is often complicated by refraction and wave guide effects. The degree of fracturing cannot be estimated from travel time measurements alone in a tightly jointed, saturated, rock mass, but it may be possible to correlate variations in pulse shape and length with this parameter.