Seismic Subsurface Exploration on the St. Lawrence River Project

The seismic method of subsurface exploration was used extensively by the Corps of Engineers, U. S. Army, in preliminary studies of the St. Lawrence River Project in the International Rapids Section. A well-defined interface between the glaciated rock and the overlying till made possible the determination of the depth of overburden with satisfactory accuracy. Considerable success was also attained in determining changes in the overburden. The program included tests in both quiet and swift water, for which special apparatus and methods were devised. The use of the seismic data enabled the design of concrete structures, navigation channels, and hydraulic cuts to proceed more rapidly than if exploration consisted only of drill holes.