SOME RECENT ADVANCES IN OFFSHORE REGIONAL RECONNAISSANCE GEOPHYSICAL SURVEY METHODS

Abstract

Traditional geophysical methods in use offshore include the airborne magnetometer, underwater gravity meter, and seismic reflection with 24-channel recording and large explosive energy source. Navigation is by range-range and hyperbolic phase-comparison radio systems set up as local networks. Other methods now being used include towed magnetometer, surface gravity meter, and automatic continuous seismic profilers, and all three methods can be used for simultaneous recording from a single recording boat. Navigation systems not requiring local networks include satellite radio doppler, very low frequency phase measurement and sonar doppler devices. These may be used word-wide and 24 hours per day. A single recording boat may thus be virtually self-sufficient. The Bureau of Mineral Resources plans a survey for 1967 that will use a number of these geophysical methods and navigation aids.