A small seismic system (Mini-Sparker) has been developed to use frequencies in the 200-2,000 Hz band for highly detailed marine profiling. Reflections down to 500- to 800-ft depths are recorded in clastic sediments, with resolution of 6-8 ft.

The Mini-Sparker profile is recorded as a single channel on facsimile paper. The equipment is man-portable, and the acoustic source is equally effective in freshwater or saltwater areas.

A procedure has been developed for high resolution recording at variable offsets between source and receiver, thus providing the information for a T² - X² computation of average velocities to various reflection levels.

Examples illustrated include profiles from (1) a freshwater lake in a glaciated area, (2) the Gulf Coast continental shelf, and (3) the North Sea. The first and last examples include velocity-determination sections as well as structure sections.

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