Researchers with the U.S. Commerce Department's National Oceanic and Atmospheric Administration are using Hawaii's island of Oahu to obtain unique measurements of large‐scale water motions in the central North Pacific Ocean area.Three pairs of electrodes are planted in 105‐foot‐deep holes drilled down to the salt water, which underlies the island's fresh‐water table, on the grounds of NOAA–s Honolulu Observatory site at Ewa Beach. These buried sensors sense the electromagnetic fields produced by electrically conducting sea water moving in the earth's magnetic field. Scientists can translate these sensations into measurements of such large, relatively slow motions as tides, planetary waves, some types of turbulence, and