Tracking Ocean Storms with the Seismograph*

Abstract

The Microseismic Research Project described in this paper was started by the U. S. Navy in 1943 in an effort to find a better and cheaper method of locating and tracking severe tropical disturbances when several hundred miles from land. The microseismic data prove that a storm causes the ocean bottom over which it passes to vibrate and these more or less regular oscillations are called microseisms. They travel outward from the storm center in concentric circles and can be recorded on a microseismic seismograph. The amplitude of the microseisms recorded for a particular storm appears to depend principally on the storm's intensity and distance from a recording seismograph and to a less degree on the depth of the water over which it passes and on the position of certain deep discontinuities of the earth's crust. The maximum effective distance a storm can be detected in the Caribbean is about 600 miles while in the Pacific it is at least 1000 miles.