Disposing of radioactive wastes in the deep ocean continues to be a research interest. Proponents explain the relative safety of geologically stable and biologically inactive deep ocean sediments that have accumulated for millions of years and are in the process of becoming sedimentary rocks.
This idea was enhanced by studies of sediment core recovered in October 1976 from an area nearly 1000 km north of Hawaii. Analysis showed that the lower portions of the 24-m-long core had been undisturbed for the last 70 million years. Earthquakes, volcanoes, ice ages, and tectonic plate movement did not affect the lower areas of sediment, which had a total thickness of at least 30 m.