Two seamounts discovered
August 22, 1967
Two western Pacific submarine volcanoes, or seamounts, some 53 miles apart and considered among the largest yet discovered, have been found, charted, and named after two veteran marine technicians of the University of California, San Diego's Scripps Institution of Oceanography.
Dr. Harmon Craig, UCSD professor of geochemistry and scientific party leader of the Argo Leg 3 of Scripps' Nova Expedition to the southwest Pacific, has reported that the Dixon Seamount measured some 38 miles across the top and 13,100 feet high and that the Hohnhaus Seamount was about 3111 miles across and 12,400 feet tall.
They were named after Fred S. Dixon, of San Diego, who joined Scripps in 1955, and George W. Hohnhaus, of San Diego, who joined Scripps in 1953.
The two seamounts were discovered about 1,200 miles southwest of Hawaii, 60 miles east of the International Dateline, and halfway between Midway Island and the Fiji Islands.
The Dixon Seamount was charted at 12 degrees 33.3 minutes north latitude and 179 degrees 3.8 minutes west longitude and the Hohnhaus Seamount at 13 degrees 27.1 minutes north latitude and 179 degrees 10 minutes west longitude.
A typical Pacific submarine volcano approximating the height of the Dixon and Hohnhaus Seamounts is the Henderson Seamount, some 300 miles off Baja California, with an elevation of about 11,000 feet. On land, Mt. Rainier, in the State of Washington, has an elevation of 14,100 feet.
Seamounts are usually named after the first name of the wife of the scientific leader of an expedition. But, Dr. Craig explained, he had earlier had a seamount that he and Dr. H. W. Menard of Scripps discovered in the south Pacific during Scripps' Monsoon Expedition, in 1960-61, and that was named after Dr. Craig's wife, Valerie.
It was then decided to name the dual seamounts after Dixon, who was serving aboard Argo, and Hohnhaus, who was aboard another Scripps vessel, Horizon, 1,000 miles southward on another leg of the Nova Expedition.
"As Argo steamed south about midnight of June 23-24, we saw this great submarine volcano shaping up on the ship's precision depth recorder," Dr. Craig said.
"Six hours later another similar seamount appeared. We eventually realized it was taller than the first. We gave the Hohnhaus name to the first and Dixon's to the second."
Both seamounts were discovered in the same flat, abyssal plain. The Dixon rose from 18,000 feet to within 4,800 feet of the surface of the ocean.
Dr. Craig said extensive topographic and magnetic measurements of the Dixon were taken and that it was traversed six times in order to obtain accurately measurements with which to chart its magnetic polarity. "We hope to determine from these measurements when Dixon Seamount was formed, based on knowledge of changes in the earth's polarity millions of years ago," he said.
The naming of the seamounts was formalized at an Argo-Horizon magiti, in Suva, Fiji, attended by members of both crews and scientific parties when the two ships docked there before continuing joint Nova explorations farther south that are now in progress. A magiti corresponds to a Hawaiian luau, Dr. Craig said.