According to the United States Geological Survey, the descriptive name, Trident, was given by Robert Fiske Griggs of the National Geographic Society, in 1916, because there were three major peaks.

A satellite cone formed February 15, 1953 on the southwest flank of Trident following a major explosive eruption that sent ash to an altitude of over 5.6 miles (9.0 km).

In 1983, steam and/or vapor continued to rise from the central vent area of the new cone as well as from numerous fumaroles on the near-vent portion of the blocky lava flows.

The dominant phenocrysts are zoned plagioclase, hypersthene, calcic clinopyroxene, titanomagnetite, and rimmed olivine.

The five flows which erupted from the new vent during the period from 1953 to 1963 are olivine-bearing, two pyroxene, high-silica andesite.