The seamounts are composed out of basaltic and other rocks and their ages range from about 2.5 million years ago to latest Pleistocene; an acoustic swarm recorded in the southern Pacific Ocean in 1991-1992 is considered to be the manifestation of a historical eruption of the Hollister Ridge.

The eastern ridge is 70 kilometres (43 mi) long and rises to a depth of 1,400 metres (4,600 ft) below sea level, the central ridge is 207 kilometres (129 mi) long and rises to a depth of 100 metres (330 ft) below sea level, the western ridge is 50 kilometres (31 mi) long and rises to a depth of 1,500 metres (4,900 ft) below sea level.

[6] The ridge rises from a seafloor whose age decreases from 7-8 to 0-1 million years ago southeastward.

The basalts range from aphyric to porphyric and contain phenocrysts of olivine and plagioclase.

[14] Between 10 March 1991 and 12 June 1992 a strong acoustic swarm was recorded in the southern Pacific Ocean from several stations in French Polynesia[24] and its source identified with a segment of the Hollister Ridge.