The geologic structure of the Puna submarine ridge, Hawaii

Abstract

Magnetic and bathymetric surveys over the seaward extension of the Puna rift zone, which is located above the Puna ridge from the Kilauea dome and extends for nearly 70 km northeast of Cape Kumukahi, Hawaii, show that the submarine extension of the zone over the Puna submarine ridge is characterized by an elongate, normally polarized magnetic anomaly of maximum amplitude of 2270 gammas. The anomaly represents a zone of magnetized intrusive rock intruded into the submarine ridge and varying from 4 to 6 km in width. The magnetized intrusive rocks originate at an average depth of 1000 meters below the crest of the ridge. Rocks of the intrusive zone beneath the ridge appear to be connected with intrusive rocks beneath the Kilauea caldera at a shallow depth and with intrusive rocks beneath Mauna Loa through a deep rift zone.