Terevaka formed around 0.77 Ma of tholeiitic to alkali basalts, followed by the collapse of its summit into a caldera. Then at about 0.3Ma, cinder cones formed along a NNE-SSW trend on the western rim, while porphyritic benmoreitic lava filled the caldera, and pahoehoe flowed towards the northern coast, forming lava tubes, and to the southeast. Lava domes and a vent complex formed in the Maunga Puka area, while breccias formed along the vents on the western portion of Rano Aroi crater. This volcano's southern and southeastern flanks are composed of younger flows consisting of basalt, alkali basalt, hawaiite, mugearite, and benmoreite from eruptive fissures starting at 0.24 Ma. The youngest lava flow, Roiho, is dated at 0.11 Ma. The Hanga O Teo embayment is interpreted to be a 200 m high landslide scarp.
Terevaka formed around 0.77 Ma of, tholeiitic to alkali basalts, followed by the collapse of its summit into a caldera. Then at about 0.3Ma, cinder cones formed along a NNE-SSW trend on the western rim, while porphyritic benmoreitic lava filled the caldera, and pahoehoe flowed towards the northern coast, forming lava tubes, and to the southeast. Lava domes and a vent complex formed in the Maunga Puka area, while breccias formed along the vents on the western portion of Rano Aroi crater. This volcano's southern and southeastern flanks are composed of younger flows consisting of basalt, alkali basalt, hawaiite, mugearite, and benmoreite from eruptive fissures starting at 0.24 Ma. The youngest lava flow Roiho, is dated at 0.11 Ma. The Hanga O Teo embayment is interpreted to be a 200 m high landslide scarp.