Hualalai

The basaltic Hualalai, at the western end of the island, is the third youngest shield volcano on Hawaii. Three rift zones, with numerous cinder cones and spatter cones, trend N, NW, and SE, and converge about 5 km E of the summit. Detailed mapping has shown that 95% of the surface area is of Holocene age, more than half is less than 3,000 years old, and a quarter is less than 1,000 years old.

Eruptions at the end of the 18th century and in 1801 produced lava flows from vents on the NW rift zone that reached the sea and buried villages; the 1801 Huehue lava flow underlies part of the airport at Kona. The earlier of the two flows, the Kaupulehu lava flow, is notable for its large quantities of lava-encrusted mafic and ultramafic nodular xenoliths.