Hualalai is the westernmost shield volcano on the Island of Hawaii. Three rifts radiate to the north, south, and northwest. The shield-building stage was completed by 120,000 years ago. About 105,000 years ago a trachyte cone, Puu Waawaa, formed on the north rift and generated flows that traveled about 6 miles (10 km). Post-shield volcanism began 100,000 years ago and covered the entire surface of the volcano.
The most recent eruptions of Hualalai occurred in 1800-1801. Two large flows reached the ocean. The Kona airport is built on the 1801 flow. This view of the volcano is to the southeast and shows the 1800-1801 lava flows. The long slope of the flank of Mauna Loa volcano is in the background.
More information on Hualalai from the Hawaii Volcano Observatory!