The volcano's crater covers a major portion of the park. Rising from the sea to 10,023 feet, the dormant volcano is one of the largest masses on earth. Deep valleys were carved by streams fed by tropical rains.
New lava flows filled in the valley floors, forming a new floor, with cinder cones up to 600 feet high. Two bare flows erupted low on the mountain's southwestern slope above La Perouse Bay in 1790.
