Aerial view of lava delta (center, left of volcanic fume) growing seaward at Kamoamoa on Kilauea Volcano, Hawai`i.
A lava delta is formed by lava entering the sea and building a wide, fan-shaped area of new land. Such new land is usually built on sloping layers of loose lava fragments and flows. On steep submarine slopes, these layers of debris are unstable and often lead to the sudden collapse of lava deltas into the sea.[1]