FILE - In this Oct. 14, 2017, file photo, the sun rises over Hualalai volcano as male athletes start the swim portion of the Ironman World Championship Triathlon in Kailua-Kona, Hawaii. (AP Photo/Marco Garcia, File)
The Hawaiian Volcano Observatory, part of the U.S. Geological Survey, defines an active volcano as one that has erupted within the past 10,000 years.
Hawaii has five such volcanoes in addition to Kilauea, though Kilauea is the only one currently erupting.
Three are on the same island as Kilauea: Mauna Loa, Mauna Kea and Hualalai. One is on Maui: Haleakala. The last is Loihi, which is underwater to Kilauea's south.
