Largest Active volcano - Mauna Loa in Hawaii has a dome 75 miles long and 64 miles wide, with a lava flow that occupies more than 2,000 square miles of the island. Its pit crater, Mokuaweoweo, measures 4 square miles and is 500-600 ft deep. It rises 13,677 ft and has averaged one eruption every 3 1/2 years since 1832, although none since 1984. (Photo: Peter Menzell/Science Photo Library)
