Mauna Loa (mou`nə lō`ə), mountain, 13,680 ft (4,170 m) high, in the south central part of the island of Hawaii, in Hawaii Volcanoes National Park Hawaii Volcanoes National Park, 209,695 acres (84,926 hectares), on Hawaii island, Hawaii; est. 1916. The park contains two of the most active volcanoes in the world— Kilauea with its fire pit, called Halemaumau, and Mauna Loa with the active Mokuaweoweo crater
..... Click the link for more information. . Its many craters include Kilauea and Mokuaweoweo, two of the world's largest active craters. Mauna Loa has erupted three times (1942, 1949, 1975) since its period of greatest activity in 1881. Its lava flows have reached the sea.

Mauna Loa

Volcano, south-central Hawaii island, Hawaii, U.S. Located in Hawaii Volcanoes National Park, it is one of the world's largest mountain masses. It rises to 13,678 ft (4,169 m) and has a dome 75 mi (120 km) long and 64 mi (103 km) wide. Mokuaweoweo, its pit crater, has an area of nearly 4 sq mi (10 sq km) and a depth of 500–600 ft (150–180 m). It has averaged one eruption every 3.5 years since 1832. Many of its eruptions are confined within Mokuaweoweo; others are from fissures and vents. Its lava flows occupy more than 2,000 sq mi (5,120 sq km) of the island. See also Kilauea.