How did Mauna Loa volcano form?

Volcanoes on the Big Island with Mauna Loa highlighted, Mauna Loa, or "Long Mountain" in Hawaiian, is located on the island of Hawaii. It is pictured above rising 13,680 ft. (4,170 m) above sea level (this photo was taken from over Loihi seamount, some 30 km or so to the south). read more

Mauna Loa is an active shield volcano, with lava consisting primarily of highly fluid basalt. To attain its present size, the volcano went through several cycles of eruptive activity at its summit, followed by activity in the lower rift zones. read more

Mauna Loa and the other Big Island volcanoes were formed by a mantle plume sometimes called a hot spot, underneath the middle of the Pacific Plate. A mantle plume is an upwelling of abnormally hot rock within the Earth's mantle. read more

Following the invention of modern monitoring equipment, the backbone of the present-day monitoring system was installed on the volcano in the 1970s. Mauna Loa's July 1975 eruption was forewarned by more than a year of seismic unrest, with the HVO issuing warnings to the general public from late 1974; the 1984 eruption was similarly preceded by as much as three years of unusually high seismic activity, with volcanologists predicting an eruption within two years in 1983. read more

A: Lava eruptions, from a plume of magma known as the Hawaiian hot spot, began the formation of Hawaii's Mauna Loa 600,000 to 1 million years ago. This plume of magma is responsible for the formation of the entire chain of Hawaiian islands. read more

Mauna Loa (/ˌmɔːnə ˈloʊ.ə/ or /ˌmaʊnə ˈloʊ.ə/; Hawaiian:; English: Long Mountain) is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean. The largest subaerial volcano in both mass and volume, Mauna Loa has historically been considered the largest volcano on Earth. read more