Lava Flows

Mauna Loa is the largest active volcano on Earth. Mauna Loa is in the shield-building stage of Hawaiian volcanism, a period when the volcanoes grow most rapidly, adding as much as 95 percent of their ultimate volume.

Mauna Loa had not erupted since 1984—its longest quiet period in recorded history.

The 1984 eruption of Mauna Loa ended a 9-year period of quiescence.

Following 25 years of slumber, Mauna Loa awoke with a spectacular, but short-lived, eruption just before midnight on July 5, 1975.

On June 1, 1950, a fissure erupted high on Mauna Loa's Southwest Rift Zone, and within 3 hours, ‘a‘ā lava flows had crossed the main highway on the west coast of the Island of Hawai‘i.

Mauna Loa's "secret" eruption began on April 26, 1942.

On November 21, 1935, an eruption began in Mauna Loa's summit caldera and quickly migrated down its Northeast Rift Zone.