Article

01 October 2004

Mauna Loa volcano watch

Lava flowed from the summit of Manua Loa for only one day during the 5 July 1975 eruption. Mauna Kea looms in the background. Photograph courtesy of the Hawaiian Volcano Observatory of the United States Geological Survey.

Citizen scientists who reside on or who plan visits to the Big Island of Hawai'i may eventually witness the next eruption of Mauna Loa, the world's largest volcano.

Volcano eruptions are notoriously difficult or impossible to predict. Among the most important eruption precursors are swarms of small earthquakes. More powerful quakes may precede the eruption. Another signal of an impending eruption is a change in the tilt of the volcano.

Mauna Loa last erupted in 1984. A major lava flow reached the outskirts of Hilo on Hawai'i's northeast coast.

Based on the historical record, Mauna Loa is overdue for an eruption. Since July 2004, several hundred very deep earthquakes have been detected from various regions around the caldera and the slopes of the huge mountain. The width of the caldera has slightly widened, and the tilt of the mountain has slightly increased. These are signals that the volcanoes magma chamber could be inflating.

Forrest M. Mims III