U.S. Geological Survey - Hawaiian Volcano Observatory

Mauna Loa - Current Activity - Hazards

Eruption History

Mauna Loa has grown rapidly during its relatively short (600,000 to 1,000,000 years) history to become the largest volcano on Earth. Although its rate of growth appears to have slowed in the past 100,000 years, our detailed geologic research on the volcano has nevertheless shown that about 98 percent of the volcano's surface is covered with lava flows less than 10,000 years old! Based on reliable ages of nearly 200 of these flows, we've found that Mauna Loa has erupted in time and place in fundamentally different ways -- as eruptions from the summit of Mauna Loa become larger and more frequent, eruptions from the rift zones decline.

A cyclic model was recently proposed for the volcano's summit-flank alternation of eruptive activity. Detailed geologic mapping suggests that the cycles may last about 2,000 years each. Since the most recent period of intense summit activity began about 2,000 years ago, perhaps Mauna Loa is "on the verge of shifting to a period of long-lived lava-lake activity, shield-building, increased summit overflow, and diminished rift zone eruptions." See a technical summary of this proposed cyclic model.

Summary of Historical Eruptions (table)

Narrative of the 1984 Eruption

The 1950 Southwest Rift Zone Eruption

Reference

Lockwood, J. P., 1995, Mauna Loa eruptive history - the preliminary radiocarbon record, Hawai`i, in Rhodes, J.M., and Lockwood, J. P. (eds.), Mauna Loa revealed: structure, composition, history, and hazards: Washington D.C., American Geophysical Union Monograph 92, p. 81-94.