Mauna Loa (United States): Recorded Eruptions and Historical Activity

Mauna Loa is an active shield volcano located in the United States at latitude 19.475 and longitude -155.608, reaching an elevation of 4,170 meters. Situated in an intraplate tectonic setting on oceanic crust less than 15 kilometers thick, Mauna Loa possesses a long and extensively documented record of volcanic activity maintained by the Smithsonian Global Volcanism Program.

According to the official record, Mauna Loa has 110 confirmed eruptions spanning from its earliest recorded eruption year of 8050 BCE up to its latest recorded eruption in 2022 CE. Across this entire collection, all 110 eruptions have documented Volcanic Explosivity Index (VEI) observations, with a largest recorded VEI of 2.0.

The historical record shows activity distributed across multiple centuries, shifting from prehistoric events dated through isotopic methods to historical events documented by direct human observations. For example, an early event on the Northeast rift zone (NE rift zone) is dated around 8050 BCE using uncalibrated carbon-14 isotopic evidence. Later historical milestones include an eruption spanning March 27, 1868, to April 22, 1868, which occurred across the southwest rift zone at 1,000 meters elevation and Mokuaweoweo with a recorded VEI of 2.0 based on reported observations. The most recent activity in the official record began on November 27, 2022, and ended on December 10, 2022, affecting Moku‘aweoweo and the Northeast Rift Zone.