In what year did Mauna Loa last erupt?

Mauna Loa last erupted in 2022. The eruption began on November 27, 2022, inside the volcano’s summit caldera on Hawaiʻi Island, then shifted to vents along the Northeast Rift Zone. It ended on December 10 after more than two weeks of lava fountains and flows.

The event was significant because it was Mauna Loa’s first eruption since 1984, ending a 38-year quiet period—the longest in its recorded history. Mauna Loa is a shield volcano, so its eruptions usually produce extensive, relatively fluid lava flows rather than the towering explosive columns associated with some stratovolcanoes.

The 2022 lava approached Saddle Road and briefly disrupted access and power at the Mauna Loa Observatory, but no injuries or deaths were recorded. A common mix-up is confusing Mauna Loa with nearby Kīlauea, whose 2018 eruption caused major destruction. Mauna Loa and Kīlauea are separate volcanoes, although both are on Hawaiʻi Island.