The Hawaiian Islands owe their existence to a fixed plume of heat deep within the Earth’s mantle, a geological feature known as a hotspot. As the Pacific tectonic plate slowly drifts over this persistent source of magma, it creates a chain of islands, each capped by colossal shield volcanoes. This process ensures that volcanism is a defining, continuing force in the islands’ formation and landscape. Understanding the most recent activity requires looking at major events that conclude a cycle of magma movement, as well as the sustained activity that characterizes the region.
The 2022 Mauna Loa Eruption
The most recent major eruption to begin and conclude on the Island of Hawaiʻi occurred at Mauna Loa, the world’s largest active volcano. This event began on November 27, 2022, ending the volcano’s longest quiet period in recorded history, which had lasted 38 years since 1984. The eruption initially started within Mokuʻāweoweo, the summit caldera, with lava flows covering the floor.
The activity quickly migrated out of the summit within hours, shifting to the Northeast Rift Zone as fissures opened at high elevations. Lava fountains, characteristic of Hawaiian-style eruptions, fed substantial flows that moved down the northern flank. The eruption focused on Fissure 3, which produced the main flows traveling toward the Daniel K. Inouye Highway (Saddle Road).
Scientists estimated that between 200 and 250 million cubic meters of lava were extruded during the first 12 days, a high volume highlighting the event’s magnitude. The lava flows extended 12 miles from the vents, stopping approximately 1.7 miles from the major cross-island roadway. The eruption officially ceased when the lava supply to the Fissure 3 vent cut off, and the Hawaiian Volcano Observatory confirmed the end of activity on December 10, 2022.
Why Defining “Last Eruption” Is Nuanced
While the Mauna Loa event of 2022 was the last major eruption with a distinct start and end date, defining the “last” eruption is complex due to the nature of activity at the neighboring Kīlauea volcano. Kīlauea is one of the most active volcanoes globally and frequently demonstrates sustained, long-term eruptive periods rather than singular events. The period surrounding the Mauna Loa eruption provides a clear example of this challenge.
Kīlauea had an eruption ongoing within its summit crater, Halemaʻumaʻu, active since September 2021. This activity temporarily paused around December 12, 2022, almost simultaneously with the conclusion of Mauna Loa’s eruption. The pause was brief, and Kīlauea resumed activity in the Halemaʻumaʻu crater on January 5, 2023, initiating a new phase of continuous, contained lava lake activity.
The distinction lies in the type of event. Mauna Loa’s 2022 eruption was a new, high-volume release of magma from a volcano quiet for decades, which subsequently concluded. Kīlauea’s activity, though sometimes pausing and restarting, is often treated as an extended episode of sustained magma output contained within the summit caldera. Therefore, Mauna Loa was the last major event to conclude, but Kīlauea often holds the record for the most recent instance of lava at the surface.
Status of Hawaii’s Other Active Volcanoes
Beyond Mauna Loa and Kīlauea, several other volcanic centers contribute to the Hawaiian chain, each with a distinct status. Kīlauea remains at a heightened state of activity, characterized by episodic lava fountaining and effusive flows typically confined to the deep Halemaʻumaʻu crater. Its high frequency of activity makes it the subject of nearly continuous monitoring by the Hawaiian Volcano Observatory.
Hualālai, the third most active volcano on the Island of Hawaiʻi, is considered seismically active despite its long quiet period. Its last surface eruption occurred in 1801, and geological mapping suggests it erupts approximately two to three times every 1,000 years. Although inactive for over two centuries, scientists anticipate a future eruption within the next 100 years, making monitoring a priority due to the populated areas on its flanks.
Mauna Kea, the tallest mountain in the state when measured from its base on the ocean floor, is considered dormant. Its last eruption occurred more than 4,000 years ago, and it exhibits low levels of seismic activity. The volcano is at a normal alert level, reflecting its stable, inactive state.
The youngest volcano in the chain is Kamaʻehuakanaloa, formerly known as Lōʻihi Seamount, which is entirely submarine. Its summit is nearly 1,000 meters below sea level, and it is in the earliest stage of its life, expected to breach the ocean surface tens of thousands of years from now. The most recent significant activity detected was a major earthquake swarm in 1996, indicating magma movement deep below the ocean floor.