Mauna Loa — The Biggest Active Volcano on Earth (Hawaii History + 2026 Status)
The Biggest Active Volcano on Earth
Mauna Loa does not look like a volcano. It looks like a gently sloping mountain that fills the entire southern horizon of the Big Island. Its flanks are so broad and its profile so low-angle that from most vantage points it is hard to understand you are looking at one of the most geologically significant features on the planet. Seen from space, it is a shield that covers more than half of the Big Island's land area. By volume — counting the ocean floor below it — it is the largest mountain on Earth.
Geological Context
Mauna Loa is a shield volcano, formed by repeated eruptions of low-viscosity basaltic lava that spread broadly rather than building steeply. It sits above a hot spot in the Pacific Plate — a plume of mantle material that has been punching through the seafloor and building islands for roughly 70 million years. The Hawaiian chain is the result: a string of increasingly older and more eroded islands stretching northwest from the Big Island all the way to the submerged seamounts at the chain's far end near Midway.
The Big Island is the youngest in the chain and the only one with active lava flows reaching the surface. Mauna Loa and Kīlauea are both above the hot spot; Lo'ihi, a submarine volcano about 22 miles southeast of the Big Island, is the newest volcano forming and will eventually emerge as the next Hawaiian island in tens of thousands of years.
Eruption History
Mauna Loa has erupted 33 times in recorded history since 1843, averaging roughly once every five years. The eruptions range from brief summit events to sustained rift zone eruptions that sent lava flows to the coast. Key historical events:
- 1868 — A major earthquake (estimated 7.9 magnitude) triggered lava flows and a landslide that killed 77 people — the deadliest natural disaster in Hawaiian history at the time.
- 1926 — Lava flow from the Southwest Rift Zone buried the village of Ho'opuloa on the Kona coast.
- 1935 and 1942 — The U.S. Army Air Corps bombed the upper lava flows to try to slow them before they reached Hilo. The effectiveness of the bombing remains debated.
- 1950 — One of the most spectacular eruptions in modern history. The Southwest Rift Zone sent lava 15 miles to the Pacific Ocean in just 3 hours. The volume of lava in the first 24 hours exceeded any other 20th century eruption at Mauna Loa.
- 1984 — Northeast Rift Zone eruption lasting 22 days. Lava flows threatened Hilo before stopping about 5 miles from the city's outskirts. The entire population of Hilo was watching the lava front advance.
- 2022 — The most recent eruption, November 27 to December 13. Lava fountains from the summit caldera and Northeast Rift Zone were visible from much of the island. No property damage, no injuries. The lava flow stopped about 2 miles from Saddle Road before the eruption ended.
Hawaiian Cultural Significance
Mauna Loa is not simply a geological feature to Native Hawaiians — it is a sacred place and an ancestor. The summit and the upper mountain are part of the sacred landscape that connects the Hawaiian people to their creation traditions. Pele, the volcano deity of Hawaiian tradition, is understood not as a metaphor but as a living presence in the volcanic activity itself. The eruptions are understood in cultural tradition as Pele's creative force, building land and expressing the power of the volcanic lineage.
The ongoing controversy over the Mauna Kea observatories (on the neighboring summit) has heightened awareness of the cultural dimensions of Hawaii's high mountains. Mauna Loa is within Hawaii Volcanoes National Park and managed in coordination with Hawaiian cultural practitioners.
2026 Status
Mauna Loa is not currently erupting. The USGS Hawaiian Volcano Observatory monitors the volcano continuously via seismic sensors, GPS deformation measurements, and gas emission monitoring. Current alert levels and daily updates are published at volcanoes.usgs.gov/hvo. Given the historical average of roughly one eruption every five years and the 2022 eruption, the volcano remains closely watched.
Visiting Mauna Loa
The accessible viewpoint is the Mauna Loa Lookout at the end of Mauna Loa Road (off Route 11 inside Hawaii Volcanoes National Park) — paved to 6,662 feet, accessible to any vehicle, no permit required beyond the park entrance fee. For the 2022 Northeast Rift Zone flow, Saddle Road (Route 200) provides views of the fresh lava from the road. The summit trail is a two-plus day technical hike requiring permits and cold-weather gear.
**Mauna Loa is the largest active volcano on Earth.** Not the tallest — Mauna Kea next door beats it by about 100 feet — but by sheer volume of rock, Mauna Loa is unmatched. It's 60 miles long, 30 miles wide, covers half the Big Island, and rises 13,679 ft above sea level.Looking for things to do in Hawaii? Browse upcoming events →
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