Visiting Mauna Loa, the Largest Volcano in the World

If visiting the world's largest volcano sounds dangerous, think again: not all volcanoes erupt with abandon and leave towns covered in molten lava and ash.

While it's certainly true that volcanoes like Mount Tambora in Indonesia (on record as the world's deadliest) and Mount Vesuvius in Italy (one of the most active volcanoes in the world) do indeed pose threats, many volcanoes are far less dramatic. Such is the case with Hawaii's Mauna Loa, which happens to be the world's largest active volcano, by both volume as well as size.

After being dormant since 1984, Mauna Loa began to show signs of seismic activity in October 2022 and erupted for the first time in 38 years at 11:30 p.m. on Sunday, Nov. 27. While the volcano's remote location inside Hawaii Volcanoes National Park means there is no immediate danger to local residents, there have been some in-park road closures as a result of the eruption. Several hiking trails and cabins have also been closed since October 2022 as a precaution.

Nevertheless, it's still safe to visit Hawaii and its beloved Big Island, though you'll want to keep an eye on the U.S. Geological Survey's website if you wish to catch a glimpse of the new lava flows. Hawaii Volcanoes National Park remains open as well — remember to check for updates before you go, as conditions can change rapidly.

Head to Hawaii

Mauna Loa is located on the Big Island of Hawaii, which is the largest island in the archipelago itself. In the Hawaiian language, its name means "long mountain," and along with four other volcanoes — Mauna Kea (the tallest volcano on Earth, home to many telescopes and observatories), Kilauea (the one you've likely seen photos of, with its frequent and powerful eruptions), Hualalai and Kohala — it forms the very structure of the island.

Mauna Loa is considered to be a shield volcano, meaning it was created by the flow of lava over time. Such volcanoes are not particularly tall (at least in the world of volcanoes). Instead, they grow wide like shields (hence the name). When measured, Mauna Loa's lava tallies more than 56,000 feet, though its actual elevation is only 13,680 feet.

It's theorized that the islands of Hawaii began forming 30 million years ago, beginning when the first volcanoes erupted through the ocean floor. Geologists estimate that Mauna Loa has been erupting for over 600,000 years and peaked its head above water just 300,000 years ago. Today, Mauna Loa continues to expel lava, thus adding to the acreage of this ever-expanding island.

Don't Worry About Explosions

But what can be said of Mauna Loa's explosions? While the volcano's history of volcanic eruptions has only been recorded since 1843, geologic evidence of other explosive eruptions over the past 1,000 years had suggested another one was possible. Its most recent eruptions tend to be in the form of fluid lava flows — during the previous eruption in 1984, the lava flow emerged from the summit and headed downslope toward Hilo, the island's largest city. While it missed the city limits by roughly four miles, the lava was so bright it illuminated Hilo at night.

So far, the lava from the November 2022 eruption is located within the Northeast Rift Zone. Authorities warn that bits of volcanic glass, fine ash, and a natural phenomenon known as "Pele's hair" — thin volcanic glass fibers named for the legendary Hawaiian volcano goddess — may be carried downwind. Since it's a shield volcano, you won't be seeing dramatic movie-like explosions, but lava appearing through fissures and flowing downhill is still an impressive sight when viewed from a safe distance, like a lookout point on nearby Kilauea, also part of the national park.

Visit Hawaii Volcanoes National Park

Mauna Loa continues to be an extremely popular tourist destination, attracting over one million visitors each year to Hawaii Volcanoes National Park. Come to the park to walk through lava tubes, enjoy more than 150 miles of hiking trails, and watch a volcano or two erupt — Mauna Loa and its neighboring shield volcano, Kilauea, are both currently active (Kilauea since Sept. 29, 2021). Check the website for the latest updates — and information on the best eruption viewing spots within the national park.

Mauna Loa also holds the distinction of being part of a volcano club, of sorts. The International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) included Mauna Loa in a group of 16 volcanoes known as "Decade Volcanoes," which earned this moniker simply because they were announced during the "International Decade for Natural Disaster Reduction," part of a global project in the 1990s that was sponsored by the United Nations. (They're not called "Decade Volcanoes" because they erupt every decade.) These 16 volcanoes continue to be of particular interest because of their high levels of activity as well as their proximity to large population centers. Washington's Mount Rainier and Sicily's Mount Etna also made the list.

Perhaps most interestingly, Mauna Loa has some competition for the crown of the largest volcano — that is, on the Earth's surface. Roughly 1,000 miles east of Japan is an extinct volcano dubbed Tamu Massif, which lies underwater. Its discovery was only announced in 2013, however in 2019, researchers found that Tamu Massif may actually be a part of a volcanic chain, rather than a single volcano, which meant giving Mauna Loa its title back.

As for the tallest volcano on Earth, neighboring Mauna Kea, a dormant volcano also located on the Big Island of Hawaii, stands just a couple hundred feet higher, surpassing Everest by almost a mile if you consider how much of the volcano is submerged below sea level.