On a human time scale, all but one of Hawaii’s volcanoes have long been extinct.Only Kilauea on Hawaii Island (or the Big Island) remains active, and continues to add new land to the island. The other four are dormant, however Mauna Loa last registered an eruption in 1984. But volcanism (the geologic kind, not the Star Trek kind) is how the world’s most isolated archipelago was formed and continues to grow.
Each of Hawaii’s major island is the very tip of a volcano that formed over a geologic hotspot that has been stationary for 40 million years. The tectonic plate that sits over the hotspot has been moving to the northwest over that time, forming volcanoes in Hawaii giving the islands their northwest-to-southeast orientation. Kauai, at the chain’s northeast, is the oldest, and the Big Island in the southeast is the oldest. Of all of the major Hawaiian Islands, the Big Island, Maui, and Oahu have volcanoes that have become synonymous with their islands.
There are five volcanoes on the Big Island, each the namesake of a geographic region. Mauna Kea (“white mountain”) is an extinct volcano that rises to over 13,000 feet, the highest point in Hawaii. At the summit is a cluster of high-powered telescopes peering into the heavens to reveal its secrets. Mauna Loa (“long mountain’) is a dormant volcano notable for its smooth surface. Hualalai’s last volcanic activity took place in 1929, evident in an intense cluster of earthquakes. This volcano remains potentially active, with an eruption expected by researchers in the next 100 years. The Kohala volcano last erupted at least 60,000 years ago. Once home to Hawaiian royalty, Kohala is now home to ranchers and resorts.
Kilauea Volcano, one of the most active on the planet, has been erupting continuously since 1983. Home to Hawaii Volcanoes National Park, Kilauea is responsible for the footage of explosive bursts and churning rivers of brilliant red lava. Kilauea continues to add to the island’s landmass, and it is still possible to see lava flowing in to the sea (with proper safety instruction, of course).
Haleakala (“House of the Sun”) on Maui is also home to several astronomical observatories. Visible on clear days from Oahu, Haleakala rises to 5,100 feet. Its crater is mostly barren and starkly beautiful. The slopes of Haleakalao, or “Upcountry Maui”, is home to ranches and farms. Activities at Haleakala include hiking, bike tours, agri-tours, and simply gawking at the sheer scale and beauty of this extinct volcano.
Oahu is home to three iconic volcanic craters. The most famous is, of course, Diamond Head. The subject of countless vacation and promotional photos, Diamond Head offers a well-maintained hiking trail to its summit, which offers a unique view of Oahu’s southern shore. Punchbowl Crater is home to the National Cemetery of the Pacific, the final resting place of many hundreds of American soldiers. Koko Crater, at Oahu’s southeastern tip is home to an increasingly popular hiking trail, a botanical garden, and a horse ranch.
Interestingly, even as Kilauea on the Big Island moves away from the hotspot, a new Hawaiian island is being born to its southeast. “Loihi” is in its infancy, but we can look forward to it rising above the ocean’s surface in about 50,000 years.