Although it is the most active volcano on earth, many visitors to Hawaii Volcanoes National Park standing on the very summit of Kilauea Volcano often stare and wonder: “Where’s the volcano?” Nestled snugly up against Mauna Loa, and not as vertically spectacular as either this near neighbor or Mauna Kea, Kilauea doesn’t even appear to be a bump on the landscape from the usual viewpoints. Even though it doesn’t standout visually, Kilauea is one of the most intriguing and fascinating volcanoes on earth ... let’s just take a quick look at some of the reasons why.
Comprising the entire southeastern portion of Hawaii Island, Kilauea Volcano is not only currently the world’s most active volcano—it is also the home of the fire goddess Pele. Early geologists believed Kilauea was merely a satellite vent of Mauna Loa, as it lies directly on that mountain’s southern slopes. However, Kilauea is now recognized as its own distinct volcano that has its own separate magma source, and unique plumbing.
Presenting the classic Hawaiian “shield volcano” shape, a basic oval with low, shallow slope angles, volumewise Kilauea is one of the world’s most massive mountains. Standing 1240 meters (4080) above sea level, the above-ocean part of the volcano is about 80 km (50 miles) long and 32 km, (20 miles) wide, along an axis trending roughly southwest to northeast. However, like all the other Hawaiian volcanoes, the great majority of its vast bulk lies below the sea, about 5.5 km (18,000 feet) deep here, making Kilauea’s true base-to-summit height about 7 km (23,000 ft).
Sometimes vying with Mts. Aetna and Stromboli for the title of “most active volcano on earth,” Kilauea has been erupting continuously since January 1983; between then and June 2009, nearly 700 acres of new land was created on Hawaii Island by Kilauea lava flows. As the time scale of human lives and human tragedy are so much shorter than geologic time scales, and thus human memories of past disasters grow dim rather rapidly, this volcanic growth has come at quite a cost because people insist on building villages, towns, and roads on this highly active landscape. In recent decades, the towns of Kapoho (in 1960), Kalapana (in 1990), and Kaimu (in 1990) have all been burned, buried and destroyed by Kilauea, and now are seemingly all but abandoned except by a few hardy souls. Although popularly thought to be rather tame with fairly peaceable eruptions, Kilauea in the past has had its fair share of explosive, violent, phreatomagmatic eruptions, spewing great quantities of ash as well.
Kilauea owes its peculiar shape to two long rift systems, the currently active East Rift and the Southwest Rift. These rifts are comprised of huge, deep fractures through the bulk of the mountain. Magma rises from deep below the volcano to a pool just below the summit caldera, then flows through internal plumbing down either rift, causing flank eruptions at vents downrift. These flank eruptions greatly enhance Kilauea’s exaggerated elongate shape. In recent times, many more eruptions have occurred along the East Rift, than the Southwest Rift.
