Volcano Watch — Where will the next Hawaiian volcano appear?

As we all know, there are no facts about the future. We cannot know for sure what will happen tomorrow, much less next year or 1,000 years from now. How, then, can we be so bold as to guess where the next volcano will form in Hawai`i, perhaps 100,000 years or more down the road?

If volcanoes were scattered randomly throughout the Hawaiian Islands, no one could say where the next volcano might start erupting. It would be like trying to guess the winning number in the lottery. Once in a while someone gets lucky, but most of us lose.

But volcanoes in Hawai`i are not lottery numbers. They occur in a remarkably systematic arrangement, and we have learned enough about this pattern to make a pretty good guess as to where the next volcano will form. For starters, the volcanoes get younger toward the southeast end of the island chain. The first Polynesians to settle in the islands recognized this, 19th-century naturalists confirmed it, and late 20th-century earth scientists found a reason for this pattern.

The thin Pacific plate of the earth's crust moves northwestward about 13 cm (5 inches) a year. The plate rides over a hot spot or plume that causes rock below the crust to melt and slowly float toward the surface. Some of the melted rock, called magma, erupts to form a volcano on the Pacific plate. The volcano is carried away from the hot spot as the plate continues to move northwestward. The volcano eventually loses contact with the hot spot and dies. Another volcano takes its place over the hot spot, and the beat goes on--always birth to the southeast and death to the northwest.

Not only do the volcanoes get younger toward the southeast, but they are spaced about the same distance apart and occur on one of two gently curving lines. If you don't believe it, get out a map. Starting from O`ahu, you will see that one line of volcanoes includes Wai`anae, Ko`olau, West Moloka`i, Lana`i, Kaho`olawe, the submerged volcano of Mahukona, Hualālai, Mauna Loa, and Lo`ihi. The summits of these volcanoes are spaced about 40-60 km (25-40 miles) apart.

Another parallel line a little farther east includes East Moloka`i, West Maui, East Maui (Haleakalā), Kohala, Mauna Kea, and Kīlauea. These volcanoes are also about 40-60 km (25-40 miles) apart, except for a gap between Haleakalā and Kohala in which another small volcano may have formed but is now obscured. These two lines were first recognized in the 19th century by the famed naturalist James Dana, who named them the Loa (from Mauna Loa) and Kea (from Mauna Kea) lines, respectively.

Lo`ihi is at the southeastern end of the Loa line. It is in the process of taking over from Mauna Loa, which some evidence suggests may already be in a state of slow decline. Kīlauea is at the end of the Kea line and is obviously still full of vigor. But eventually it will be replaced by the next Hawaiian volcano, which, judging from the spacing up the chain, will be centered some 40-60 km (25-40 miles) southeast of Kīlauea. It will become Lo`ihi's rival, much as Kīlauea is today the rival of Mauna Loa.

Former HVO directors Jim Moore and Dave Clague feel so confident about the location of the next volcano that they have already named it: Keikikea, "child of Kea." The birth of Keikikea is probably still in the future a few tens of thousands of years or more, though, so don't hold your breath.

Volcano Activity Update

There were no changes in the activity of the east rift zone eruption of Kīlauea Volcano from the vent at Pu`u `O`o. Lava continued to flow through a network of tubes down to the seacoast where it entered the ocean at two locations - Waha`ula and Kamokuna. The public is reminded that the ocean entry areas are extremely hazardous, with explosions accompanying frequent collapses of the lava delta. The steam cloud is highly acidic and laced with glass particles.

There were no earthquakes reported felt during the past week.