Mauna Loa eruption could devastate area

Associated Press

VOLCANO, Hawai'i — Mauna Loa is stirring after an 18-year pause, and an eruption could be devastating to the neighborhoods built on the giant volcano's slopes in the intervening years, scientists said yesterday.

"There has been a substantial amount of development on what has historically been the most hazardous part of Mauna Loa — its southwest rift zone above South Point," said Peter Cervelli, a research geophysicist at the U.S. Geological Service's Hawaiian Volcano Observatory. "Though lava flows can reach Hilo on the eastern side of the island and the Gold Coast resorts of Kona in the west, flows are much more likely to inundate the subdivisions in the southwest rift zone — and possibly without much warning."

Mauna Loa has erupted 33 times since 1843. In spring 1984, Mauna Loa erupted for three weeks, sending a 16-mile lava flow toward Hilo. Since then, the USGS estimates that more than $2.3 billion has been invested in new construction along Mauna Loa's slopes, including the large Hawaiian Ocean View Estates subdivision on the southwest rift.

"When Mauna Loa erupts out of its southwest rift zone, it can get lava to the ocean in (a) matter of hours," Cervelli said. "It's remarkable that they chose to build there. In some cases they're building on lava flows that are less than 100 years old."

Scientists from Stanford University recently joined the observatory in monitoring the 13,500-foot volcano, which began to stir from sleep on May 12.

Recent geophysical data collected on the surface has revealed that Mauna Loa's summit caldera has begun to swell and stretch at a rate of 2 to 2 1/2 inches a year, which can be a precursor of an eruption, scientists said.

Scientists are working to detect an eruption as early as possible to give people a chance to evacuate the populated areas.

"Earthquakes will always precede the movement of magma to the surface," said Cervelli. "In our experience, it's going to be at least hours.

"It's not like Kilauea, where you just walk up to the lava and poke a stick in it," he said.

"Mauna Loa is capable of erupting huge volumes of lava in a relatively short period of time, and the flows can reach great distances," said Paul Segall, a professor of geophysics at Stanford who has worked with USGS volcanologists in Hawai'i since 1990. "It presents a more significant safety hazard than Kilauea."