Posted on: Friday, March 7, 2003

Mauna Loa gives signs of swelling

By Kevin Dayton
Advertiser Big Island Bureau

HILO, Hawai'i — There are signs things are picking up again under Mauna Loa, although scientists studying the 13,680-foot volcano said they need more data before they can be sure.

After about two months of relative quiet, sensitive global positioning system instruments once again appear to be picking up an inflating of the Mauna Loa caldera called Moku'aweoweo, indicating swelling of the magma reservoir below.

Similar swelling was observed before the last two eruptions at Mauna Loa, but Peter Cervelli, research geophysicist for the Hawaiian Volcano Observatory, said the apparent uptick in underground activity is no cause for alarm.

Scientists still can't say for sure the swelling has resumed, he said.

Unmistakable swelling of the Mauna Loa caldera began in late April or May and continued for about five months before slowing in late October or November. The swelling appears to have resumed in early February.

Cervelli cautioned that the recent changes are being recorded by instruments that weren't available during previous eruptions.

"It may be that we're in store for all kinds of wiggles and bumps and grinds, and that we're just going to have to get used to them," he said.

Mauna Loa's longest period without an eruption was 25 years, from 1950 to 1975. The volcano last erupted19 years ago, in March 1984.