Saturday, January 07, 2006

Changes noticed about Mauna Loa volcano

Earthquakes at Mauna Loa sharply declined during 2005, leading geophysicists to believe the world's largest volcano is less likely to erupt than they earlier thought.

Scientists recorded about 2,000 earthquakes at Mauna Loa on the Big Island in 2004. Many of the temblors were deep, long-period events suggesting magma was rising.

But the seismic activity backed off at the beginning of last year. Last January, scientists recorded 34 earthquakes, a sharp decline from 365 the previous month.

"Last December (2004), most people were predicting an eruption soon. The story 12 months later is completely different," said geophysicist Mike Poland of the Hawaiian Volcano Observatory. "Relative to last year, I'd say we are further from an eruption."

The 13,677-foot high volcano has erupted 33 times since its first well-documented event in 1843. In 1984, lava from the eruption came within four miles of Hilo.

Another eruption could devastate nearby communities.

"We're kind of worried. We live right by a big rift that's been active before and it can happen again," said Ken Wicks of Hawaiian Ocean View Estates, a rural subdivision on the southwest side of the Big Island. The area could be in the path of lava from an eruption in Mauna Loa's southwest rift zone.

"It's always in the back of our mind. We never forget it. It is a reality," said Wicks, who is president of the Ocean View Chamber of Commerce.

The observatory last year boosted its ability to monitor the mountain when it installed instruments at the summit to record the sulfur dioxide and carbon dioxide concentrations in vapors the volcano emitted.

The equipment transmits the data to the observatory every 10 minutes. Before, the lab had to fly helicopters over the mountain every few months to obtain the same information.

The facility also placed a panoramic camera at the summit to help it verify reports of eruptions and other substantial changes at the volcano's crater.

"We're always looking for ways to determine when magma is going to go out into a rift zone," said Jim Kauahikaua, the observatory's scientist-in-charge.

Mauna Loa's neighbor, Kilauea, continued to be very active in 2005, spewing out an average of 500,000 cubic yards of lava per day.

Lava flows from Kilauea have consumed 189 buildings and added about 600 acres to the Big Island since 1983.

Both Mauna Loa and Kilauea are part of Hawaii Volcanoes National Park.

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