Hawaii Quakes in Hawaii could spell trouble for Kilauea Volcano By Margaret Myre / June 21, 2007 Share 1 -- Kilauea Volcano's Puu Oo cone, the conduit of nearly uninterrupted lava flows for more than two decades, stopped spattering this week when the magma stored 37 miles below the earth began to meander, setting off seismic tremors and threatening to end its fiery show forever. The series of more than 250 earthquakes that have shaken the ground and buildings in and around Hawaii Volcanoes National Park on the Big Island since June 17 have decreased in frequency to fewer than 10 an hour, but officials at the Big Island's biggest natural attraction have other problems on their minds, not the least of which are visitor safety and how much access visitors should have to the park.The tremors "appear to be settling down," said park ranger Mardi Lane. "There still remains some activity but on a much lower scale."That is to say, Kilauea isn't finished. The latest risk to visitors is toxic gas."Extremely high levels of sulfur dioxide" are venting from the volcano's Halemaumau crater and from three new fissures that opened up eight miles southeast of the crater, according to Jim Gale, chief of interpretation for the park. Halemaumau is a relatively small crater inside the massive Kilauea caldera. The fissures oozed lava for several hours on Tuesday and then began emitting volcanic acids.The Hawaiian Volcano Observatory reported on Wednesday concentrations of sulfur dioxide greater than 10 parts per million (ppm) in a broad area adjacent to Halemaumau. Anything higher is toxic, according to the International Volcanic Health Hazard Network. Park policy dictates that the Visitor's Center and Jaggar Museum close when concentrations exceed 1 ppm."Fortunately, we have good trade winds," Gale said, "so all the sulfur dioxide that's coming up from the magma below the Halemaumau crater is being blown away from the Visitor's Center and the Jaggar Museum."A smell like burnt matches fills the air, he said, and the dark sky above the normally glowing Puu Oo cone tells the story. The long-active vent, part of the tube system that brings magma from the Puu Oo crater to the surface in a fiery glow, started collapsing into itself as the crater floor began to fall. Reports Wednesday were that the deflation has stopped.Behind these manifestations is the shifting of the magma that lies beneath the ground, essentially draining the crater of the stuff lava is made of and denying visitors the view of a continuously erupting volcano.Whether the volcano, which has been erupting for more than 20 years, comes back to life, is uncertain, according to Gale. In a 1997 eruption, magma rose as steam, pressure was released, and, after a pause of 35 days, Kilauea erupted again."Everything indicates that the plumbing system for Kilauea volcano is alive and well," Gale said. "We don't know. We'll just have to wait and see."Rather than warding people off from visiting the park, the unusual seismic activity is attracting tourists and locals, Gale said."They still come because of this opportunity to see the most powerful forces on earth. To be here when this activity is going on is a great thing," he said. "We have rangers inside the park explaining what's going on."As of late Wednesday, much of the park remained open to visitors, including most of Crater Rim Drive, Mauna Loa Road and trails, the Kilauea Visitor Center, the Jaggar Museum, the Thurston Lava Tube, Namakanipaio Campground, the Volcano House hotel, Kilauea Military Camp and the Volcano Art Center Gallery.Closed, according to the park, are the southern portion of Crater Rim Drive from Jaggar Museum to Chain of Craters Road due to the "extraordinarily high concentrations of sulfur dioxide gas issuing from Kilauea's summit caldera;" Chain of Craters Road, which has been closed since Sunday; Hilina Pali Road; and the Halemaumau Trail, which closed Wednesday. Halemaumau Trail extends from the Volcano House hotel to the Halemaumau crater. Also closed are the park's eastern boundary in the Puna district near Kalapana; all east rift and coastal trails; and Puu Oo Trail.Kilauea is Hawaii's youngest volcano and one of the world's most active. More than 90% of Kilauea's surface is covered by lava less than 1,100 years old. In historical time, all of Kilauea's eruptions have occurred either in or near its summit caldera, or along the east or southwest rift zones.To contact reporter Margaret Myre, send e-mail email@example.com.