Volcano’s white gas tells staff it’s not ash

HILO » Halemaumau's brown plume turned white yesterday morning, indicating that ash was no longer part of the mix, the Hawaiian Volcano Observatory said.

By yesterday afternoon the plume of toxic gas was alternating from brown to white and back, the observatory said.

The plume of water vapor and sulfur dioxide gas mixed with air started out white when it began March 12.

When it turned brown Sunday, scientists decided the reason was the gas stream was picking up tiny particles of broken rock inside the conduit, or rock pipe, that leads to the surface, the observatory said.

While the ash content varied yesterday, the sulfur dioxide continued at about 1,500 metric tons a day, down from a high of 2,500 metric tons but still nearly 10 times above last year's average.

None of the gas was reaching populated areas, but a new venting sound could be heard, contrasting with the previously quiet emission of gasses.

The increased activity is drawing more visitors. Nearly 9,000 people a day are touring Hawaii Volcanoes National Park on average so far this year, a 2.5 percent increase over last year when the volcano's 25-year eruption was much more peaceful, said Cindy Orlando, the park's superintendent.