Geologists study volcanoes with balloons

Washington, August 15 : A team of geologists have taken meteorological balloons to the Kilauea volcano in Hawaii to make the first on-location measurements of volcanic gases as they actually spew from the mouth of the volcano.

The team of researchers, from the Michigan Technological University in the US, measured the temperature, composition and water content of the volcanic gases.

"The first flight was a success and made the first in situ measurements of gases in a volcanic plume using meteorological balloons," said Adam Durant from Michigan Tech.

In addition to seeing volcanoes up close, Durant and his colleagues wear goggles and breathing masks at the infernal mouth of the volcano.

He analyzed the plumes using controlled meteorological (CMET) balloons, which have altitude control and drift with winds.

"The balloons are piloted remotely by satellite link, with flight visualization using Google Earth. We were looking at tropospheric volcanic emissions of sulfur dioxide, carbon dioxide and water, which can be hazardous to human and animal health and degrade ecosystems," said Durant.

The scientists released two balloons in July that rode the winds in and out of the plumes emanating from Kilauea's Halema'uma'u crater.

Using instruments hanging below the balloon, the researchers measured the gases as the plumes rose up and away from the active volcano, one of three on Hawaii.

After the first balloon was released into strong winds left over from tropical storm Elida, it worked for a couple of hours, ascending to 2,500 meters around Mauna Loa mountain. The flight lasted for just under two hours before the balloon crashed into the mountain north of the launch site.

Durant and Watson spent the next three hours scouring the jungle on steep mountain slopes before finally locating the balloon, mostly intact.

The preliminary data is already interesting.

According to Durant, "We are fairly confident of three findings."

First, this work is feasible for measuring sulfur dioxide (SO2) and carbon dioxide (CO2) in volcanic emissions for several hours after eruptions.

Second, there is a loss of SO2 after one hour of flight away from the source, which could reflect conversion to sulfate aerosol (which may lower the Earth's temperature by reflecting away solar radiation).

And third, there is a clear stratification of SO2 above CO2 within the plumes.

"The stratification could represent separation of the gases through meteorological processes such as water droplet formation," said Durant.

This finding has implications for remote sensing studies that aim to measure volcanic gas emission rates.

ANI