Volcano Chasers at Mt. Etna

July 28, 2001 -- Europe's most active volcano, Mount Etna, has been gushing lava for two weeks and today forced the airport in Sicily to close. But for volcano trackers it was a perfect time for a trek up the mountain.

In the past 24 hours, Mount Etna has been at its best. Scientists say it is as active as it was when it first erupted. The Italian military continued its fight to keep the lava away from Etna's ski resort. It is an amazing volcano and scientists say it could be a gold mine.

Borris Behnke is a German scientist, an expert on volcanoes. But out here he is like a child.

Today, Behnke led this team of amateur volcano watchers to Mt. Etna's most explosive craters.

Just how big are the boulders coming out of the mountain?

"Well surely some of them are bigger than cars, and some might be as big as trucks," said Behnke.

As spectacular as this crater looks during the day, at night it is almost beyond description. For those who study volcanoes, walking up the mountain is an essential trip. Dozens of volcanologists from all parts of the world climb this mountain everyday. This eruption, Behnke says, will be the most studied of all time.

"It will probably make us learn more about the dynamics of Etna and about the storage and transport of magma in the volcano than we've had before," said Behnke. "We will probably learn more about this volcano during this eruption than had been learned in 3,000 years."

One reason — hundreds of monitoring devices planted around the volcano send a constant stream of data to scientists a few miles away. They analyze the gases coming from the craters. They track the flow of lava and measure seismic activity. In the days leading up to this eruption there were more than 2,600 small earthquakes centered on the volcano. Even for Etna, that is remarkable.

Behnke said this is a complicated eruption becuase the lava is shooting out from so many places on all sides of the volcano. For scientists a complex eruption is a gold mine.

"I guess we'll be getting plenty of information about the plumbing system of the volcano, the places where magma is being stored," Behnke said. "For this we need to take rock samples."

Behnke said he will climb this mountain many times this year. The volcano, he believes will keep blasting for at least six more months.

ABCNEWS' Bob Woodruff contributed to this report.