SEATTLE – The new lobe on the lava dome in Mount St. Helens’ crater has grown to roughly the size of an aircraft carrier.

After getting a good look into the crater, U.S. Geological Survey scientists said the new feature is about 900 feet long, 250 feet wide and 230 feet high.

“That sucker is huge,” said Jeff Wynn, chief scientist for volcano hazards at the Cascades Volcano Observatory in Vancouver, about 50 miles from the southwest Washington mountain.

It’s still growing, he said Thursday, and glows red-hot at night.

Seismic activity is diminishing and “does not seem to correlate with how much material is coming out,” Wynn said.

Earthquakes at the volcano are well below magnitude 1 and occurring at a rate of three or four per minute, said Bill Steele at the University of Washington seismology lab in Seattle. That’s been the pace for about three days.

USGS scientists managed to collect some rock samples from the new lava lobe on Wednesday, using a bucket dangled from a helicopter on a 100-foot line.

“No one is allowed to walk in there,” Wynn said. Trails within a five-mile radius remain closed, as does the Johnston Ridge Observatory, five miles north of the 8,364-foot mountain.