(AP) SEATTLE – The new lava lobe inside Mount St. Helens’ crater has sprouted a piston-like protrusion the size of a 30-story building — glowing red at night.
“The magma is pushing the plug upward. It’s going high in the sky,” said hydrologist Carolyn Driedger of the U.S. Geological Survey at the Cascades Volcano Observatory in Vancouver, about 50 miles from the southwestern Washington mountain.
One section of the new lobe has risen by 330 feet in the past nine days, Driedger said Friday. Exact dimensions are not yet known but will be determined from photos taken Thursday.
“It seems like every time you think you know what’s going on, (the volcano) twists and does something different,” said Jeff Wynn, chief scientist for volcano hazards at the observatory.
Two scientists flew into the crater by helicopter Thursday and landed beside the new structure, under strict orders to stay no longer than 10 minutes to collect samples, he said.
The new lobe, which began building last month, had grown to roughly the size of an aircraft carrier. Scientists described it as 900 feet long and 250 feet wide.
Magma, or molten rock, is reaching the surface at the rate of 7 to 8 cubic meters about one large dump truck load — every second, Wynn said.
Like the old lava dome, formed in the six years after St. Helens’ devastating May 18, 1980, eruption, the new lobe is made of a type of volcanic rock called dacite, Wynn said. More than 63 percent silica, it tends to be sticky and viscous, unlike the free-flowing lava of Hawaii.
Temperatures on the new protrusion can spike as high as 1,200 degrees Fahrenheit.
The volcano rumbled back to life Sept. 23, with shuddering seismic activity that peaked above magnitude 3 as hot magma broke through rocks in its path. Molten rock first reached the surface Oct. 11, marking the resumption of dome-building activity that had stopped in 1986.
A more explosive eruption, possibly dropping ash within a 10-mile radius of the crater, is possible at any time, scientists have said.