St. Helens comes aglow

Wednesday, October 13, 2004
By ERIK ROBINSON, Columbian staff writer

MOUNT ST. HELENS - Fire-red lava emerged from the steaming crater of Mount St. Helens with a minimum of fuss Tuesday, but scientists cautioned that a bigger explosion may be yet to come.

    The volcano continued spewing a near-constant plume of steam.

    Lava appeared at sunset Tuesday, creating an eerie glow of hot rock and gases reflecting off steam. Scientists roughly estimated the fin-shaped slug of lava to be about 20 yards high and 40 yards long. It poked from the center of a massive uplift of glacial ice and rock between the south wall of the crater and a pre-existing lava dome.

    The old 876-foot-tall dome oozed up from the crater floor in a series of eruptions between 1980 and 1986, so the new lava marks the first extrusion in 18 years.

    "It was just a matter of time," said Tina Neal, a scientist with the U.S. Geological Survey.

    The uplift, which occurred over the past week and a half, has drawn intense scrutiny from scientists who are accumulating a growing array of equipment capable of monitoring the restless volcano from afar. On Tuesday, they unveiled a remote-controlled aircraft, with an 8-foot wingspan, capable of flying monitoring gear into hazardous airspace.

    The drone will be used to watch development of the new dome.

    Scientists had for days focused on the swelling mound of rock and glacial ice, waiting for the lava that emerged Tuesday night. Using thermal imaging technology, scientists on Tuesday morning determined the extrusion to be 1,100 degrees Fahrenheit about 450 degrees below the point where liquid lava begins cooling into solid rock.

    So far, lava appears to be arriving without posing a threat.

    "Right now, it just seems to be moving along rather happily," said Willie Scott, a geologist with the U.S. Geological Survey in Vancouver.

    Scott identified an aerial image taken by a Columbian photographer at 6:50 p.m. Tuesday as extremely hot rock, but probably not so hot to be in liquid form. The photograph shows the area of uplift where scientists identified the extrusion earlier in the day.

    "It's hot enough to be incandescent," he said.

    Although scientists expect nothing close to an eruption of the size that obliterated 1,300 feet of the volcano's once-symmetrical peak on May 18, 1980, they said gas-charged magma deeper within the mountain's piping system may yet emerge in a larger explosive column of ash. Several steam and ash eruptions have already occurred, including one that dusted towns 40 miles to the north.

    Vancouver is about 40 miles southwest of the volcano.

    "Just because we see lava at the surface now doesn't mean we wouldn't get explosive activity later," said Jon Major, another USGS scientist.

    Even though a new lobe of the existing dome continues to grow at an astonishing rate 2.6 million cubic yards per day, by the most recent estimate Scott said several scenarios are still possible. The dome-building could stop altogether; it could continue in fits and starts for days or weeks; or it could continue building steadily. Right now, the top of the dome is roughly 1,300 feet below the rim of the volcano.

    "If the rate slows down, things can congeal and reseal the system," he said.

    If the lava solidifies and caps the gases now seeping out of the conduit that feeds the volcano, Scott said the underlying magma could become repressurized. In that case, Scott said, seismologists would look for earthquakes much deeper than the half-mile depth detected in the recent flurry of activity.

    Deep earthquakes could indicate an infusion of a much larger reservoir of gas-rich magma. Meanwhile, visitors flocked to the mountain for the third clear day in a row, nearly filling the parking lot at the forest service's visitor center seven miles from the steaming crater.

    "For the last three days, it's been pretty exciting around here," said Scott Hinderman, a park ranger at the Coldwater Ridge Visitor Center.

    Update

    Previously: Steam has puffed out of the crater at Mount St. Helens nearly continuously since clouds cleared Sunday. Scientists expected magma to emerge as lava.

    What's new: Lava oozed out of a new lobe bulging off the south end of an old lava dome, which oozed up in a series of eruptions between 1980 and 1986. Tuesday's development marked the first time lava had appeared at Mount St. Helens in those intervening 18 years.

    What's next: Lava may continue to ooze out; it could explode in a column of ash; or simply stall indefinitely.