In the week and a half since Mount St. Helens rumbled back to life, it has quieted somewhat. The steady earthquakes have slowed as have the intermittent plumes of ash and steam. Though the alert level has been dropped to Alert Level 2, scientists are still wary of the volcano, warning that it could still erupt with little or no warning. Changes in activity levels, possibly for the next few months, are to be expected says the United States Geological Survey (USGS) Cascades Volcano Observatory.
Mount St. Helens’ most recent eruption began on October 1, 2004, when it released a large cloud of ash and steam. Small plumes rose from the volcano in the succeeding few days, and it was in this period, on October 4, when the ALI sensor on NASA’s EO-1 satellite took this image. Here, the volcano’s crater is the dark shadow in the tan circular region on the left side of the image. White clouds of steam stream away from the crater across the image. The lake to the south of the crater is Swift Reservoir on the Lewis River. In the days since this image was taken, only light clouds of steam have risen from the crater where hot volcanic rock has turned the volcano’s glacier to steam.
NASA image courtesy Lawrence Ong, EO-1 Mission Science Office, NASA GSFC
- EO-1 - ALI