Bobbi Flekman

Members
  • Content Count

    5
  • Joined

  • Last visited

Posts posted by Bobbi Flekman

  1. As I posted in the other St. Helens thread...

    Mount St. Helens erupted at 12:03pm PDT. The activity continued for about

    24 minutes, creating a steam and dust plume that reached about 10,000 feet

    elevation and drifted SSW toward Portland, OR and the Pacific coast.

    Steam vented from a location at the southern edge of the dome where the

    dome edge is covered by glacial ice and debris from the southern crater

    wall. On Thursday afternoon N-S linear cracks were observed in the glacier

    ice there, implying a slight uplift beneath the ice. Video images of the

    eruption showed steam, some possibly superheated, venting from a limited

    area and carrying blocks and fines upward into a mostly-white steam plume.

    A USGS helicopter flight at the time of the eruption detected no thermal

    anomaly with a thermal IR device, implying that this was a steam explosion

    only, without magma being directly involved. Live video images taken by

    helicopter at roughly 2:00pm PDT show a large hole in the glacial ice at

    the edge of the dome, with a layer of gray ash and ejected blocks extending

    from it over the ice only toward the SW.

    The ongoing seismic activity decreased substantially during the eruption,

    but then has rebounded at least slightly since the eruption ceased.

    There have been no reported mudflows, but a possibility of slightly

    increased flow of water out of the crater.

    A USGS team was installing a seismometer on the NW flank of the volcano at

    the time, but they were not affected by the event and were not in the path

    of the plume.

    Presumably an update will soon be posted at:

    http://vulcan.wr.usgs.gov/Volcanoes/Cascad...urrentActivity/

  2. From the Volcano News Letter. I'm an amateur geologist/volcanologist.

    Mount St. Helens erupted at 12:03pm PDT. The activity continued for about

    24 minutes, creating a steam and dust plume that reached about 10,000 feet

    elevation and drifted SSW toward Portland, OR and the Pacific coast.

    Steam vented from a location at the southern edge of the dome where the

    dome edge is covered by glacial ice and debris from the southern crater

    wall. On Thursday afternoon N-S linear cracks were observed in the glacier

    ice there, implying a slight uplift beneath the ice. Video images of the

    eruption showed steam, some possibly superheated, venting from a limited

    area and carrying blocks and fines upward into a mostly-white steam plume.

    A USGS helicopter flight at the time of the eruption detected no thermal

    anomaly with a thermal IR device, implying that this was a steam explosion

    only, without magma being directly involved. Live video images taken by

    helicopter at roughly 2:00pm PDT show a large hole in the glacial ice at

    the edge of the dome, with a layer of gray ash and ejected blocks extending

    from it over the ice only toward the SW.

    The ongoing seismic activity decreased substantially during the eruption,

    but then has rebounded at least slightly since the eruption ceased.

    There have been no reported mudflows, but a possibility of slightly

    increased flow of water out of the crater.

    A USGS team was installing a seismometer on the NW flank of the volcano at

    the time, but they were not affected by the event and were not in the path

    of the plume.

    Presumably an update will soon be posted at:

    http://vulcan.wr.usgs.gov/Volcanoes/Cascad...urrentActivity/