Mt. Fitzherbert

Recent observations: Scientists from the Cascades Volcano Observatory continue to monitor the volcano remotely. No fieldwork was done this past week, but several crews will be out next week for geologic mapping, maintenance of seismic stations and acoustic flow monitors (AFMs), and collecting photogrammetry control points. The past week's seismic record is dominated by rockfalls in the crater during this hot, dry weather and by glaciogenic earthquakes as the glaciers continue to flow northwards.

Posted by Raoul Ortega at 19:47 | Permalink

Recent observations: Scientists from the Cascades Volcano Observatory made observations July 8, 2008 of Crater Glacier including the co-joined west and east arms of Crater Glacier north of the 1980s dome. They mapped along the northernmost part of the west arm that has advanced about 20 m since May 30, 2008. The advancing glacier ice has moved a bit into the gullies that have been carved by erosion into the Pumice Plain. Calculations from digital elevation data suggests that about 10-11% of the volume of Crater Glacier has been removed over the course of the eruption. Despite incommodious environs at times durning the eruption, Crater Glacier persists, now flanking the 1980s dome on the west, east and north.

Posted by Raoul Ortega at 11:28 | Permalink

Recent observations: This week field crews made repairs to monitoring equipment, continued the summer GPS campaign, and hauled out damaged equipment and spent batteries. They observed a conspicuous deposit of a recent rock and snow avalanche that fell from the south crater wall, just west of the top of the south flank Climbers Trail. Upon reaching the crater floor, the avalanche swept for about 200 meters (650 feet) across the west arm of Crater Glacier, hugging the base of the new lava dome. The exact timing of the avalanche is uncertain, but we know that it happened sometime between June 26 and July 8. Such events underscore the hazards in the crater posed by rock falls and avalanches from the steep crater walls.

Posted by Raoul Ortega at 13:53 | Permalink

RECENT OBSERVATIONS: There was no work in the crater this week, but flights are scheduled for early next week. Seismic and camera maintenance and deformation surveys are planned. Mount St. Helens remains quiet and no fireworks are expected tonight.

Posted by Raoul Ortega at 17:43 | Permalink