USGS Update 2006-Jan-04 09:30

Potential ash hazards: Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that ash clouds that rise above the crater rim would drift to the northeast.

Recent observations: The pattern of seismicity at the volcano remains essentially unchanged from the previous few weeks. A strong (M 6.7) earthquake occurred at 08:32 UTC (00:32 PST) in the Gulf of California and registered clearly on seismographs across the region including several from the Mt. St. Helens network. Such distant events may take a few to many minutes to reach the seismometers at Mount St. Helens and show up as large, very low frequency undulations in the seismic trace. A technical problem with our satellite telemetry system interrupted the transmission of data from several seismic stations for approximately ten hours last night. Other stations that transmit directly to the observatory continued to provide us with seismic data throughout the outage. As has been the case over the last few months small earthquakes continue to be recorded every 2-3 minutes. This pattern of seismicity coupled with other monitoring parameters suggests the slow extrusion of dacite onto the crater floor at Mount St. Helens continues unabated. Typical winter weather conditions continue to preclude visual observations or field work.

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Standard USGS Update

Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. During such eruptions, episodic changes in the level of activity can occur over days to months. The eruption could also intensify suddenly or with little warning and produce explosions that cause hazardous conditions within several miles of the crater and farther downwind. Small lahars could suddenly descend the Toutle River if triggered by heavy rain or by interaction of hot rocks with snow and ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS) but could pose a hazard along the river channel upstream.

Potential ash hazards to aviation: Under current eruptive conditions, small, short-lived explosions may produce ash clouds that exceed 30,000 feet in altitude. Ash from such events can travel 100 miles or more downwind.

The U.S. Geological Survey and the University of Washington continue to monitor the situation closely and will issue additional updates and changes in alert level as warranted.

My intent with this page is to provide a clearning house for links to the current activity at Mt.St.Helens. Please send me any links of interest that you may come across, whether for permanent sites or for news reports. I'm not going to be able to do this all alone and all help will be appreciated.

(Disclaimer— I have no association with anyone or any organization, and speak only for myself. Links and quotes are provided for information only.)

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