News Report Update
Chicken-egg question arises over quakes, rockfall from rising dome
from The Portland Oregonian
SEATTLE (AP) — There's a whole lotta shakin' going on at Mount St. Helens these days as the restless peak does what it has for thousands of years: build new lava domes for itself that totter and fall and then serve as the foundation for future domes.
A series of stronger than usual earthquakes — exceeding magnitude 3 — has been reported in recent days by the Cascades Volcano Laboratory in Vancouver, Wash., about 50 miles south of the mountain. The latest was a magnitude 3.1 quake early Thursday that was accompanied by a rockfall.
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.)