Update Archives

Overnight, seismic activity at Mount St. Helens has accelerated significantly, which increases our level of concern that current unrest could culminate in an eruption.

Mount St. Helens Update September 30, 2004

The alert remains at a Volcano Advisory. Overnight the seismic energy level increased slightly.

Mount St. Helens Information Statement October 1, 2004

This Information Statement describes a new feature that has developed in the crater of Mount St. Helens over the past few days.

Mount St. Helens Update, October 2, 2004

Yesterday the increasingly energetic seismic swarm of the past week culminated in a small 25-miunute-long eruption around noon from a vent just south of the lava dome.

Mount St. Helens Update, October 3, 2004

Overnight (about 3 am) there was a tremor burst that lasted about 25 minutes. No eruptive plume was detected as a result of this tremor.

Mount St. Helens Update October 4, 2004

Overnight seismic activity increased until a steam (and possibly ash) event occurred about 10:40 P.M. Observers at Coldwater Ridge could see the steam plume.

Mount St. Helens Update October 5, 2004

Yesterday visitors to Mount St. Helens witnessed a 30-minute-long steam-and-ash emission starting at 9:43 a.m. PDT and a 10- minute-long steam-and-ash emission starting at 14:10 p.m.

Mount St. Helens Update, October 6, 2004

Seismicity overnight has remained at very low levels. After the vigourous steam-and-ash emission of yesterday morning, seismicity dropped with individual events becoming smaller.

Mount St. Helens Update, October 7, 2004

The low rate of seismic activity of the past day increased slightly overnight. Earthquakes are presently occurring at a rate of about 1 to 1.5 per minute with maximum magnitudes of about 1.0. Late yesterday.

Mount St. Helens Update, October 8, 2004

Seismic activity continues to be at a low to moderate rate with an overall trend of slightly decreasing energy release over the past 24 hours.

Mount St. Helens Update, October 9, 2004

Seismic activity leveled off overnight after rising gradually for most of yesterday (10/08), with earthquakes up to magnitude 2.4 presently occurring at a rate of about 1 every two minutes.

Mount St. Helens Update, October 10, 2004

Seismic activity has decreased slightly over the past 20 hours to low levels, similar to those observed during the evening hours of October 7. Earthquakes continue to occur at a rate of about 1 per minute.

Mount St. Helens Update, October 11, 2004

Seismicity overnight remained at a low level similar to October 10. Small earthquakes (about magnitude 1) have continued at a rate of about 1 per 5 to 10 minutes.

Mount St. Helens Update, October 12, 2004

Seismic activity remained at a low level overnight. Small earthquakes (maximum about magnitude 1) continue to occur at a rate of about 1 per 5 to 10 minutes.

Mount St. Helens Update, October 13, 2004

Seismic activity remained at a low, but slightly increasing level overnight. Yesterdays visual observations and thermal imaging of the 1980-86 lava dome.

Mount St. Helens Update, October 14, 2004

Seismic activity remained at a low level overnight, little changed from yesterday. Wednesday's visual observations and thermal imaging of the crater focused on the intensely deforming and uplifting area

Mount St. Helens Update, October 15, 2004

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days, weeks, or even months.

Mount St. Helens Update, October 16, 2004

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress.

Mount St. Helens Update, October 17, 2004

Growth of the new lava dome inside the crater of Mount St. Helens continues. As long as this eruption is in progress, episodic changes in the level of activity can occur over days

Mount St. Helens Update, October 19, 2004

In the past 24 hours, seismicity has not changed significantly and remains at a low level overall

Mount St. Helens Update, October 20, 2004

In the past 24 hours, seismicity has decreased somewhat and remains at a low level compared to that observed early in this unrest.

Mount St. Helens Update, October 21, 2004

In the past 24 hours, seismicity has decreased somewhat and remains at a low level compared to that observed early in this unrest.

Mount St. Helens Update, October 22, 2004

Although considered less likely at this time, the current eruptive activity could evolve into a more explosive phase that affects areas farther from the volcano

Mount St. Helens Update, October 23, 2004

The overall low rates of seismicity and gas emission suggest that the lava reaching the surface is gas poor

Mount St. Helens Update, October 24, 2004

The current seismicity is consistent with a continuing, slow rise of magma driving uplift of the crater floor

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