September 26, 2004 3:00 P.M., PDT
U.S. Geological Survey Cascades Volcano Observatory, Vancouver, Washington - University of Washington Dept. of Earth and Space Sciences, Seattle, Washington
Seismic activity at Mount St. Helens has changed significantly during the past 24 hours and the changes make us believe that there is an increased likelihood of a hazardous event, which warrants release of this Notice of Volcanic Unrest. The swarm of very small, shallow earthquakes (less than Magnitude 1) that began on the morning of 23 September peaked about mid-day on 24 September and slowly declined through yesterday morning. However, since then the character of the swarm has changed to include more than ten larger earthquakes (Magnitude 2-2.8), the most in a 24-hr period since the eruption of October 1986. In addition, some of the earthquakes are of a type that suggests the involvement of pressurized fluids (water and steam) or perhaps magma. The events are still occurring at shallow depths (less than one mile) below the lava dome that formed in the crater.
http://www.pnsn.org/NEWS/PRESS_RELEASES/MSH_09_2004.html
Informant: V
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First Long Valley Caldera; Now Mount St. Helens…09-27-04
by Mitch Battros - ECTV
From hurricanes to volcanoes, now no one can argue earth changes are on the increase. So what is the cause?
The latest and most credible research to date, tells us solar influence is the major cause, and more importantly, it is all about “cycles”. The Earth has seen warming trends and cooling trends since its birth. In fact, the Earth has seen more severe swings prior to man's first steps on our planet, and several times since.
See this article published by BBC telling of the latest scientific studies of ice core samples which clearly indicates today’s weather and climate phenomena has been witnessed many times before, and at much worse levels.
Article:
http://news.bbc.co.uk/1/hi/sci/tech/3631764.stm
Over the past two weeks, ECTV has been reporting on Long Valley Caldera “swarm”. Now, Mount St. Helens has experienced the same. In fact, seismologist and volcanologist are predicting a explosion “soon”.
Due to last weeks devastation caused by hurricane ‘Jeanne’ and now two intense ‘swarms’ of quakes related to volcanic activity, I will focus on guest to help explain what today’s breaking news events say about today’s times.
Tuesday September 28th, I will have Jim Berkland – Geologist, as my guest.
St. Helens Activity May Signal Explosion
Associated Press
SEATTLE -- Seismologists believe there's an increased likelihood of a hazardous event at Mount St. Helens due to recent changes in the mountain's seismic activity, and on Sunday the U.S. Geological Survey issued a notice of volcanic unrest.
"The key issue is a small explosion without warning. That would be the major event that we're worried about right now," said Willie Scott, a geologist with the USGS office in Vancouver.
Data from the Pacific Northwest Seismograph Network Web site show the small quakes in red and blue. Initially, hundreds of tiny earthquakes that began Thursday morning had slowly declined through Saturday. By Sunday, however, the swarm had changed to include more than 10 larger earthquakes of magnitude 2.0 to 2.8, the most in a 24-hour period since the last dome-building eruption in October 1986, Scott said.
The quakes have occurred at depths less than one mile below the lava dome within the mountain's crater. Some of the earthquakes suggest the involvement of pressurized fluids, such as water or steam, and perhaps magma. In the event of an explosion, Scott said the concern would be focused on the area within the crater and the flanks of the volcano. It's possible that a five-mile area primarily north of the volcano could receive flows of mud and rock debris.
That portion of the mountain blew out during the May 18, 1980, eruption that left 57 people dead, devastating hundreds of square miles around the peak and spewing ash over much of the Northwest.
"We haven't had a swarm of earthquakes at Mount St. Helens since 2001," state seismologist Tony Qamar said. "Clearly something new is happening." Qamar said if an eruption did occur it would possibly involve ash and steam, called phreatic eruptions. The cause and outcome of the swarm were uncertain Sunday evening. A group of scientists planned to visit the mountain Monday to collect data.
"There's been no explosions, there's no outward sign that anything is occurring. This is all based on the pattern of earthquake activity that is occurring below the dome," said Scott.
Experts believe there is "an increased probability of explosions from the lava dome if the level of current unrest continues or escalates," USGS and the University of Washington Pacific Northwest Seismograph Network in Seattle said in a joint statement. A similar swarm of quakes in November 2001 and another in the summer of 1998 did not result in an eruption. However, the quakes could increase the likelihood of small rock slides from the 876-foot-tall lava dome within the mountain's crater. In the 1986 eruption, magma reached the surface and added to the pile of lava on the crater floor.
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Mt. St. Hellens does it again
http://tinyurl.com/5yeny
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Magma Movement Reported at Mount St. Helens
by Mitch Battros - ECTV
Chief scientist Jeff Wynn of the USGS Cascade Volcano Observatory made the following statement early this morning. “There seems to be some movement in the lava dome”.
The lava dome in Mount St. Helens' crater apparently is growing, possibly a new sign of an impending eruption, but a major explosion doesn't seem likely, a top volcano scientist said today. Wynn said the movement "sort of suggests that we're getting closer" to an eruption that could hurl rocks and ash a few thousand feet into the air.
As reported by KIRO News 7, chief scientist Jeff Wynn emphasized that the estimates were highly preliminary and inexact because there is only one measuring device on the dome, estimating scientists will need about 48 hours to interpret the data more clearly.
Scientists are trying to determine if the quakes are caused by steam from water seeping into the dome or by magma moving beneath the crater.
Early tests of gas samples collected above the volcano by helicopter Monday did not show unusually high levels of carbon dioxide or sulfur, which could indicate the movement of magma.
Seismologist George Thomas at the University of Washington said that on a scale of zero to 10, with 10 being the explosion at the mountain in 1980, the current activity would rate a one. Thomas said any rocks, ash or steam coming out of the volcano would most likely be contained within the crater itself.
"The alerts we're sending out are just to protect hikers and scientists doing research within the crater," he said.
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Mount St. Helens Volcanic Advisory (Alert Level Two) Mount St. Helens Daily Update 9/29/04 5:30 PM PDT
Increased seismicity overnight prompted raising the alert level to Volcano Advisory (Alert Level 2) at 10:40 A.M., PDT, this morning. Throughout the day the seismic energy level has remained at an elevated with a rate of 3-4 events per minute including an increase in the number of events between Magnitude 2 and 3. All earthquake locations are still shallow and in or below the lava dome. In addition, initial data from the GPS instrument on the lava dome that was repaired Monday morning suggest that the site moved a few inches northward Monday and Tuesday, but has since been stable. Such movement is not surprising in light of the high seismicity levels. A USGS field crew continued their deployment of GPS equipment today in order to monitor any ground movement on the lava dome, crater floor, or lower slopes of the volcano. Another gas flight this morning produced a result of no significant volcanic gas detected, as was the case on Monday. Two press conferences were held at CVO to update the media. Tomorrow's field work includes continued GPS deployments.
http://www.pnsn.org/NEWS/PRESS_RELEASES/MSH_09_2004.html
Informant: V