Increased earthquake activity at Mount St. Helens
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Though the increase is not large enough to indicate the likelihood of another eruption, scientists have noted that for the past eight weeks the earthquake rates under Mount St. Helens has been increasing.
Over the last 8 weeks, there have been over 130 earthquakes formally located by the Pacific Northwest Seismic Network and many more earthquakes too small to be located. The earthquakes have low magnitudes of 0.5 or less; the largest a magnitude 1.3. Earthquake rates have been steadily increasing since March, reaching nearly 40 located earthquakes per week. These earthquakes are too small to be felt at the surface.
Once again, these quakes do yet not signal another eruption. They are more likely signs of the mountain’s continuing but long and slow adjustment back to silence after the 1980 eruption. Nonetheless, they bear watching, as a volcano will do what a volcano wants to do.
Please consider donating to Behind the Black, by giving either a one-time contribution or a regular subscription, as outlined in the tip jar to the right or below. Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.
Though the increase is not large enough to indicate the likelihood of another eruption, scientists have noted that for the past eight weeks the earthquake rates under Mount St. Helens has been increasing.
Over the last 8 weeks, there have been over 130 earthquakes formally located by the Pacific Northwest Seismic Network and many more earthquakes too small to be located. The earthquakes have low magnitudes of 0.5 or less; the largest a magnitude 1.3. Earthquake rates have been steadily increasing since March, reaching nearly 40 located earthquakes per week. These earthquakes are too small to be felt at the surface.
Once again, these quakes do yet not signal another eruption. They are more likely signs of the mountain’s continuing but long and slow adjustment back to silence after the 1980 eruption. Nonetheless, they bear watching, as a volcano will do what a volcano wants to do.
–Serendipity, been spending a bit of time at the USGS website.
“…a volcano will do what a volcano wants to do.”
Definitely read the whole post, and follow the link for some interesting info on monitoring & activity.
http://volcanoes.usgs.gov/volcanoes/st_helens/monitoring_earthquakes.html
“Earthquake Monitoring at Mount St. Helens.”
One of the best monitored active volcano’s in the Country.
“An average of 22 events per month of seismic activity are recorded.”
Ref- Volcano’s & the seepage-thread: “majority of gas emitted at Mount St. Helens is water vapor (H2O), followed next by carbon dioxide (CO2), and sulfur gases, including sulfur dioxide (SO2) and hydrogen sulfide (H2S).”
(Still investigating “volume” of volcanic-gas emissions. Government stats are good at concentration-levels but laboring to figure out some sort of world-wide emissions amount.)