This (almost) daily post intends to follow up the activity changes of volcanoes all over the world.
This post is written by geologist Richard Wilson who specializes in Volcano seismicity and Armand Vervaeck. Please feel free to tell us about new or changed activity if we haven't written about it. -
July 9, 2012 volcano activity
Another relatively quiet day in volcanoland.
El Hierro (Spain) is currently experiencing another burst of seismicity. Successive episodes are now more feeble (in terms of magnitude and duration) than the previous. It may be that this latest episode of unrest is on the wane.
Another volcano-tectonic earthquake swarm appears to be ending at Popocatepetl (Mexico). Both spasmodic and harmonic tremor accompany small (but numerous daily) exhalations of gas and ash at the volcano.
More interesting seismicity recorded by the new (UW-USGS) seismic network at Newberry volcano (OR). A single event at 30 km depth beneath the volcano's southwest flank. The crust beneath the Newberry edifice is only 30-35 km thick and petrologic studies of lavas erupted in the region indicate that they are stored at or near the crust-mantle interface. I will contact a researcher at UW to see if this event was a deep-low frequency event (indicative of fluid movement).