The Watchers Posted by Chillymanjaro -June 23,2013
Mount Shasta volcano showed signs of elevated seismicity since June 11, 2013. The volcano typically displays a relatively low rate of earthquake occurrence. Earthquake-Report connects the recent uptick in seismicity at Mount Shasta, the Greenville earthquake sequence, several deep (30-40 km depth) events beneath the Klamath Mountains to the west, as well as recent small earthquakes at Lassen Peak; and relates them with ended slow-slip event along the subducted slab beneath the region. Slow-slip occurs when the overlying crustal plate periodically (and only partially) detaches from the underlying (subducting) oceanic plate and slowly slips (millimeters/day) westward (contrary to its normal eastward movement) over a period of days to weeks. The events occur about every 14 months beneath Washington and British Columbia, about every two years beneath Oregon (one just occurred there earlier this year!), and yearly beneath Northern California.
