The expected 2011 episodic tremor and slip (ETS) event has done the unexpected by starting months early. These events happen in the deep part of the Cascadia Subduction Zone, "down dip" from the area where the Juan de Fuca Plate is completely locked against the North American Plate. These "slow earthquakes" reoccur every 14 months on average and have been remarkably consistent over the past decade. Another of these events was expected to begin in late October, early November 2011 but has begun months early. Details from the UW, Pacific Northwest Seismic Network here.