In the Daily news this morning, there was an article entitled "Shift detected in ocean fault". It had an interesting lead-in but kind of left me hanging. So...

I went to the Journal Science web site and found the article in the 4/19/01 issue entitled, "A Silent Slip Event on the Deeper Cascadia Subduction Interface".

The basic thrust of the article is that GPS sites in SW British Columbia and NW Washington had been moving landward because of the locked state of the Cascadia subduction zone. Then in the summer of '99, seven sites reversed their direction for a short period of time with no quake being associated with this reversal.

It appears that they are saying that the displacement was about 2 centimeters of aseismic slip over a 50k x 300k area. About equal to an M6.7 event.

The article is also saything that this event proves that movement can occur in a subduction area without a quake.

Another thing that is being worried about is whether or not this kind of activity is a precursor for an M9 1700 type event.

A side not is that this paper was submitted on February 23, 2001 and was accepted on April 9, 2001. Didn't take them long. :-)

Dennis