Hi DH,
If you look at closely at the Mini PBOs- about half a day to a day before the dip in strain you noted, and on December 26- you can still see little "blips" of red a away from the red line on the graphs.

My prediction is actually based on the increase in strain and now decrease that has occurred at the Ohlone site after the strain meter dip you noted. I don't know whether this too could be partly related to the Sumatra 9.0.

By the way, I didn't mean to cause you much alarm with the prediction as the the magnitude I posted is about the same as a few of the earthquakes you have already experienced in the area over the past few years.
Take care, steve