Yes, typically, a large quake along the baja plate boundary results in a quake, similar in intensity in the Southern Cal area - Hector Mine was one of those.. (as a large example) - it's happened a number of times, but not always.

The odds increase if there's been a progression from further south - say in the state of Oxaca, Mexico, on or offshore, then followed by one in the gulf.. a bit of a progression.

There was a 6.1 in Panama Dec 30
There was a 5.0 offshore El Salvadore...on Jan 3
Now the 6.6 on 1/4/06...

Where next? There is definitely a northerly progression..

Canie