This was very shallow, and is near where they had the last significant one. I could now plot the earthquake numeric frequency vs. the magnitude and get a straight line (leave that for somebody else :)
That basically means that for every 10 M3's, we get an M4, and for every 10 M4's we get an M5. Actually, 10 is the normal number for most places, but this fault system is so fractal-rough, the number is much higher.
Update: two extra M4ish earthquakes. You can now start counting the M4's! :)