Hi Ara. Sorry I can’t disclose the nature of the program as it is proprietary and is still being tested. The probability is based on the number of quakes per year inside a 65Km radius and a 5-day window for the target area.

I use a 40Km radius for quakes in California, Oregon and Washington with a 5-day window and a 65Km radius and a 5-day window for all other areas.

The biggest problem I had was getting the magnitude of the quake. Without knowing how much stress had accumulated in the area I never really knew the magnitude of the expected quake. Take Care…Don in creepy town