I have been teach/thought/thought? that on average there are 1000 small scale earthquakes daily on Earth.
That the logarithm of the number of earthquakes is inversely proportional with magnitude....Thus we have, on average, one earthquake of magnitude 5 earthquake, every 10 magnitude 4, and every 100 magnitude 3 earthquakes.
If you like the math:
This is as far as the official science goes.
If there is anything that science does not tell us or anything like the possibility of an artificially induced earthquake...well than the probabilities of what might happen go to infinite.