The deepest well in California was 24,426 ft.
The 7000 number was from the USGS and I will check what it was.
http://205.254.135.7/dnav/pet/pet_crd_welldep_s1_a.htm
I am not crazy?
Oil well are shallower than most earthquakes.
Your 24,426 feet is 7.4 KM (4.6 Mi). That’s about a tenth of your “shallow earthquake” depth.