I’m going to ask and perhaps there’s not a direct answer..if it was a bomb instead of an earthquake ..would there have been an after shock?
Well, since I am not a geologist I am not really qualified to say yes or no. But I have lived in CA for 56 years. Aftershocks seem to be the norm, but not an iron cast rule.
Unqualified answer. The earthquake occurred at the edge of an underwater canyon and it may be possible for a large explosion to cause instability in the wall of the canyon resulting in landslides.
Earthquake map: http://scedc.caltech.edu/recent/Maps/120-34.html
Use Google maps satellite view, 33.837N 119.726W
Just to add some clarification here is how much TNT yield it would take to register 5.0 on the Richter scale:
Richter scale equivalent TNT explosions
Richter scale TNT YIELD EQUIV.
1.0 30 lbs
1.5 320 lbs
2.0 1 ton
2.5 4.6 tons
3.0 30 tons
3.5 73 tons
4.0 1000 tons
4.5 5100 tons
5.0 32,000 tons
5.5 80,000 tons
6.0 1 million tons
6.5 5 million tons
7.0 32 million tons
7.5 160 million tons
8.0 1 billion tons
Largest WWII = 5 tons = 2.4
Massive Ordnance Air Blast bomb = 11 tons = 2.7
The Hiroshima atomic bomb = 16,000 tons = 4.7
Largest thermonuclear weapon ever tested = 50 million tons = 7.2