Catastrophic damage would be caused .
An earthquake with a magnitude of 10 has never been recorded or is extremely rare. If an earthquake occurred 10 certainly was going to die and there would be a lot and distruction both .
I think that a magnitude 10.0 earthquake possible. It would be physically impossible. Remember that the Richter scale is a log10 scale and an earthquake to reach 10.0 mean that the rock should be viscousness Newtonian properties .
Where and when matter a lot.
In Los Angeles it would be cataclysmic.
All tall buildings would fall, most of L.A. would be destroyed. then as the seismic waves move up the San Andreas it would continue to affect all surrounding areas. As it continues to move toward
San Francisco. We are talking total destruction.