What areas of California are most susceptible to a devastating earthquake?

San Francisco, San Bernardino, Riversdale, Los Angeles, Big Sur, Sierra Nevada

Explanation:

All of these areas are located near the Two major faults in united states San Andreas and San Jacinto.

These faults creates a lot of friction/movement that made more than 80% of the total slip rate between the North American plates. These regions are considered to be very active and dangerous since many scientist believe they are capable to produce massive quakes with magnitudes of 8 or 9, which will create massive destruction to the cities located on top of them.