Some of the earliest maps of California show it to be an island. The "correction" to this misconception didn't occur until 1746 when the Gulf of California and its terminus at the delta of the Colorado River were accurately mapped. For something like two hundred years, the legend persisted that California was a giant island, populated by beautiful women, and possessing vast treasures.
Seismologists have long known that most earthquakes are the result of elastic rebound, a theory that suggests that earthquakes occur because of a build-up of stress along faults. Frictional resistance prevents the fault from moving while stresses accumulate, but at some point the stresses overcome the resistance and the fault moves, generating large earthquakes. The idea was proposed by Professor Harry Fielding Reid after the Great San Francisco Earthquake of 1906, and evidence derived from subsequent earthquakes has confirmed the model.
Professor Avril Primum was the lead researcher. She says that the work of her team along the San Andreas fault in Southern California has provided a crucial addition to the model of elastic rebound. Sometime around 1250 AD, a huge earthquake caused massive slip along the fault and a vast region separated from the edge of the continent. But unlike models that would have left California as a permanent island, Primum's team argues that the elastic nature of the upper crust actually caused the island to rebound back to the edge of the continent, maybe during an epic earthquake reported in the early 1700s.
Avril contends that we don't have to worry so much about California falling into the sea. Sure, it might do it, and Duane Johnson, Pierce Brosnan, and Tommy Lee Jones will have to run around saving stranded people, but ultimately the elastic forces will pull it right back just like a bungee cord. We just need to be patient.