Director Brad Peyton brought in Thomas Jordan, USC professor and director of the Southern California Earthquake Center to fact check the script for plausibility. Though both Peyton and lead actor Dwayne Johnson contend that the science portrayed in the film is accurate, Thomas Jordan was quoted as saying "I gave them free advice, some of which they took... but much of which they didn't - magnitude 9's are too big for the San Andreas, and it can't produce a big tsunami."
It is possible for a Nevada quake to trigger an L.A. quake, and for an L.A. quake to trigger a San Francisco quake. The 1992 Landers earthquake, a 7.3 in California's Mojave Desert, triggered a 5.3 quake in Nevada the next day. The 1906 San Francisco earthquake triggered magnitude 5 earthquakes the next day in Santa Monica, Oregon, and Nevada.
After a devastating earthquake in Nepal in April 2015, the film's marketing campaign was adjusted to include information about how to help relief efforts and to give guidance on how to prepare for natural disasters (e.g., a link to the site prepareandhelp.com was added to the newest trailers).
Alexandra Daddario is 14 years younger than Dwayne Johnson, who plays her father, and 15 years younger than Carla Gugino, who plays her mother.
The first thing Alexandra Daddario thought of when she was auditioning for this role was how she grew up in New York City and was in Manhattan during 9/11. "That was really the only thing that I related to as far as a disaster on a grand scale," says Daddario. "It was really interesting to see on that day and in the weeks afterwards how people came together, what they were able to do for each other, and what I found myself feeling, thinking, and doing for the people around me, whether it was strangers on the street or my own family. I really related to it in that way. All the things that you worry about on a day-to-day basis drop away. They don't matter."