Disaster movies, which predate the zeitgeist’s fascination with a world falling apart around us, are always great measures of the state of the Hollywood art of special effects.

In “San Andreas,” you will believe the ground is rippling under Los Angeles, the cracking collapse of the Hoover Dam and a tidal wave that submerges San Francisco.

But what sells this formulaic corker of Apocalypse Porn is the cast. Paul Giamatti, as a Cal Tech seismologist who has just this minute uncovered a way to predict earthquakes, wears the horror of what he sees and what he knows is to come, in his eyes, wide with terror.

Carla Gugino and Alexandra Daddario let panic, grief and relief when the shaking ends wash over them in what feels like real time.

And the actor nicknamed for a geological feature earns that nickname all over again by being that sturdy force of nature the whole movie is anchored on. Dwayne “The Rock” Johnson is an ex-Army chopper pilot, now with the L.A. Fire Department’s air rescue unit, a man uniquely set up to save his soon-to-be-ex-wife (Gugino) and college-student daughter (Daddario, of TV’s “True Detective”). Johnson believes what he’s seeing — buildings tumbling like dominoes, fires erupting, his chopper crashing, the sea fleeing San Francisco Bay — and we do, too.

The script and director Brad Peyton (“Journey 2: The Mysterious Island”) never escape the time-honored formula for disaster movies — the warnings, unheeded; the shortsighted builder (Ioan Gruffudd); the disaster-imposed love interest (Hugo Johnstone-Burt) thrown together with the hot coed.

But here’s what he and this production get exactly right. The cast is spot on.

The first death has meaning and pathos, as does the last one. The medical moments and derring-do can feel far-fetched. But the science feels solid. God help them if they’re only bluffing. It’s a “swarm event” that runs up and down California’s infamous San Andreas Fault. Because … geology!

Sure, we know where it’s going, from the moment the ground starts shaking until it finally stops, several “swarms” later. But “San Andreas” is a well-executed reminder of why we don’t need to fret over the zombie apocalypse when there are plenty of real calamities Mother Earth can throw at us. And that Hollywood’s best craftsfolk at Digital Domain, House of Moves and other effects houses are getting even better at re-creating those worst-case scenarios we love so much — in our movies, at least.