The seventies disaster cycle was dominated by Irwin Allen, whose The Poseidon Adventure and The Towering Inferno had conquered the box office. Universal producer Jennings Lang felt that he could best the “Master of Disaster” with his own star-studded epic. He commissioned a script from Mario Puzo, author of The Godfather. (Puzo wrote ten drafts, followed by numerous re-writes by George Fox and director Mark Robson.)

Los Angeles, 1974: Ex-football hero turned engineer Stewart Graff (Charlton Heston) believes that the skyscrapers and high-rise offices of Los Angeles aren’t safe enough. Graff is unhappily married to Remy (Ava Gardner), the daughter of his boss, Sam Royce (Lorne Green). He is offered a promotion, but learns that it’s an emotional bribe, made at the behest of his wife in exchange for his fidelity.

After a brief but intense tremor, seismologist Walter (Kip Niven) believes that a major quake is going to hit in the next 24 hours, but his boss refuses to face the political fallout if the prediction is wrong.

In pursuit of a thief, L.A. cop Sgt. Lew Slade (George Kennedy) crashes his car into a hedge belonging to litigation-happy owners. Slade is suspended from duty, and goes to a local bar to drown his sorrows.

Sexy Rosa Amici (Victoria Principal) has attracted the attention of her grocer, Jody (Marjoe Gortner). Behind his nice-guy appearance, Jody harbors a violent streak, and moonlights as a National Guardsman.

Daredevil bike-rider Miles Quaid (Richard Roundtree) has invited a talent agent from Las Vegas to watch as he performs his latest stunt; a loop-the-loop ramp with multiple curves and a hoop of fire. Just as he revs up for his audition, the big one hits, an unprecedented quake that all but levels the city.

In the aftermath, Graff and Slade must become heroes, Rosa Amici is pursued by the now psychotic soldier Jody, and Remy is determined to find her husband. If they didn’t have enough troubles, aftershocks may soon cause the dam to break and flood the already beleaguered survivors.

Earthquake pinned a lot of its hopes on a gimmick called “Sensurround,” a series of amplifiers with extra powerful subwoofers, designed to shake up the audience with low frequency waves during the quake sequences. The installation was costly, but the ballyhoo did its job, and Earthquake grossed over 80 million dollars. (Two subsequent pictures also featured this gimmick; Midway and Rollercoaster.)

NBC bought the broadcast rights for Earthquake, and used it to launch their Sunday “Big Event” timeslot. In order to turn Earthquake into a two night event, forty-five minutes of footage was added, most of it newly created. Victoria Principal and Marjoe Gortner returned to shoot new scenes, while Sam Chew and Debralee Scott appeared as a couple aboard an airplane trapped on a crumbling runway.

Despite the success of Earthquake, the disaster genre soon went into decline, with also-rans such as Avalanche, Meteor and Hurricane opening to diminishing returns. Earthquake inspired its own theme park attraction as a stop along the tour route at Universal Studios Hollywood, and as a ride at Universal’s parks in Orlando, Florida and Osaka, Japan.