In one scene, the glass is visible in a woman's head before she gets hit by it.
When Miles (Richard Roundtree) tries to perform his stunt on the track a second time after coming out of the loop and crashing, you can clearly see him riding out of the loop again. The footage used to show the beginning of his new attempt is from a different camera, but from the same take as the first attempt.
During the escape from the underground garage, Denise (Geneviève Bujold} crawls through the tunnel behind the stretcher carrying her son. In the next shot, you can see them entering the hole in the wall that leads to the tunnel.
In the television version, the aircraft on which the newlyweds are flying changes repeatedly from a Boeing 707 to a Convair 880 and back again, each time with a different airline livery. Night-time shots of the plane are borrowed from the film Airport (1970).
In the television version, as the airliner is on its way to Los Angeles, the pilot tells the passengers that they are flying over the Grand Canyon and that he will turn the plane to the right to allow them a better view. In the view from the cockpit, the plane is turning to the left.
During the movie, a comment was made that people weren't sure that the atomic bomb would work until they dropped it. In fact, the first atomic bomb, detonated on July 16, 1945, was mounted on a tower and not dropped.
Most, if not all, passenger elevators have mechanical gravity brakes that are automatically activated in the event an elevator plunges uncontrollably.
In a deleted scene in the movie and in a scene in the television version, it is learned that the big quake measured 9.9. Theoretically, this is impossible. The magnitude of an earthquake depends on the length of the fault on which it occurs. There is no known fault in the world that can produce that large of an earthquake. The largest recorded earthquake was a magnitude 9.5 in Chile in 1960, which scientists attest was a rare event in and of itself.
When the motorcyclist's truck arrives with patients and the injured boy at the hospital, there is an announcement on the overhead speaker saying there is a desperate need for type AB- blood. Type AB+ patients are universal recipients; they can get anything unlike Type AB- patients. Additionally, AB- is the rarest blood type in the U.S. (approx.1 out of 170 people). Type AB blood (both + and -) is not usable except to another person with that blood type. They should be asking for people with Type O- blood, as they are universal donors. Type O+ is the most common blood type.
After the earthquake, in the bar, a woman turns a natural gas valve to shut off the flame that is coming from the broken end. The valve is actually is the "closed" position (with the flame shooting out of the end of the gas pipe), which she then turns to the "open" position, which extinguishes the flame. This is the reverse of how it should work.
When Miles (Richard Roundtree) drives in and out of the loop on his motorcycle, the stuntman is a White stuntman wearing dark makeup.
Valves like the one in the dam would not be affected by an earthquake. Unless the valve body itself was damaged, it should open and close normally.
The dam caretaker drowns in the elevator because it fills with water, yet when the doors to the elevator open, the amount of water that spills out probably wouldn't have come up past the caretaker's knees.
During the earthquake, a truck full of cattle turns upside down; however, the cattle remain in the truck, glued in place on the miniature.
There is no furniture in the collapsing buildings during the big earthquake scene.
During the earthquake scene at the bar, a man dressed in yellow t-shirt and jeans is killed by falling debris from the roof, later, the same man appears being crushed between a wall and the pool table.
Just after the second tremor, the dam engineers inspect the dam. When one of them calls the lift back up and the drowned engineer falls out with the flow of water, you can see him clearly move when he hits the door frame area. His eyes and head move to avoid the gushing water.
When Remy (Ava Gardner) chases Stewart (Charlton Heston) out of the elevator into the lobby, there isn't any separation between the lobby floor and the elevator floor.
If the soundtrack is listened to closely, all the screams and shouts during the earthquake scenes are the same loop over and over again.
The motorcycle on which Miles (Richard Roundtree) is doing his stunt is a Honda XL-250, which has a four-stroke engine. The sound of the exhaust is from a two-stroke engine that was used on Yamaha, Suzuki, and Kawasaki motorcycles.
When Denise (Geneviève Bujold) picks up Corry (Tiger Williams) in the spillway, there is a shiny metallic patch on Corry's back.
When Denise Marshall (Geneviève Bujold) returns to her destroyed house to look for her son, she wanders through the rubble and the top of the living room set walls in the soundstage are visible.
As the farmer drives his tractor towards the scientists in the trench, a shadow of the camera crew can be seen.
(At 58:15) A group whose job it is to study earthquakes would have themselves and their equipment in earthquake-proof surroundings.
The chin strap on Miles' (Richard Roundtree) helmet is unfastened both times he starts to perform his stunt. No daredevil motorcyclists would take that risk.
George Kennedy is shown as a cop in uniform but off duty and is seen walking along a street smoking and in a bar drinking, which surely would be allowed.