Continuity mistake: In the office tower after the quake there is a panic and workers rush down the stairs only to find them fallen away. After two women fall to their death a man is left hanging on a girder, but falls onto a giant piece of glass. Look at the top of the frame and you will see the airbag shooting our from under it.
Revealing mistake: When the airplane is coming in for a landing, we see an exterior shot of the plane shaking violently well before it has touched down. Clearly the "earthquake" effect is achieved by merely shaking the camera.
Continuity mistake: During the scene at the airport when the tower OK's the plane to land we can see it is a 707 with TWA-like colors of red and white. Then when there is the shot of the plane on the ground it turns into a DC-8 with orange markings. When the plane takes off into the air the camera shows the 707 again.Tobin OReilly