Continuity mistake: When Amy Barnes and Rachel are in the tunnel trying to find out what happened, Rachel falls in the crack of the tunnel, and Amy is thrown back. When it cuts to a different view, Amy Barnes falls or is thrown backwards, yet in the following shot when her hand slips from Rachel's, she falls back again. Also, when she is thrown back by the force, she is thrown back some distance, yet when the smoke subsides she is only about 1 or 2 feet from the crack in the tunnel.
Continuity mistake: At the Department of Geological Science building, the shot then cuts to a woman saying "I can't". The next is a room full of cameras and a couple of guys standing by the cameras near the doorway, yet in the following shot all the guys have disappeared who were standing by the cameras.
Continuity mistake: When Roark, Anne Heche and the other woman are in MacArthur Park, Roark walks away and Anne Heche is quite a few feet away from the other woman, but then she is right next to her without barely even moving. Also, when Anne Heche puts her hand on the woman's neck, in the following shot she is taking her hand away, and in the next shot she is taking her hand away again.
Continuity mistake: When the train boss sacrifices himself by throwing the train driver over the lava flow, he only just manages to throw him past the flow. But in the following shots where it shows the other rescuers view of the lava flowing toward them, the position of them and the lava coming toward them mean they should be burnt by now.
Continuity mistake: There is a shot of a 'hippy' style car with lots of slogans and messages written all over it, melting, but in a shot much later on, the same car is still in amongst the lava flow, when it should have melted already. You can tell its the same car from the megaphone on the roof.
Continuity mistake: Near the end, Roark and Amy are standing over the grid in the street, and when Roark says something like, "I'm not letting you go down there it's too dangerous," Amy is looking down at the grid in the road, but in the following shot she is looking directly at Roark.
Plot hole: When they are trying to find a way to stop the lava from going in to the museum, Tommy Lee Jones has an idea to push a bus up against the museum to divert the lava. The plan works but the lava does not melt the bus like it melted Tommy Lee Jones' car or the fire truck. Even though the bus melts later in the movie, it doesn't melt it instantly like it did with the fire truck.
Add timeA Demon
Continuity mistake: At the start, when Tommy Lee Jones puts the pan on the table, the distance between the milk and the bowl changes from being right next to each other to further apart. Also, the rug is not in line with the edge of the kitchen table, yet when the dog goes to lick up the egg, it is.
Continuity mistake: At the end it starts to rain and everyone is covered in ash, soot, dust etc. However, after a few seconds of rain, all the ash, dust and soot have vanished off Roark, Kelly and Amy instantly.
Continuity mistake: At the beginning of the film, Mike pulls off a frying pan of eggs from the stove, if you look at the eggs, there are virtually none in the centre of the pan, but in the next shot when he goes to put the pan down before it drops, the centre of the pan is now full of egg.
Continuity mistake: When Roark is trying to get a radio, and Emmitt is watching on the big screen in the OEM building, there is a black man behind him who is talking to the guy with the headset on. In one shot the black guy is almost back to back with Emmitt and looks over his shoulder to look at the screen, yet when it cuts, the black guy is talking to the other guy but is not back to back with Emmitt.
Factual error: It is impossible for a volcano to form under Los Angeles. The San Andreas Fault traveling through the west coast is a "Transform" fault in which the Pacific plate and the North American plate creates a fault line that only slide past each other. In order for a volcano to form, two plates need to subduct. Because there is no ripping apart or subduction taking place along a transform fault, there isn't any magma formation to lead to volcanoes.