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.
Ssiscool
Plot hole: Mike Roark is supposed to be the director of an agency that is in charge of coordinating all the resources of the city in the event of a natural disaster, but he doesn't know what a "geological event" is, much less magma?
jbrbbt
Chosen answer: They were in a rush, trying to get things and get out.
MasterOfAll