Factual error: That truck they're driving had better be fitted with a couple of powerful rocket motors, because they outdrive a pyroclastic explosion, which would be moving at about 300kmh. We see the pyroclastic cloud just metres behind the truck - it would overtake them in seconds.
Factual error: After the volcanic eruption, there's a scene where we see our heroes going across a lake, which has been turned to acid by the lava. If this acid is strong enough to corrode the propeller, then surely the fumes would be destroying their lungs, in which case they should be dead, or close to it.
Factual error: In the scene where Paul and the National Guardsman are leaving the motel for the final time after packing up, Paul follows the two Humvee's out of town. Being a Guardsman myself, I know for a fact that all civilians would be in front and Humvees would be following them. It is standard operational procedure.
Factual error: The scene in which the main characters are in the ranger station truck and are driving across the lava flow, you see the tire getting absolutely covered in lava, flinging it inside the wheel well, plus the bottom of the truck is basically only an inch or two above it. How did the gas tank and the fuel lines survive that miraculously without melting or bursting? The heat would literally boil the fuel inside the lines and the truck would no longer be able to run.
Factual error: When inside the boat going across the lake turned to acid, they are moving at a high speed. But all a sudden when they lose the prop, the boat is at a complete stop and actually turning. 2 problems with that scene. The momentum of the boat at a high speed would have continued moving it forward for quite some time. It would not stop all a sudden. And when he is using his shirt to row the boat, the boat would have turned, because he was only paddling on one side.
Factual error: When being rescued from the crater, Harry tells the helicopter that he is 600 feet below the rim. But earlier, when first the other scientist and then Harry went down into the crater it took a very short time - that could not have been 600 feet. And also from the look of the distance it was more like 150 feet. (00:13:10)
Factual error: Harry was able to drive across the lake as the truck he was in was fitted with a snorkel. The other cars that drove into the lake would have immediately stopped as the engines would have hydrolocked. Therefore the car that hit the truck wouldn't have been able to get there in the first place.