Gets a couple of points for the laugh-at-it value.
It picks up a few minutes after the end of the first installment. A major earthquake has just annihilated part of southern California, clear out to Barstow, with millions of casualties. We see some guys in Vegas, only 150 miles from Barstow, who would have certainly felt such an immense quake; and witnessed news coverage of it. What are they doing? Preparing for a possible danger to Vegas? Mourning the victims of the disaster? No, they're playing poker. The father of the heroine in both movies is winning, so that must be why he's not concerned with his daughter's fate much.
That's only the beginning. We see President Bo Bridges, still looking like he's suffering stomach wall spasms (like in the first movie). The scientist girl goes to discover more seismic problems are coming. Then an inconsiderate quake interrupts her dad's poker game. This opens the obligatory Poseidon Adventure rip off sequence, complete with all the disaster movie trimmings: arguing, wrecked staircases, aftershocks at just the wrong moment, panicky person gets killed, one of the rescuers is related to one of the fleeing survivors, etc.
Then the scientists watch as a major fault cuts across the heartland. Good special effects here, but the story line remains ludicrous. What's right in the way of the fault? A nuke power plant, what else. And so it goes.
Outrageous, but fun.
