That's surprising, children's reactions to natural reactions not been studied until 1992. When we had the Loma Prieta quake in 1989, I was working at Hewlett-Packard in Palo Alto. They had a professional come in to talk to us adults about lingering reactions after the quake. Several parents mentioned that they were having problems with their children, things like reversals in toilet training and, of course, nightmares. (I think we all were having nightmares for a while after the quake.)