Let me say first that I read this after reading Freefall and Badlands, books 2 and 3 in this series. After reading Badlands, I had to go back and see where a few of the characters started in this series. 
 Aftershock tells the story of earthquake survivors, trapped in the rubble of a freeway. Things are complicated by the fact that some of the survivors are convicts. While there isn't anything new here and Aftershock is basically a story of surviving nature as much as it surviving what people can do to each other. 
 The main characters are Lauren and Garrett. Lauren is a EMT/Paramedic. She immediately goes into action to help the victims. Garrett is key to helping since he has the muscle to get things done. 
 Trapped with the group is a pregnant teen, a grandfather and granddaughter and a climber who spends most of the book in a coma. I'm not saying too much because some of these characters show up later in the series. 
 Overall, this is an action packed story, which I loved. I like that Jill Sorensen lets her male characters feel some emotion. They aren't carboard cutouts. 
 So glad I found some time to read all the books in this series so far. I'm thinking I may have to reread Frefall and Badlands again now that I've read this one. 
 Enjoyable read.