I don't know if you remember the old Dianetics commercial, the one with the erupting volcano, but two book trailers this month utilize the image to varying degrees of success.
First, I Am America by Stephen Colbert (AKA, the writers of The Colbert Report) works more as a badly realized skit with the Volcano eruption moneyshot as the climax. However, the Gawker Guide does a much better job of staying true to the medium and format, lending to an overall cohesiveness (bonded by the viscus lava, I suppose).
The Final Word: Based on the trailer alone, I'd pass on I am America and give it a D (however, I love the show so I'll let this slide and buy it anyways).
As for the Gawker Guide, I give the trailer an A. It raises expectations and definitely delivers. Buy it.