Looks like Thunder is shot off from barges on a river. I know the ones here are.
There are 8 barges- 4 on each side of the 2nd Street - Clark Memorial Bridge, and then the Bridge is also wired from Indiana to Kentucky across the Ohio River to explode at multiple points during the show.
The video of the 2010 fireworks can be watched on this web page
http://www.wave3.com/Global/story.asp?S=12742456
On Sunday -- Thunder will be aired on Arm Forces Television for those serving in the Military.