Yea it did take quite a bit of explosives. We have earwitness reports, not second hand, that the explosion did just that. Actually it might not take as much as you might think. I recall being at a firepower demonstration at Ft. Sill. The Air Force Reserve sent a four ship of F-105s. One of those dropped a 500 lb bomb a couple of miles away, and it felt like someone hit you in the chest and stomach with some large, heavy but not too hard, object. Remember that a 500 lb bomb only contains about pounds of explosive material.
Our main earwitness, FReeper PhiKapMom (who I know personally as well as FReeperly) was about 4 miles away from the police range and it rattled her windows. The 911 operators got so many calls that the local (actually OK City 20+ miles away) TV stations had to run a crawl during their 10 PM news (the explosion was about 9:15 IIRC) explaining what the big boom was.
The police range is just south of the big dot on the map at your link along Highway 9. Not many folks in town live more than another 2 miles farther than PKM from the police range, and most live much closer. There's not many houses in the edges of the city proper. And the range is near the southern limit of where there are houses. with the river being the city limit on that side.
Oops.