Balcones Fault You can "experience" the "inside" of an earthquake right down the road in San Marcos, TX. http://www.wonderworldpark.com/core.htm
Isn't the Palo Duro Canyon near Amarillo the second largest in the continent? Or only the 2nd largest in the US? Anyway.. I believe the fault runs up that area, down through the Permian basin, then on down through the Hill Country. Or not... http://www.lib.utexas.edu/geo/ggtc/ch3.html Mostly south of San Antonio, Hill Country only... but... That may not be accurate any more.
Interesting update from the Chronicle http://www.chron.com/disp/story.mpl/headline/metro/5682532.html
Yeah, they call it that because after visiting, you WONDER why you paid $14 to stare at a hole in the ground.