Not about low balling. For a tannerite or other home made smallish explosive device to be heard much less FELT over multiple counties, then the counties would have to be very very small. About the size of a football field.

Unless it was a rental truck packed with fuel and fertilizer.

If you haven't noticed, these booms have been being felt and heard for quite sometime now all over the word. I have heard some myself in TX. They are very strange and not "explosive" like in any way