http://www.youtube.com/watch?&v=gQ6Pa5Pv_io#!

shock wave arrival time was 2 minute 40 seconds. So these observations would typically be over 30 miles away. Reported Infrasound measurements have been reporting energy yields greater than 100Kt i.e. greater than a battlefield tactical nuclear weapon detonation at altitudes approaching 100,000 feet or higher.

If the 2012 DA14 were to hit the earth later today the explosion would be similar or even greater than the Tunguska event.