The T-50B supersonic training jet was part of the "Black Eagles" Republic of Korea Air Force display team, and appears to have crashed into a mountain shortly after take off from the home base of the team - the 8th Fighter Wing at Wonju AB, Gangwon Province.

(Image from Boston.com)

Here is a pic of the T-50B in flight, with the distinctive livery easily identifiable from the above pic:

(Image from flicker.com)

Link - Boston.com:
http://ow.ly/fj2fl