16 Feb
2013
16 Feb
'13
8:29 p.m.
The NASA release statement is apparently based on calculations by Peter Brown of the University of Western Ontario. I notice that Warren applies the Russian speed estimate to the NASA energy release number but I would guess that Peter Brown elected to use his own number. If his speed was closer to 20 km/s, there is no issue.
From a Sky & Telescope web article I can now confirm that, in Peter Brown's original analysis, the meteor's atmospheric entry speed was indeed 20 km/s ("typical for near-Earth asteroids"). I assume this did not change as he subsequently upped his mass and kinetic energy numbers.