units 1 and 3 differences

The explosions on the reactors are quite different in magnitude.

Here's unit 1 on 3/12/11:


Here's unit 3 on 3/14/11:


This sat shot show much more damage to unit 3 with obvious steam leakage.  A hydrogen explosion is not big deal (apart from the people there).  It's possible something else happened at Unit 3.