The reactor has certainly been "stopped", i.e. the control rods have been inserted. While that does stop most of the activity in the core, it does not stop a very significant amount of heat being generated by the remaining activity. This can cause the core to melt, which you really, really, really don't want to happen - so cooling is a must even after an emergency shutoff.From what I heard earthquakes cause the thing to auto shut down, so it is already off and it is just the cooling system giving issues while it is already off.
As explained above, it unfortunately is the danger. However, the scenario looks more like Three Mile Island than Chernobyl.All the reactors were successfully shutdown, so a meltdown is not the danger.
Thanks, this time I was too lazy to do the photobucket transloading shuffle.Also, here is the photo in your link: