Are we going to see one of these threads every time there's an earthquake in Japan?

It's called the Pacific Ring of Fire for a reason. Frequent strong earthquakes are commonplace there. That's why they build their buildings to withstand earthquakes like this. What they didn't build the Fukushima reactor to withstand was a tsunami.

Unfortunately not much you can do about that. Water ain't called the "universal solvent" for nothing.

Point is, don't worry about earthquakes. Worry about tsunamis.