My first reply would have been that the 1977 quake was 6-7 times stronger, which may make a difference. But then I Googled and found a few sources, from which the issue seems a still open question. I read that not only were there lots of dead, but even neighbouring blocks were very differently affacted.

Meanwhile, both theories advanced to explain it have holes: focussing (layers are aligned the wrong way for that) and the reactivation of an old fault line (no aftershocks and no damage along the entire length of the candidate paleo-fault).

<conspiracy theorist>
Maybe it was the Securitate...
</conspiracy theorist>

_{*Lunatic*, n.
One whose delusions are out of fashion.}