Given the example quoted, not all that far. One article talked about Strasbourg having some minor wobbles, not the entire region. They would have surely seized on the sensationalism of reporting a wider impact.

Of course, there's no clear border. Wobbles will be biggest at the epicentre and get smaller further out.

In any case, you just do the actuarial math, and figure out how much it would cost to wobble-prove buildings in the area in question, and stick that into your cost benefit analysis. It's not like other forms of energy generation are completely without downsides either.