First, keep in mind that while those scientists were originally convicted, they were exonerated on appeal. The appellate court's opinion was that the responsibility was on the public official who announced that the area was safe without first consulting the scientists.
Secondly, this case isn't clear cut. Some still fault the scientists for not correctly interpreting the seismology data and not speaking up against the public official who was supposedly to blame. There's a big question around whether these scientists were correct or not in their judgement.
At any rate, this is pretty far from scientific fraud. Seismology (as far as I, a layman, understands it) is not a science where you can make exact predictions. Being wrong about the future isn't fraud, it's just unlucky.
How bad do your buildings have to be to get a 3-digit death toll from something that weak? I'd expect a 3-digit toll for "number of fine-china plates broken".
Christchurch was absolutely fucked by a 6.1 Mw(USGS) magnitude earthquake in 2011 - shallow depth and close to the city so we had severe outcomes. We have reasonably good earthquake building codes in New Zealand.
Poorer countries with more fragile infrastructure could be devastated by a smaller quake - depending on local circumstances.
The only thing that saved Christchurch from far far worse outcomes was that the most dangerous buildings were already empty because of damage from a larger earthquake in 2010.
I admit the log scale means that 6.1 is far bigger than 5.9... However you handwaved 5.x which shows your ignorance of log scales.
We had plenty of aftershocks below 6.1 - they are extremely unpleasant and have awful psychological effects on some people.
And we are hundreds of kilometers away from the major Southern Alps faultline - the equivalent to San Andreas. So we were blessed with some newly discovered minor faultlines.
https://en.m.wikipedia.org/wiki/2011_Christchurch_earthquake