4.8 ain't much....but the east coast is really, really not prepared for anything much bigger than that. There is basically zero seismic resiliency in east coast construction practices, from what I've seen.
It is worrying, not just from a safety point of view and risk to life, but it's also going to destroy the tourist season this year, with a knock on effect for all the Greek Islands because some people won't distinguish between the two affected ones and all the others.Someone needs to alarm the Minoans because Santorini is starting to wake up again.