I can't find an official source, but I suspect the blast radius isn't limited to the AZ.

I have systems running in us-east-1, and over the course of the incident, I noticed unexplainable intermittent connectivity issues that I've never seen before, even outside of az4.

East-1 going down always takes some things from other AZs, because there's always something dependent on East-1.

Never trust a crypto company to be honest.

spent the evening looking at SLI graphs waiting for the region to blow up but it never did. only a few envs across many had some degraded EBS vols in the single AZ. it was absolutely a single az (use-az4).