I thought it as soon as I heard about it. Winnie said millions and millions of people died in the quake and the corruption of magic.
The corruption of magic makes sense. It sounds like something a Sentinel might do (and I did feel that ocean-y feeling disappear from around me, which I think was the magic).
I can’t explain the earthquake, but what do I know of the power of Sentinels?
I should be feel stunned/uber-guilty/horrified/disgusted-with-myself/angry-at-the-Sentinel. I don’t feel any of it, because I can’t believe it.