As others have mentioned, parts of America's infrastructure is reinforced - of particular note, the internet specifically was born out of ARPAnet and substantial portions of it are still likely to reinforced. It might not even go down, just... you probably wouldn't have access to it.

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More pointedly, a lot of the actual high risk areas for such as event (the one that immediately jumps to mind is transformers) can be protected with minimal preparation, and we'd have warning (this is something that gets tracked). What this amounts to in practice is that it'd likely cause an absolutely immense amount of damage, but major areas of vulnerability would largely be able to mitigate impacts through disconnection/reinforcement/etc. As a result while it'd be a disaster the likes of which has no modern equivalent, it'd be recoverable.

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If you meant more on a personal level? It'd largely be shutting things down/disconnecting them.