For communication purposes, Amateur radio would be the most common and accessible. Although, I have a feeling the internet would be much more resilient than it

For communication purposes, Amateur radio would be the most common and accessible. Although, I have a feeling the internet would be much more resilient than it may be given credit for; it just might not be a World Wide Web, maybe a Regional Wide Web or City Wide Web.... Someone else had it right too, if there were a large enough catastrophe to knock out the infrastructure supporting the internet entirely - you would be concerned with many other things.