User blog comment:The Devil's Advocate WP/The Historical Geography of Remnant Part 2/@comment-24891101-20140821013958/@comment-14909251-20140821052629

Anthropogenic climate change is definitely something I considered, but I think that would be a bit too blunt. The idea of a supervolcano is another point I considered, but I also note that it is possible a large calamity like the moon beginning to break apart would inadvertently cause a supervolcano to erupt. For instance, a large piece of debris strikes nearby and the resulting seismic tremors activate the volcanic region. Many mass extinctions are increasingly believed to be the result of such a series or events. Like an asteroid hitting Earth is not sufficient on its own to wipe out the dinosaurs, but it causes a chain reaction that is sufficient.

Die definitely suggests a very recent calamity involving the moon, since it talks of a time of peace where the moon was safe and then talking about the peace coming to an end at the same time the moon starts to shatter. While it is just a song, they do seem to hint at plot details and I imagine Jeff does talk to the writers about how he phrases certain things. That does not demand that it all happen at once, since you could have the initial calamity and then just every now and then something happens as a result, possibly due to recurring impacts or the disruption that would result from the moon's altered gravitational pull.

I was certainly tempted to presume the name Remnant had something to do with the moon, but, as your reference to the prologue suggests, it is more directly a reference to them being the remnants of whatever civilization preceded the war with the Grimm.