I felt compelled to explain my previous map of the MLP globe. Because phyrethefyredemon.deviantart.c… looks nearly exactly like an Earth map.
But now all is revealed.
Gaia is the name of the planet (surprise surprise)
Here we have two rough maps for basic comparison. The one on the left is the canon map expanded. This is what Gaia looked like when the Mane six were alive. Theres a lot that actually has yet to be inhabited or discovered.
On the right is the map I uploaded previously. This is Gaia when my character's Next Gen lives as well as when the main headcanon story I have takes place.
The dates though. At the bottom you can see that the old map says 1814 A.T.S. and the new one is 2016 A.T.S. That's only (counts on fingers) two hundred and two years. Why the hell do the two look so different?!
Gaia is a magical planet (duh). And because of said fact, things work is a way that is vastly different from Earth. As stated in the show, things like plants, animals and, weather patterns that control/care for themselves (ei The Everfree Forest) is weird. That;s mostly because that once ponies learned how to utilize magic to manipulate their environment they did it ALL THE TIME. To the point they forgot it was possible for that to happen. And it happens in powerful and dangerous succession if left to it's own devices. Forests will overgrow everything, animals are essentially savage and ruthless, and weather is disastrous nearly year long. Without ponies and other creatures to keep the magic of the land at bay, Gaia would not be inhabitable by sentient creatures.
The only aspect of Gaia that magic wielding beings cannot control (even though they've tried) is the movement of the Tectonic Plates and basic Geography of the land. Industry can try to shift the land but ultimately they'll be forced to just go with the flow of the land.
In addition, the constant control of every other aspect of Gaia's magic has caused the flow to be shunted to the planet's core and geology. Therefore, the Tectonic plates move at an astounding pace. Cartographers make good money on Gaia because they are constantly needed to adjust and recreate accurate maps.
So yes, that's my reasoning. I'm not a geologist/volcanologist or what have you so my facts will not be 100%.