In a piece that I am writing, the main setting takes place on an artificial continent about the size of Tasmania. There are three cities on it, with one being much larger than the others. I'm trying to work on a background for it, but time, technology, and plausibility constraints are making me indecisive about what to do. The technological level in this world is only slightly above modern day society, but the timespan between now and then is about 80-100 years. In this time, technology would definitely have progressed further than what I'm envisioning, but I'm trying to keep it close to the present time to invoke some familiarity - this isn't a SciFi piece. Because of this time and technological limit, I've only managed to think up of three background scenarios for the setting that still fits in with the plot. These are: 1. In the process of combating terror attacks, political issues, and economical crises, events occur which separate a large section of an already existing continent. This piece drifts off into the ocean where it is eventually found and 'anchored'. But continental drift takes a long, long period of time, so this is my least plausible backstory. 2. A meteoroid collides with the Earth in the ocean, causing tidal waves that damage much of society. Money that should have gone to technological advancement is instead diverted to recovery. The meteoroid has valuable materials inside, so excavation begins on its surface. A scaffold built around it soon becomes a small city, then expands into a large island. The problem with this is that a meteor of that size might not simply cause tidal waves, but mass destruction of the crust as well, leading to an apocalyptic-like state if the collision is severe enough. This feels more plausible than 1, but I think it needs to be more convincing. 3. This is a similar scenario to 2, except that the meteoroid is deemed a global threat, and a large amount of Earth's energy is diverted into a method of destroying the asteroid, and instead of the main object, its fragments impact into the ocean. Excavation still occurs but since the pieces are scattered, the scaffolds cover much more area. The artificial island is built in the same way, with the scaffolds slowly growing in size. None of these scenarios are without issues, but I'm trying to set this story on planet Earth, on a different continent than any we know of today, and without being too far ahead in the future. So the question I have here is: which background makes the most sense in the context of time, technology and plausibility?