A new theory that has been swirling around the Avatar the Last Airbender fandom recently is that Lin Beifong was actually the one that separated the Air Temple from the rest of Republic City, creating Air Temple Island. Let's explore the validity of this theory and if it could have actually happened.
Air Temple Island, built by Aang and located off the coast of Republic City, is home to the Airbender family and Air Acolytes, as well as colonies of flying bison and lemurs. However, it is also a well-known fact that years before Avatar Korra came to study airbending, Lin Beifong went on an emotional rampage on the supposed “island” following her break up with Tenzin, causing significant damage to the area.
Similar to her Toph, Lin is a master of earthbending in both the Hung Gar style as well as her mother’s own self taught Chu Gar Praying Mantis style. She has excellent seismic sensing abilities and can launch herself high up in the air. She is also able to easily elevate several large boulders at once, even toppling a building on top of Kuvira’s giant mecha suit with the help of Suyin and Bolin.
With this incredible strength in mind, would Lin actually have been able to create a big enough break in the earth when Tenzin dumped her make an island? Picturing the wrath of a broken-hearted Lin, the Air Temple could not have been safe from her rampage. Lin's earthbending skills are as indisputable as her rage, therefore, imagining her being infuriated enough to cause a trench big enough to separate the Air Temple from the rest of Republic City isn’t a difficult feat.
Lin Beifong is one of the strongest earthbender’s in Republic City, if not the world. With abilities that rival Toph herself, Lin has demonstrated earthbending skills similar to even Avatar Kyoshi. That being said, Avatar Kyoshi was able to break away from the rest of the Earth Kingdom by entering the Avatar state. Her power was enhanced by the previous Avatars and therefore was saved her people with ease. In the Avatar State, the Avatar is able to channel vast cosmic energies and knowledge of their predecessor, granting them increased strength and the ability to perform powerful feats of bending, like creating huge tidal waves or sealing a volcano. In the Avatar State, Kyoshi was able to divide a huge landmass from the mainland and push it further into the ocean to the point where it became what is now Kyoshi Island.
Keeping this in mind, does the idea of Lin doing the same thing still hold water? During the height of an incredibly emotional situation -- such as getting her heart broken by Tenzin -- we can see Lin achieving a sort of Avatar State of her own. After all, as we saw with Aang, the state can be triggered by extreme stress. However, the fact that the last person to accomplish this feat was Avatar Kyoshi shouldn't be overlooked, either. Avatar Kyoshi was one of the strongest earthbenders in history, right next to Lin's mother Toph. As a Beifong and a skilled earthbender in her own right, Lin may well have had the skill and power to severe the Air Temple from Republic City creating what is now Air Temple Island. Whether she actually did will have to be left up to fans' interpretation.