Hawaii isn't the only series of islands formed from underwater volcanic eruptions. In 2014, a massive eruption formed the new island of Hunga Tonga-Hunga Ha'apai. But there's something about this island that has scientists stumped. Following is a transcript of the video.

Watch a brand new island form. You're watching the evolution of a brand new island. Hunga Tonga-Hunga Ha'apai formed in 2014 after an underwater volcanic eruption breached the surface. Nearby tourists filmed the huge explosion. Flights had to be diverted around it. When the smoke cleared, a small island was visible. It's located about 400 miles southeast of Fiji in the Pacific.

It's only about a mile long. It was expected to wash away after a few months. Now, three years later, it's still here. These images show how it's been holding up over the years. This is the first time satellites could see an island forming. Scientists still don't know how the island has lasted this long. One theory is that warm seawater interacted with the ash to form a hardier rock surface. Scientists soon hope to run chemical analysis on rock samples. To unlock the secrets of this young, mysterious island.