Peruvian President Pedro Castillo declared an environmental emergency after an oil spill from high waves caused by the Tonga volcanic eruption contaminated several beaches. Photo: Martin Mejia ...

Tonga, officially known as the Kingdom of Tonga, is an archipelago located in the South Pacific Ocean, east of Fiji and west of Samoa. It consists of 176 islands, of which only 36 are inhabited.

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.