TV grab shows a giant hole that has appeared in Yamal, one of Russia's most isolated northernmost regions. [Photo/people.com.cn]

TV grab shows a giant hole that has appeared in Yamal, one of Russia's most isolated northernmost regions. [Photo/people.com.cn]

MOSCOW - Researchers are to investigate a giant mysterious hole that has appeared in one of Russia's most isolated northernmost regions, state television reported.

It was unclear what had caused the gaping crater, about 100 meters in diameter, filmed from the air in Yamal, which means 'the end of the Earth' in the local Nenets language, where temperatures plummet to -50 degrees Celsius (-58 degrees Fahrenheit) and the sun barely rises in winter.

An expedition to collect soil and water samples from the site was planned for Thursday with two researchers from the Siberian-based Center for the Study of the Arctic and a scientist from Russia's Academy of Science, state news outlet Vesti reported.

TV Zvezda, broadcast by Russia's Defence Ministry, reported the person who shot the video footage as saying the hole appeared to have been caused from below and that the darker soil around its top indicated the effect of high temperatures.

Yamal, inhabited by indigenous reindeer herders, is one of Russia's richest regions in natural gas. The hole was found near the Bovanentsky gas field, leading to speculation that it could have been caused by an underground explosion.