Massive 3km crack gapes in Arizona

Parched land in Arizona has opened up in a massive crack around 3km long.

At some points the split gapes almost 3m across and down as far as 9m. In other spots it's narrower, less than 2.5cm across.

"These narrow sections sometimes have open voids underground, so collapse of the overlying material is possible. This is how the deep open portions of the fissure formed," geologist Joseph Cook told LiveScience.

Mr Cook works with the Arizona Geological Survey (AZGS) and has been monitoring the massive fissure in the Tator Hills area since December 2014.

For the first time drones have been sent up to map the gash in the earth, and footage shows humans standing on the edge of the crack, dwarfed in comparison.

Mr Cook told LiveScience the crack will probably continue to get bigger, but his only safety concerns are if someone tries to explore it and gets stuck or buried.

"The crack is worrisome, but it's out in the middle of the desert with nothing nearby," he says.

"These form because the ground is sinking and the ground is sinking because we're pumping water out and we have for many years."

He says it's likely the crack has extended due to recent heavy rain, which softened the earth and allowed it to further collapse.