Aliens. Missiles. Explosion. Locals in Russia’s Yamal Peninsula say any of these could be the reasons behind large craters that have been appearing suddenly in the frozen terrain!

They were initially discovered by helicopter pilots in 2013-14. Subsequently, satellite images have revealed that there may be far more craters than ever found anywhere else in the world! And the numbers only seem to be increasing.

The Yamal Peninsula, known for its harsh frozen climate and rich gas deposits is now in the news for craters that are mushrooming dangerously close to its gas fields.

What Are Sinkholes?

Sinkholes form when the ground underneath the surface gives way. This could happen for several reasons: when the soil gets saturated with water and becomes too heavy, it collapses crushing the voids (gaps) in between. Acidic water can eat away layers of underground soil as well.

If there is already a big fracture in the layer below the surface – say the layers are made of highly porous limestone karsts, then water seeping through can expand the cracks and suck the topsoil in.

Another explanation could be triggered by oil drilling. The seawater fills up natural air pockets inside the soil, which becomes heavy and saturates. This leads to a cave-in. In most circumstances, the erosion of underground layers is a slow and gradual process -- hidden from sight.

Growing Craters In Siberia

Many of the craters found in the Yamal Peninsula have been found quite close to gas deposits. This has led to speculation that the two may be connected.

Both years - 2013 and 2014, had been much warmer than usual which could have triggered a rapid thawing of the permafrost (the frozen surface soil). Methane, a gas trapped below the permafrost in large reservoirs, would then escape.

This theory has been supported by a nearby lake which is believed to have been a sinkhole that later filled with water.  Methane gas seeping from the bed of the lake is clearly visible as white plumes. This constant release of gas could potentially weaken the pressure underground, leading to further cave-ins and sinkholes. Researchers feel these could even be blow-holes, caused by underground explosions of gas. To make matters worse, gas companies are drilling in the region.

Yamal literally translates into ‘end of the world’ in the local dialect. Scientists are conducting more research to better understand the terrain and the risks. Geologists and oil and gas companies will be keenly tracking their progress.

Courtesy SiberianTimes, HowStuffWorks