Fairy Circle: A Manifestation of Natural Hydrogen?

ABSTRACT: Fairy circles are natural circular surface depressions devoid of vegetation that are widely distributed on the Earth's surface. These distinctive formations have only recently been associated with natural hydrogen production within their perimeter. Although they are the object of keen interest by scientists in search of clean energy sources, little is known about the origin of the gas and the formation of these fairy circles. In this paper, gas seepage from an underground point source through a saturated porous medium is studied numerically to explore its potential implications for identifying new energy resources. It is shown that, with the hypotheses adopted in the simulations, the formation of a surface depression could not be predicted in the framework of Biot theory of poroelasticity alone. However, the addition of a mechanism of volumetric compaction associated with the presence of gas in the numerical model could be used to match InSAR data collected in the field.