How hydrogen-leaking ‘fairy circles’ might form
By Hannah Richter, Science.
Excerpt: On every continent not cloaked in ice, researchers have discovered strangely barren circular depressions, tens of meters or even kilometers across and as little as a few centimeters deep. Soil probes show these sunken patches, sometimes called “fairy circles,” leak hydrogen gas that is percolating up from within the earth. They have attracted scientists and businesspeople alike for their potential to signal reserves of clean hydrogen fuel. Now, researchers are offering one of the first geomechanical explanations for how they form: from the pressure of upwelling hydrogen gas, which causes a circular patch of land to rise and then sink. Before the new study, which was published on 30 May in Geology, “nobody really understood or tried seriously to understand how these fairy circles are formed,” says Alain Prinzhofer, a geologist and scientific director of Brazilian company GEO4U who reviewed the paper. ...But these circles haven’t been probed all that deeply because of the high cost of boring into the earth. “If we want to tap these fairy circles [for energy], we need to know how deep we need to drill,” says Martin Schöpfer, a geologist at the University of Vienna....