mudpool with colorful sulfuric earth in a geothermal area in iceland

terrain soil sand rock landscape geology boiling bubble colorful colors crack danger earth earth crust energy environment fissure fumarole gas geology geothermal geothermal activity area grey heat hissing hole hot hydrogen hydrogen sulfide iceland mineral mud mud pool pot pots myvatn natural rock rotten eggs scalding simmering smell smoke smouldering soil steam steaming vent sulfur sulphating sulphur surreal vapor volcanic