boiling and steaming grey mud pots and orange sulfur soil in hverir, myvatn geothermal area, iceland

active area boil bubble colorful crack crater crevasse field fissure formation fumarole fumaroles gas geology geothermal grey hole hot spring hverarapara hverir iceland icelandic lake landmark mineral mud pot myvatn natural nature orange pond pool red rock simmering smoke soil solfataras steam sulfur sulfuric sulphating sulphur vent volcanic water boiling steaming pots north east