a fumerole with sulfur deposit on mt. sibayak, indonesia.

adventure asia asian covered crater crystalline deposit deposits environment fissure fumarole fumerole fumes gas gases geological geology geothermal gunung heat hole indonesia indonesian landscape mineral minerals mount mountain mountains nature one rock sibayak smell solfatara steam steaming stratovolcano sulfur sulfurous sulphur sumatra travel vapor vent vents volcanic volcano volcanology yellow