Photographer Olivier Grunewald took these stunning pictures of an Indonesian volcano and sulfur mine that erupted with a spectacular display of brilliant blue lava. The photographer and his friend Regis Etienne have been photographing and filming this phenomenon since they first heard about it in 2008, working under highly dangerous conditions.
For decades, the crater of Kawah Ijen in Indonesia has been used as a sulfur mine. The volcano is located at the edge of the world’s largest hydrochloric acid lake. At night, the liquid sulfur rises and flows through an active vent and creates an otherworldly sight dominated by electric blue lights of the burning chemical. Sulfur combusts on contact with air, liquefies and run in impressive rivers of blue flames, with flares reaching up to 5 meters.
The sulfur is used in the food and chemical industry. The miners extract it through pipes at 115 degrees Celsius, until it crystallizes. About a kilo of the finest crystallized sulfur is sold for 680 Rupiah (under $1). The miners manage to extract two loads in 24 hours, usually working at night in order to avoid unbearably high daytime temperatures.