Between a Rock and a Hard Place

Kawah Ijen

Science Snap (#16): Primary colours at Kawah Ijen

Mel Auker is an Earth Sciences PhD student in the School of Earth Sciences at the University of Bristol. A mathematician by trade, Mel’s PhD uses numerical approaches to better understand past, present, and future global volcanic hazard and risk.

Kawah Ijen volcano forms part of the Ijen volcano complex situated at the eastern end of Java, Indonesia. Kawah Ijen is topped by a 1 kilometre-wide, 200 metre-deep, crater lake. The lake is bright turquoise in colour, and as well as being incredibly photogenic, is one of the most highly acidic lakes in the world and the site of a huge sulphur mining operation.

Kawah Ijen

The summit of Kawah Ijen complete with acidic crater lake and sulphurous fumeroles. Photo credit: Richard Arculus

The Boston Globe has featured Kawah Ijen and its sulphur mine in two of its “The Big Picture: News stories in photographs” in recent years. The articles and accompanying stunning photographs can be found here and here.

The images depict the sulphur in its various, colourful states. Firstly, red, liquid sulphur condenses in stone or ceramic pipes that have been constructed to cap the volcano’s gas-emitting fumaroles. As this sulphur cools, it moves down the pipes and condenses to form yellow deposits. It is these solid deposits that the miners extract and carry in loads of up to 70kg to the weighing station, dubbed “Camp Sulfutara”. To enable them to earn more money, many miners work at night, illuminating the volcano by torch light. As the torches drip, they ignite the sulphur and it burns bright blue – the last of the primary colour trio.