Acid Lakes: Kawah Ijen

By Kristina Kassis (Fall 2012 GE 101 student)


A famous scene in the 1997 drama Dante’s Peak features the protagonists, played by Pierce Brosnan and Linda Hamilton, attempting to navigate their way across a lake that Brosnan’s character Harry Dalton, a volcanologist, claims has been transformed into corrosive acid by volcanic activity. Upon first watching this scene, I was unsure if this phenomenon was real or merely included in the film for dramatic effect. However, upon further research, I was amazed, excited, and frankly a little frightened to learn that volcanic activity can and actually has transformed many lakes into corrosive acid.  Largest and perhaps most well-known of these acid lakes is located near the Indonesian volcano Kawah Ijen. This lake consists of 36 million cubic meters of acid and has a maximum depth of 760 feet, making it by far the largest acid lake on Earth. At the edge of the lake, volcanic gas eruptions, known scientifically as fumaroles, spew out nearly 4 tons of sulfur daily. In addition to pure sulfur, the lake contains 600,000 tons of hydrogen chloride, 550,000 tons of sulfuric acid, 200,000 tons of aluminum sulfate and 170,000 tons of iron sulfate.  These acids are the most powerful acids on earth and could quite easily burn through human flesh, similar to what happened to Ruth in Dante’s Peak. Perhaps as a testament to this power, an enormous bubble of sulfuric dioxide killed 11 people in 1976 after rising out of the surface of the lake. The local people, perhaps seeking justification for the tragedy, claimed it was the sacrifice asked by the volcano for offering its riches.

Despite the obvious danger of coming within close proximity of such corrosive acids, scientists have made concerted efforts to explore and conduct scientific research on the acid lake located in Kawah Ijen. For instance, in 2008, explorer George Kourounis took a small rubber boat out onto the acid lake to measure its acidity. This was a bold and undoubtedly frightening exploration by Kourounis, and it led to an even more frightening discovery: The pH of the water in the crater was measured to be 0.5 due to sulfuric acid.  It is through daring exploration such as Kouronis’ journey onto the acid lake at Kawah Ijen that scientists are able to learn more and more about these acid lakes and how they form.

In addition to using the lake at Kawah Ijen for scientific purposes, humans have used this natural phenomenon to their economic advantage. The lake is the site of a labor-intensive sulfur mining operation, in which sulfur-laden baskets are carried by hand from the crater floor.  In addition, people from the neighboring area extract sulfur from the crater manually, which is extremely laborious and dangerous work. According to one account:

“To increase efficiency, the workers construct tunnels made out of stone and undulated plates to channel the sulfur-rich fumaroles. The sulfur then leaks, cools down and solidifies inside these improvised channels, which are subsequently broken using metal piles. The recovered stuff contains 99 % sulfur. The sulfur is cut up, loaded into baskets and transported manually out of the crater. The sulfur is then transported to local towns and used for vulcanizing rubber and refining sugar.”

Industrial exploitation of the lake has not been planned so far because Kawah Ijen is active and therefore erupts from time to time, projecting acid to the height of up to 2000 feet and splashing the neighboring areas with an extremely corrosive rain.  Despite the dangerous nature of the lake at Kawah Ijen, humans continue to use the lake to gain profit.

The acid lake at Kawah Ijen has also been featured extensively in the media. For instance, Ijen and its sulfur mining was featured as a topic on the 5th episode of the famous BBC television documentary Human Planet. Additionally, in the controversial documentary film War Photographer, journalist James Nachtwey visits the volcano and risks his own health and well-being while trying to photograph workers as they transported sulfur from the crater. Finally, Michael Glawogger film Workingman’s Death is also about the plight of sulfur workers at Kawah Ijen, Seeing as humans are drawn to anything that they can profit from even at the risk of their lives, I believe won’t be long before Kawah Ijen is a tourist attraction.

Acid lakes like the lake in Kawah Ijen result from a mix of rainfall water with gases coming in from the depths of the volcano, and are also found on the volcanoes Kusatsu-Shirane in Japan and Poas in Costa Rica, demonstrating that this phenomenon is not as rare as one may think. Still, the existence of these lakes, specifically the lake in Kawah Ijen, is an example of a geological phenomenon that is as fascinating as it is terrifying. Each day, I become increasingly aware of nature’s tremendous power. From acid lakes to volcanic lightning, Mother Nature is certainly a force to be reckoned with.

[1] Anetei, Stefan. “The Largest Lake of Acid on Earth.” . Softpedia, 21 2008. Web. 30 Oct 2012. <;.

[2] Measuring the acidity of Kawah Ijen crater lake.

[3] Indra Harsaputra, Kawah Ijen: Between potential and threat’, The Jakarta Post, 19 December 2011.

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s