Map of Ijen Crater, where sulfur is mined Bergelut dengan asap nan beracun

The Ijen volcano complex is a group of

composite volcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a ...

es located on the border between

Banyuwangi Regency Banyuwangi Regency (, ) is a Regency (Indonesia), regency of East Java province in Indonesia. This regency also known as ''the sun rise of Java'' because it is located at the easternmost end of Java (island), Java Island. The town of Banyuwang ...

and

Bondowoso Regency Bondowoso Regency () is a landlocked regency in East Java, Indonesia. It covers an area of 1,560.10 km2, and had a population of 736,772 at the 2010 CensusBiro Pusat Statistik, Jakarta, 2011. and 776,151 at the 2020 Census;Badan Pusat Stati ...

East Java East Java (, , ) is a Provinces of Indonesia, province of Indonesia located in the easternmost third of Java island. It has a land border only with the province of Central Java to the west; the Java Sea and the Indian Ocean border its northern ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

. It is known for its blue fire, acidic crater lake, and labour-intensive sulfur mining. It is inside an eponymous larger

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

Ijen, which is about wide. The Gunung Merapi stratovolcano is the highest point of that complex. The name "Gunung Merapi" means 'mountain of fire' in the Indonesian language;

Mount Merapi Mount Merapi (, ) is an active stratovolcano located on the border between the province of Central Java and the Special Region of Yogyakarta, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548. It is loc ...

in central

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

and Marapi in Sumatra have the same etymology. Ijen Geopark stretches across the entire regency which is specifically in the Mount Ijen area, Pulau Merah Beach, and Alas Purwo National Park. It has various geological, biological, and cultural sites. It became part of

UNESCO Global Geoparks UNESCO Global Geoparks (UGGp) are geoparks certified by the UNESCO Global Geoparks Council as meeting all the requirements for belonging to the Global Geoparks Network (GGN). The GGN is both a network of geoparks and the agency of the United Nati ...

in 2023. West of Gunung Merapi is the Ijen volcano, which has a turquoise-coloured acidic

crater lake Crater Lake ( Klamath: ) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is a tourist attraction for its deep blue color and water clarity. T ...

. The lake is the site of a labour-intensive

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

mining operation, in which sulfur-laden baskets are carried by hand from the crater floor. The work is paid well considering the cost of living in the area, but is very onerous. Workers earn around US$13 per day and, once out of the crater, still need to carry their loads of sulfur chunks about three kilometers to the nearby Paltuding Valley to get paid. Many other post-caldera cones and craters are located within the caldera or along its rim. The largest concentration of post-caldera cones runs east–west across the southern side of the caldera. The active crater at Kawah Ijen has a diameter of and a surface area of . It is deep and has a volume of . The lake is recognised as the largest highly acidic crater lake in the world. It is also a source for the river Banyupahit, resulting in highly acidic and metal-enriched river water which has a significant detrimental effect on the downstream river ecosystem. During a scientific expedition in 2001, the pH of the lake was measured at <0.3. On July 14–15, 2008, explorer George Kourounis took a small rubber boat out onto the acid lake to measure its acidity. The pH of the water at the lake's edges was measured to be 0.5 and in the middle of the lake 0.13 due to a high concentration of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

Blue fire crater

Since ''

National Geographic ''National Geographic'' (formerly ''The National Geographic Magazine'', sometimes branded as ''Nat Geo'') is an American monthly magazine published by National Geographic Partners. The magazine was founded in 1888 as a scholarly journal, nine ...

'' mentioned the electric-blue flame of Ijen, tourist numbers have increased. The phenomenon has long been known, but midnight hiking tours are a more recent offering. A two-hour hike is required to reach the rim of the crater, followed by a 45-minute hike down to the bank of the crater. The blue fire is ignited sulfuric gas, which emerges from cracks at temperatures up to . The flames can be up to high; some of the gas condenses to liquid and is still ignited. Ijen is the largest blue flame area in the world. Local people refer to it as ''Api Biru'' (Blue Fire). The other location at which blue fire can be seen is in Dallol Mountain,

Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...

Sulfur mining at Ijen

An active vent at the edge of the lake is a source of elemental

and supports a mining operation. Escaping volcanic gases are channeled through a network of ceramic pipes, resulting in condensation of molten sulfur. The sulfur, which is deep red when molten, pours slowly from the ends of these pipes and pools on the ground, turning bright yellow as it cools. The miners break the cooled material into large pieces and carry it away in baskets. Miners carry loads ranging from up to the crater rim, with a gradient of 45 to 60 degrees, and then down the mountain for weighing. Most miners make this journey twice a day. A nearby sulfur refinery pays the miners by the weight of sulfur transported; as of September 2010, the typical daily earnings were equivalent to approximately $13 US. The miners often receive insufficient protection while working around the volcano and complain of numerous respiratory afflictions. There are 200 miners, who extract 14 tons per day — about 20% of the continuous daily deposit.

Media

Ijen and its sulfur mining was featured in the 1991

IMAX IMAX is a proprietary system of High-definition video, high-resolution cameras, film formats, film projectors, and movie theater, theaters known for having very large screens with a tall aspect ratio (image), aspect ratio (approximately ei ...

film ''

Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a tectonic belt of volcanoes and earthquakes. It is about long and up to about wide, and surrounds most of the Pa ...

'', and as a topic on the 5th episode of the

BBC The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...

television documentary ''

Human Planet ''Human Planet'' is an 8-part British television documentary series. It was produced as a co-production between the BBC Natural History Unit, BBC Worldwide, BBC Cymru Wales, Discovery Channel and France Télévisions. The documentary describes ...

''. In the documentary film '' War Photographer'',

journalist A journalist is a person who gathers information in the form of text, audio or pictures, processes it into a newsworthy form and disseminates it to the public. This is called journalism. Roles Journalists can work in broadcast, print, advertis ...

James Nachtwey visits Ijen and struggles with noxious fumes while trying to photograph workers.

Michael Glawogger Michael Glawogger (3 December 1959 – 23 April 2014) was an Austrian film director, screenwriter and cinematographer. From 1981 to 1982, Glawogger studied at the San Francisco Art Institute, and from 1983 to 1989 at the Filmacademy Vienna, Vie ...

's film '' Workingman's Death'' is about sulfur workers.

Gallery

File:Kawah Ijen volcano, Java.jpg, Kawah Ijen volcano and crater lake, Java, viewed from

Landsat 8 Landsat 8 is an American Earth observation satellite launched on 11 February 2013. It is the eighth satellite in the Landsat program and the seventh to reach orbit successfully. Originally called the Landsat Data Continuity Mission (LDCM), it i ...

File:The cauldron of Ijen Mountain, Indonesia.jpg, The sulfuric lake of Kawah Ijen Mountain's cauldron, Indonesia File:Mount Merapi Ijen A.JPG, Mt. Merapi, Ijen File:Ornament of sulfur.jpg, Sulfur ornaments from Ijen mines File:The blue fire of Kawah Ijen 1.jpg, The "blue lava" of Kawah Ijen File:Kawah Ijen sulfur mining - Indonesia.jpg, Kawah Ijen sulfur mining File:Kawah Ijen sulfur miner - Indonesia.jpg, Kawah Ijen sulfur miner File:Kawah Ijen - Indonesia.jpg, Kawah Ijen

References

External links