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The Daily Insight

What is special about the Kawah Ijen volcano?

Author

Matthew Wilson

Updated on February 27, 2026

Ijen volcano in East Java contains the world’s largest acidic volcanic crater lake, called Kawah Ijen, famous for its turquoise color. The volcano is one of several active stratovolcanoes constructed over the 20 km wide Ijen caldera, the largest caldera in Java.

What causes Kawah Ijen?

But at Kawah Ijen, extremely high quantities of sulfuric gases emerge at high pressures and temperatures (sometimes in excess of 600°C) along with the lava. Exposed to the oxygen present in air and sparked by lava, the sulfur burns readily, and its flames are bright blue.

Is Kawah Ijen volcano active?

Kawah Ijen covers part of the eastern margin. Thousands of years of weathering have converted the pyroclastic deposits into rich, fertile soils which now support coffee plantations. The volcano remains active. The last magmatic eruption occurred in 1817.

Is Kawah Ijen a caldera?

The largest concentration of post-caldera cones run east–west across the southern side of the caldera. The active crater at Kawah Ijen has a diameter of 722 metres (2,369 ft) and a surface area of 0.41 square kilometres (0.16 sq mi)….

Ijen
Geology
Mountain typeStratovolcano
Last eruption1999

Can you swim in Kawah Ijen?

Kawah Ijen High in the rugged mountains of Indonesia’s Ijen volcano complex lies a beautiful, turquoise-colored lake, but taking a dip in its waters would be deadly.

Will lava melt your skin?

Lava won’t kill you if it briefly touches you. You would get a nasty burn, but unless you fell in and couldn’t get out, you wouldn’t die. With prolonged contact, the amount of lava “coverage” and the length of time it was in contact with your skin would be important factors in how severe your injuries would be!

What kind of volcano is Kawah Ijen?

stratovolcano
Ijen is a stratovolcano with a summit caldera. The caldera is about 10 miles (16 km) in diameter. The fertile soils in the caldera are used to grow coffee. This photo is the view to the east across the caldera.

How long does it take to climb Mt Ijen?

Climbing Ijen Crater Indonesia – Climbing Experience The trek up Mount Ijen and down into its caldera takes less than 2 hours on average.

How acidic is Kawah Ijen lake?

The turquoise lake in the crater of the Kawah Ijen volcano looks serene and inviting. It also happens to be the world’s largest acidic lake. The water in the crater lake has a pH less than 0.3 on a scale of 0 to 14 (7 is neutral). For comparison, lemon juice has a pH of 2; battery acid has a pH of 1.

Why visit the Kawah Ijan volcano in Indonesia?

The Kawah Ijan Volcano is a top Southeast Asia bucket list destination and one of Indonesia’s most enticing natural attractions. It is a geologically fascinating place to visit, both for its striking beauty and its peculiar blue fire.

What type of volcano is Ijen volcano?

The Ijen volcano complex is a group of composite volcanoes located on the border between Banyuwangi Regency and Bondowoso Regency of East Java, Indonesia . It is inside a larger caldera Ijen, which is about 20 kilometres wide. The Gunung Merapi stratovolcano is the highest point of that complex.

What is the surface area of Kawah Ijen?

The active crater at Kawah Ijen has a diameter of 722 metres (2,369 ft) and a surface area of 0.41 square kilometres (0.16 sq mi). It is 200 metres (660 ft) deep and has a volume of 36 cubic hectometres (29,000 acre⋅ft). The lake is recognised as the largest highly acidic crater lake in the world.

What is the pH of the water in Ijen Lake?

The pH of the water in 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. Since National Geographic mentioned the electric-blue flame of Ijen, tourist numbers have increased. The phenomenon has occurred for a long time, but beforehand there was no midnight hiking.