Kawah Ljen volcano, located in Banyuwangi in East Java, Indonesia, erupts lava which at night appears to be blue.
Images of this unique spectacle were provided by Olivier Grunewald and Régis Étienne, two French artists passionate about volcanology, who, armed with gas masks and equipment with sophisticated technology, spent 30 nights on the slopes of the volcano taking photos and making extraordinary videos of the “blue lava”.
Let’s take a look:
The secret of the “blue lava”
In fact, along with the usual lava, the volcano emits sulfur vapors whose temperature reaches 500 °C (932 °F), making the surrounding air unbreathable and toxic. In contact with air, the gas burns creating blue flames reaching up to a height of 4 meters.
During the day, the lava is red. Only during the night you can see these flames that make the lava seem like it is blue.
“This unusual color flow is, of course, not lava, as it was unfortunately reported incorrectly by many web sites,” said Olivier Grunewald for National Geographic. “The blue light is actually the result of burning sulphurous gas,” says the photographer.