While this vast stretch of elaborate geological formations boasts striking views in the daylight, come nightfall the mountains spew electric blue streams of "lava".
Stretching over 22 kilometers (14 miles) in East Java, Indonesia, is the Kawah Ijen volcanic complex.
While this vast stretch of elaborate geological formations boasts striking views in the daylight, come nightfall the mountains spew electric blue streams of "lava".
Believed to be the only location on the planet to consistently exhibit these striking blue flames, the Kawah Ijen volcano’s beauty comes at a price, as the intense levels of sulfur make the air surrounding the complex toxic to anyone who breathes it.
At first glance, the Ijen volcano looks like your bog-standard 600–900°C (1,112–1,652°F) stream of red-hot bubbling molten rock, so what causes the mountain’s sunset transformation into something out of a sci-fi film?
The blue lava phenomenon is caused by an abundance of sulfur pockets in the rock. Sulfur is a chemical element that’s released as the rock liquefies, and while burning, it releases noxious gases like sulfur dioxide. It also creates a striking blue flame.
As this sulfur comes into contact with oxygen it ignites, causing the blue flame that gives the lava the appearance of being entirely blue, but it is in fact just the surface of the molten rock that’s covered in blue flames.