Kawah Ijen, The Most Amazing Indonesian Volcano

Kawah Ijen volcano is one of several volcanoes located in the 15km diameter Ijen Caldera in E Java, Indonesia. The caldera rim is still visible in places, but has been partially buried by Kawah Ijen, 2800m high Gunung Merapi (not to be confused with Merapi volcano near Yogyakarta), Gunung Rante and Gunung Pendil volcanoes. The caldera is today largely filled with coffee plantations. Kawah Ijen harbours a large warm acidic crater lake and an active sulphur mine. Due to its easy accessibility, turqoise lake and unique sulphur mining operation, the crater is regularly visited by tourists. The last recorded magmatic eruption of Kawah Ijen was in 1817. The eruption displaced the crater lake and resulted in inundation of several villages along the drainage route. Phreatic eruptions have been reported in 1796, 1917, 1936, 1950, 1952, 1993, 1994, 1999, 2000 (also minor ash emission), 2001, 2002 (with minor ash emission), (?), 2011. The increasing frequency may reflect better reporting since the explosions are usually confined to the lake and cause little or no damage.



The walls of the Kawah Idjen lake are light ocher, but the water has a turquoise color, with emerald reflexes. The temperature of the water is of 34o C, and sulfur bubbles float on the surface. The surroundings are covered by a sulfur powder. The smell is pungent and irritating, filled with sulfur dioxide. From place to place, sulfur pours at a temperature of 120o C, like bright red trails, which gradually solidify, turning lemon yellow.

In the irritating and corrosive atmosphere of the crater, people's only protection is a piece of fabric used for covering their mouths and noses. Each worker can transport 40 to 70kg (90 to 155 pounds) at once on the abrupt slopes of the volcano, using bamboo ladders where the slope is too steep.