INDONESIA

INDONESIA.

National Disaster Fund.
Ijen volcanoes complex.
Last stamp in a set of 4, issued on 20.12.1967.
Face value: 5 + 0.50 Indonesian rupiah.
Printing: Photogravure.
Size: 32 x 48 mm.

Catalogs
- Michel No. 595.
- Scott No. B210.
- StampWorld No. 638.
- Stanley Gibbons No. 1181.
- Yvert et Tellier No. 528.
- Zonnebloem No. 598.

The Ijen complex is a group of compound volcanoes located east of the island of Java. It is inside a caldera, about 20 km (12 mi) wide, at the bottom of which are several villages, whose inhabitants benefit from the extraction of sulfur, one of the great economic resources of the region. Mount Merapi stratovolcano, at 2,910 m (9,550 ft), is the highest point in this complex; to the west of its summit is a 1 km (0.62 mi) diameter turquoise crater lake with extraordinarily acidic waters. Within and along the rim of the caldera is a concentration of cones and craters: the active crater of Kawah Ijen has a diameter of 722 m (2,369 ft) and a depth of 200 m (660 ft), producing a curious phenomenon known as blue lava, which are actually electric blue flames produced by sulfuric gas that emerges from the cracks, and can reach temperatures of up to 600 ° C (1,112 ° F).

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Thanks to Vairo Gregori for his contribution (https://ternifil.org/).