The island was formed by ancient volcanic activity.īromo is one of Java's most active volcanoes, located on top of the 16-kilometre-wide Tenegger Caldera in East Java, with a summit elevation of 2329 metres. With around 200 million inhabitants, Java is the most populated island in Indonesia and also the world. With the tunnel acting as an overflow, the water level was restricted to 134.5 metres and the volume of lake water was reduced from 20-40 million cubic metres to a residual volume of 1.8 million cubic metres.Indonesia is located within the Pacific 'Ring of Fire' volcano belt and has more than a hundred active volcanoes within its territory. One year later the tunnel was finally complete. During the construction of the tunnel, accidents repeatedly occurred which were caused by the crater wall collapsing in the unstable terrain, resulting in the work being interrupted in 1923. The eruption itself cannot be influenced by this. This was constructed above all to contain the risk of lahars. Only in August 2008 was level two of four suspended.īack in 1920, the water level of the crater lake was kept at a specific height by means of a drainage canal along its western bank with a diameter of 2 m and a length of about 980 m. Consequently the alert level was reduced step by step. An explosive eruption of the volcano did not take place, but a large-volume lava dome formed which finally filled the cater lake completely. The Center for Volcanology and Geological Hazard Mitigation placed the region around the volcano on red alert on October 16, 2007, whereupon the inhabitants within a radius of ten kilometres (at the time about 135,000 people) were evacu¬ated. Furthermore, the water of the crater lake changed from a greenish colour to white. The water temperature in the crater lake increased, as did seismicity. Kelud was most recently active at the end of September 2007. In 1990 the volcano then spewed lava and toxic fumes, killing 30 people. After this devastating event the term lahar, denoting a volcanic mud flow, was introduced as an internationally used technical term. In 1919, more than 5,000 people died during an eruption. During a strong eruption in 1586 more than 10,000 people were killed. More than 30 eruptions of Kelud have been documented since 1,000 AD. For this reason, violent volcanic eruptions and earthquakes occur again and again in this region. It is located in eastern Java on the so-called Sunda Arc, a 5,000 kilometre long subduction zone along which the heavy oceanic Indo-Australian Plate subducts beneath the continental Eurasian Plate at a speed of up to 6.7 cm/year.

The 1,731 metre high stratovolcano Kelut is one of the most dangerous of a total of about 130 active volcanoes in Indonesia.

According to the Volcanic Ash Advisory Centre in Darwin, Australia, the ash cloud reached a height of 15 kilometres. The airports of Solo and Surabaya even Yogyakarta in Central Java were closed due to poor visibility and the hazard posed to the aircraft engines by ash particles. Thirty-six villages are located in the evacuation zone.

After the spectacular eruption of Kelud, more than 200,000 people had to be evacuated on Friday (February 14, 2014) within a radius of ten kilometres from the volcano summit.

Java volcano