Famous Indonesian

Mount Galunggung (Indonesian: Gunung Galunggung, formerly spelled Galoen-gong) is an active stratovolcano in West Java, Indonesia, around 80 km southeast of the West Java provincial capital, Bandung (or around 25 km to the east of the West Java town of Garut). Mt Galunggung is part of the Sunda Arc extending through Sumatra, Java and Bali, which has resulted from the subduction of the Indian oceanic plate and the Australian plate beneath the Eurasian plate.

Main article: British Airways Flight 9

The last major eruption on Galunggung was in 1982, which had a Volcanic Explosivity Index of 4 and killed 68 people. This eruption also brought the dangers of volcanic ash to aviation to worldwide attention, after two Boeing 747 passenger jets flying downwind of the eruption suffered temporary engine failures and damage to exterior surfaces, both planes being forced to make emergency landings at Jakarta.

One, a British Airways aircraft carrying 240 passengers, accidentally entered the ash cloud during night time in June 1982 150 km downwind of the volcano. All four engines failed and the aircraft descended for 16 minutes, losing 7,500 metres of its 11,500-meter altitude, until the crew managed to restart the engines.

The following month a Singapore Airlines aeroplane with 230 passengers aboard also inadvertently entered the cloud at night time, and three of its four engines stopped. The crew succeeded in restarting one of the engines after descending 2,400 metres. Both aircraft suffered serious damage to their engines and exterior surfaces.

A hummocky deposit known as the Ten Thousand Hills of Tasikmalaya attracted the attention of early 20th century geologists. Houses were built on the hummocks since they provided good defence against hostile people, and being above the paddy fields were free of mosquitoes and rats.

Originally, it was thought that either it had been formed by a lahar caused by the release of the waters of the crater lake, or that it was man-made; composed of rocks and boulders dumped there after being cleared from paddy fields.

However, in the light of the Mount St. Helens eruption of 1980 and from examination of the Mount Shasta deposits it has become clear that the hummocks are a debris-avalanche deposit. Like these mountains, Galunggung has a horseshoe-shaped crater indicating a massive landslide, and examination of shattered lava blocks revealed them to be similar to deposits on the other two volcanoes. According to radiocarbon dating of samples taken from a lava flow the landslide happened within the last 23,000 years.

Mount Merapi, Gunung Merapi (literally Fire Mountain in Indonesian/Javanese), is an active stratovolcano located on the border between Central Java and Yogyakarta, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548. It is located approximately 28 kilometres (17 mi) north of Yogyakarta city, and thousands of people live on the flanks of the volcano, with villages as high as 1,700 metres (5,600 ft) above sea level.

The name Merapi could be loosely translated as 'Mountain of Fire'. The etymology of the name came from Meru-Api; from the Javanese combined words; Meru means "mountain" refer to mythical mountain of Gods in Hinduism, and api means "fire". Smoke can be seen emerging from the mountaintop at least 300 days a year, and several eruptions have caused fatalities. Hot gas from a large explosion killed 27 people on 22 November in 1994, mostly in the town of Muntilan, west of the volcano. Another large eruption occurred in 2006, shortly before the Yogyakarta earthquake. In light of the hazards that Merapi poses to populated areas, it has been designated as one of the Decade Volcanoes.

On 25 October 2010 the Indonesian government raised the alert for Mount Merapi to its highest level and warned villagers in threatened areas to move to safer ground. People living within a 20 km (12.5 mile) zone were told to evacuate. Officials said about 500 volcanic earthquakes had been recorded on the mountain over the weekend of 23–24 October, and that the magma had risen to about 1 kilometre (3,300 ft) below the surface due to the seismic activity. On the afternoon of 25 October 2010 Mount Merapi erupted lava from its southern and southeastern slopes.

The mountain was still erupting on 30 November 2010 however due to lowered eruptive activity on 3 December 2010 the official alert status was reduced to level 3.