Wednesday, November 3, 2010

Lets story about VOLCANOES in Indonesia

The geography of Indonesia is dominated by volcanoes that are formed due to subduction zones between the Eurasian plate and the Indo-Australian plate. Some of the volcanoes are notable for their eruptions, for instance, Krakatau for its global effects in 1883,[1] Lake Toba for its supervolcanic eruption estimated to have occurred 74,000 Before Present which was responsible for six years of volcanic winter, and Mount Tambora for the most violent eruption in recorded history in 1815.

Volcanoes in Indonesia are a part of the Pacific Ring of Fire. The 150 entries in the list below are grouped into six geographical regions, four of which belong to the volcanoes of the Sunda Arc trench system. The remaining two groups are volcanoes of Halmahera, including its surrounding volcanic islands, and volcanoes of Sulawesi and the Sangihe Islands. The latter group is in one volcanic arc together with the Philippine volcanoes.

The most active volcanoes are Kelut and Merapi on Java island which have been responsible for thousands of deaths in the region. Since AD 1000, Kelut has erupted more than 30 times, of which the largest eruption was at scale 5 on the Volcanic Explosivity Index (VEI),while Merapi has erupted more than 80 times.The International Association of Volcanology and Chemistry of the Earth's Interior has named Merapi as a Decade Volcano since 1995 because of its high volcanic activity.



Semeru

Semeru's eruptive history is extensive. Since 1818, at least 55 eruptions have been recorded (10 of which resulted in fatalities) consisting of both lava flows and pyroclastic flows. All historical eruptions have had a VEI of 2 or 3.

Semeru has been in a state of near-constant eruption from 1967 to the present. At times, small eruptions happen every 20 minutes or so.

Semeru is regularly climbed by tourists, usually starting from the village of Ranu Pane to the north, but though non-technical it can be dangerous. Soe Hok Gie, an Indonesian political activist of the 1960s died in 1969 from inhaling poisonous gases while hiking on Mount Semeru.

Mythology

Semeru is named from Sumeru, the central world-mountain in Buddhist cosmology and by extension Hinduism. As stated in legend, it was transplanted from India; the tale is recorded in the 16th-century East Javanese work Tantu Panggelaran. It was originally placed in the western part of the island, but that caused the island to tip, so it was moved eastward. On that journey, parts kept coming off the lower rim, forming the mountains Lawu, Wilis, Kelut, Kawi, Arjuno and Welirang. The damage thus caused to the foot of the mountain caused it to shake, and the top came off and created Penanggungan as well.


Mahameru/Semeru above mount broma, East Jawa



Anak Karakatau

Verbeek, in his report on the eruption, predicted that any new activity would manifest itself in the region which had been between Perboewatan and Danan. This prediction came true on 29 December 1927, when evidence of a submarine eruption was seen in this area (an earlier event in the same area had been reported in June 1927). A new island volcano, named Anak Krakatau or Child of Krakatoa rose above the waterline a few days later. The eruptions were initially of pumice and ash, and that island and the two islands that followed were quickly eroded away by the sea. Eventually a fourth island named Anak Krakatau broke water in August 1930, and produced lava flows faster than the waves could erode them. Of considerable interest to volcanologists, this has been the subject of extensive study.

Current activity

Anak Krakatau has grown at an average rate of five inches (13 cm) per week since the 1950s. This equates to an average growth of 6.8 metres per year. The island is still active, with its most recent eruptive episode having begun in 1994. Quiet periods of a few days have alternated with almost continuous Strombolian eruptions since then, with occasional much larger explosions.

The most recent eruption began in April 2008, when hot gases, rocks, and lava were released. Scientists monitoring the volcano have warned people to stay out of a 3 km zone around the island. There are several videos of Krakatoa uploaded onto YouTube showing recent footage of it erupting,and inside its crater filmed at the edge of the volcano rim.

On 6 May 2009 the Volcanological Survey of Indonesia raised the eruption alert status of Anak Krakatau to Level Orange.

Anak Krakatau with fresh lava flows


Merapi

Marapi (also known as Merapi or Berapi) is a complex volcano in West Sumatra, Indonesia. Its name means Mountain of Fire, and it is the most active volcano in Sumatra. Its elevation is 2,891.3 metres (9,485.9 ft). A number of cities and towns are situated around the mountain, including Bukit tinggi, Padang Panjang and Batusangkar.

According to legend, the mountain is the site first settled by the Minangkabau people after their ship landed on the mountain when it was the size of an egg and surrounded by water. There are large numbers of upright burial stones in the region which are oriented in the direction of the mountain, indicating its cultural significance.

Merapi the most active volcano in Indonesia

All article take from wikipedia

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