Wednesday, August 3, 2011


"Heritage" Mountain Ancient
executive summary by darmansjah godjali

When it appears in the report will be ancient mountain lake area of ​​Lake Toba is caldera-many of us worried. Based on historical records, ancient mountain was not just a monopoly of Lake Toba. One of the other ancient mountain has a caldera that we know as sand Tengger caldera.

Caldera is the center of the eruption was more than 2 kilometers in diameter, while the crater is the center of the eruption with a diameter of less than 2 kilometers.

According to the Head of Sub-Field Observation of Volcanology Volcanology Geological Hazard Mitigation, Geological Survey Ministry of Energy and Mineral Resources Agus Budianto, when contacted from Jakarta, Wednesday (24/11), disclose, Mount Bromo in East Java is a mountain that arise due to the activity of Mount Bromo the ancient past. Unclear how many tens of thousands of years ago ancient mountain erupted.

 Mount Widodaren
Mount anak krakatau

"The Caldera is the caldera of sand that we know today. Around the caldera area of ​​sand and then showed up a few mountains in addition to Mount Bromo, among them is Mount Batok and Mount Widodaren. Caldera model like this is very common in Indonesia. This comes from a huge mountain, megavulkano. In addition to Bromo caldera and the caldera of Lake Toba, Krakatau caldera there is also the birth of Mount Anak Krakatau, which gave birth to the caldera of Mount Batur  child that now exists, and the caldera of Mount Maninjau for, "said Agus.

Mount Batok 
Mount Batur
Mount Maninjau

Lake Toba caldera, which erupted about 70,000 years ago, according to him is the result of volcano activity and tectonic activity.

From the records available at the Chronicle Ngayogyakarta, Mount Bromo erupted on December 28, 1822 and only stopped in January 1823. Earlier, in 1822 eruption of Mount Merapi (Yogyakarta, Kompas, 19/11), Mount Slamet (Central Java), Mount Kelud (East Java), and Mount Guntur (West Java). In the same year, five mountain erupted. Three other mountain is Mount Kelud, Slamet, and Guntur.
Erupted in the year with
Mount Slamet
Mount Kelud
Mount Guntur

While based on the book Volcanoes Indonesia Basic Data published in 1979, Mt Bromo eruption was recorded in 1822 along with the Mount Merapi, Mount Galunggung, and Mount Lamongan. The book catalog reference volcano eruption in Indonesia with this history were collected from a variety of references that exist since colonial times.

Mount Merapi
 Mount Galunggung's Caldera
Mount Lamongan.

Based on the data in the book, Mount Bromo has erupted 43 times as much-plus eruption in 2004. However, the site mentions has erupted 50 times since 1775. Notes from Indonesia Volcano Data Base, the oldest eruption was in 1804.

According to Neumann van Padang (Indonesia Volcano Data Base, 1979) in the caldera of Tengger Mountains of sand there are seven centers of eruption in the two paths intersect, the one on the east-west and the other line northeast-southwest. Mount Bromo is on the axis of the northeast-southwest.

This mountain is the only active volcano of Mount Bromo Ancient heritage. The crater in the north-south line reaches 600 meters, while the crater in the north-south center line of 800 meters. A railroad show, moving towards the center of the eruption of the north. In March 1983 formed a lake in its crater.

In its history, the eruption of Mount Bromo is not flowing lava. Abu vulkaniknya been recorded damaging plantations surrounding the eruption that occurred in 1915 and 1948. Longest eruption occurred in 1842, namely on 24 January to June.

From the same site, written last eruption occurred on June 8, 2004 and actually ended on June 9, 2004. Major eruption occurred only about 20 minutes. Is phreatic eruption, forming a column of ash up to 3,000 meters altitude above the crater rim. Material ejected ash and gravel up to a radius of 300 meters (compared with Merapi ash that can be spread through the clouds heat up more than 4 kilometers).

The data contained on the site of the Group of Scientific Geodesy Faculty of Science and Technology Earth ITB about Bromo Volcano Deformation Monitoring with GPS, A-type volcano is the youngest volcano in the area of ​​the caldera Tengger, namely Mount Widodaren, Chairs, Segorowedi, and Shell.

Tengger caldera itself in the site mentioned a 9 km x 10 km, surrounded by steep cliffs with a height between 50 meters and 500 meters. Mountain range in the caldera surrounded by volcanic rocks of Mount Tengger-called ancient by Agus as Mount Bromo Ancient.

And now, the caldera of sand covered for any activity. In fact, at the Bromo "break", caldera, especially on weekends, will be filled with domestic and foreign tourists. They are willing berdingin-cold to enjoy the dawn's first that can be witnessed from the edge of the caldera. A beauty that dumb ....

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