mercredi, oct. 24, 2012
vendredi, avril 27, 2012
Le volcan Nyamuragira dans la République Démocratique du Congo pourrait former un nouveau lac de lave dans sa caldeira au sommet. ... [details]
Nyamuragira volcan éruptions
volcan bouclier 3058 m / 10,033 ft
DRCongo, -1.41°S / 29.2°E
Liste des éruptions: 1865, 1882, 1894, 1896, 1899, 1901, 1902, 1904, 1905, 1906(?), 1907, 1907, 1908, 1909, 1912-13, 1920, 1921-38, 1938-40, 1948, 1951, 1951-52, 1954, 1956, 1957, 1958, 1967, 1971, 1976-77, 1980, 1981-82, 1984, 1986, 1987-88, 1989, 1991-93, 1994, 1996, 1998, 2000, 2001, 2002, 2004, 2006, 2010, 2011 (6 Nov, ongoing)
A new flank eruption from started at Nyamuragira on 6 November 2011, from a series of E-W aligned fissures located about 10 km east of the summit caldera. The eruption started with intense ground fracturing (evidence of which was observed during our expedition) and tall lava fountains from several vents, that quickly started to built the western Kimanura cone complex.
Lava flows traveled many kilometers to the north, burning large areas of forest, but caused no damage to infrastructure, since the area is not populated. Tall fountaining lasted about 1 week, and moved to intense spattering from active lava-lake filled vents and strombolian explosions. Depending on the wind direction, areas surrounding the vents received up to about 1 meter of lapilli and scoria fallout. A second cluster of vents opened about 1 km down-slope on the same fissure system in early January and produced lava fountains our first expedition group in January was lucky to observe from close. Another, similar sized complex of vents built up quickly the so-called east Kimanura vent complex. Similar to the activity of the western complex, lava fountaining merged into a form of intense spattering from boiling lava lake activity and continued to fee large lava flows traveling to the north. As of 2 February, the eruption is still continuing.
It seems likely that this eruption ranks as one of the volcano´s largest during the past 100 years, both in duration and total lava volume erupted.
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