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Report on Karthala (Comoros) — 27 August-2 September 2003

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 August-2 September 2003
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2003. Report on Karthala (Comoros). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 27 August-2 September 2003. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (27 August-2 September 2003)


Karthala

Comoros

11.75°S, 43.38°E; summit elev. 2361 m

All times are local (unless otherwise noted)


Reports of a stream of lava flowing from Karthala towards towns on 30 August were false. Authorities stated that only fume was emitted from cracks on the volcano.

Geologic Background. The southernmost and largest of the two shield volcanoes forming Grand Comore Island (also known as Ngazidja Island), Karthala contains a 3 x 4 km summit caldera generated by repeated collapse. Elongated rift zones extend to the NNW and SE from the summit of the Hawaiian-style basaltic shield, which has an asymmetrical profile that is steeper to the S. The lower SE rift zone forms the Massif du Badjini, a peninsula at the SE tip of the island. Historical eruptions have modified the morphology of the compound, irregular summit caldera. More than twenty eruptions have been recorded since the 19th century from the summit caldera and vents on the N and S flanks. Many lava flows have reached the sea on both sides of the island. An 1860 lava flow from the summit caldera traveled ~13 km to the NW, reaching the W coast to the N of the capital city of Moroni.

Source: Agence France-Presse (AFP)