Mount Karthala, one of the world's most active volcanoes, this week again scared residents on the major Comoran island, Grand Comore. An impressive but risk-less lava eruption brought back memories from December last year, when 200,000 islanders had to flee and toxic ashes polluted water, soils and pastures. Geologists on Grand Comore now say the lava stream has stopped and hold the eruption is over
- for this time.
Karthala has a great potential of destruction, causing Comoran authorities and humanitarian agencies to be on high alert each time the volcano - the only active on the Comoran archipelago - shows enhanced activity. This week, Comoros again was on alert as Mount Karthala started spewing smoke and bubbling lava.
The eruption started on Sunday, as the first signs of smoke were observed over the mighty volcano - the main landmark on Grand Comore. Vulcanologists soon registered the eruption and sent an alert to the Comoran government, located in the capital Moroni, only around 15 kilometres away from the main crater. Residents were ordered to be on the alert; but not told to evacuate.
This week's eruption rapidly proved to be of another nature than the last ones. Rather than internal explosions in the volcano's crater, lava was slowly simmering lava down the majestic mountain's slope, into its main crater. At this flowing rate and direction, vulcanologists saw now immediate danger for local residents. The only concern was about the occasional molten rock being thrown out of the crater and the possibility of explosions at a later stage.
Residents at the slopes of Karthala naturally were nervous about the outbreak, fearing it could develop into explosions and toxic ash pollution, but no village was evacuated during the week. Villagers mostly kept to their day-to-day businesses, hoping the eruption would not turn more threatening.
For the last two days, seismic activities in and around the volcano have been reduced, and today, geologists report they have ceased all together. The eruption therefore seems to be over for now, but the experts warn Mount Karthala could still decide to continue its activities within the next few days.
Residents therefore seem to have gotten away without damage; this time. Mount Kathala indeed has a violent history, causing constant alert in Grand Comore, also called Ngazidja. In particular the April and December 2005 eruptions had caused great humanitarian problems on the impoverished Indian Ocean island. Toxic ashes from the violent eruption covered great part of the fertile southern slopes of the island.
The April 2005 eruption called for large humanitarian operation coordinated by the Comoran government, UN agencies and the Red Crescent. More than 10,000 islanders had to be evacuated after the ashes had contaminated both water and soils. Also in November and December last year, a toxic ash eruption affected the water supply of 175,000 people on the island, again making a UN humanitarian operation necessary. That eruption was estimated to have displaced between 180,000 and 250,000 people, out of a total population of about 670,000 living in Comoros.
The volcano is known to erupt in a cycle of approximately 11 years. Two strong eruptions in 1972 and 1977 did significant damages as lava flows reached the ocean. In 1977, the coastal village of Singani was partly destroyed by lava flows. In 1860, a lava flow even reached the coast close to Moroni.
Mount Karthala is documented to have erupted more than 20 times since the 1800s. The entire Comoran archipelago - with the four major islands Grande Comore, Anjouan, Moheli and Mayotte (the latter a French colony) - is created through volcanism in geologically modern times. Karthala is the only remaining active volcano of the archipelago.