JOHANNESBURG, 15 January (IRIN) - Initial fears of a full-blown eruption by Mount Karthala have calmed on Grande Comore, largest of the three islands in the Union of the Comoros, but authorities remain on red alert as the volcano continues to rumble.
Karthala fired up on Friday night, triggering earthquakes that sometimes exceeded four on the Richter scale. So far there has been no lava flow but Hamidi Soule Saadi, in charge of the Karthala Volcano Observatory (KVO), warned that magma and gas were trapped inside the mountain, "trying to cut a path through towards the outside and to release its energy."
According to a report released by the UN Office for the Coordination of Humanitarian Affairs (OCHA) on Monday, "an overflight of the crater conducted this morning indicated that a lava lake is in formation in the crater, [but is] confined within the crater."
The KVO said there was no immediate risk of a lava flow and three scenarios were envisaged: seismic activity could decrease; cracks could occur on the flank of the volcano, resulting in lava flowing down the side of the mountain; or seismic activity could intensify and increase magma production, which could then flow over the crater.
Seismic activity over the weekend drove frightened people out of their homes in case they collapsed. "We could feel the tremors since Saturday - one about every half hour. People were sleeping outside on football fields and in their gardens," a humanitarian aid worker said.
The island's 300,000 people have held their ground and no population movements have been registered. "There are now fewer earthquakes and their intensity has reduced - the population is not panicking," the UN Resident Coordinator in Comoros, Giuseppina Mazza, told IRIN.
Volcanic activity is common to Grande Comoro. Karthala, which forms most of the landmass of the island and is one of the largest active volcanoes in the world, has erupted, on average, every eleven years in the last 200. It erupted twice in 2005, affecting 40,000 people in April and 175,000 people in November, and again showed increased activity in May 2006.
After the last eruption, volcanic dust and debris covered large areas of the island, while toxic volcanic ash contaminated water supplies, raising concerns about the health of people and livestock, and the effect on agriculture in the polluted area.
According to OCHA, the authorities were remaining on red alert and "have activated the national emergency response preparedness plan. In this respect, a crisis management cell (CMC) has been established, which includes government departments, UN agencies, the Comoros Red Crescent Society, as well as local NGOs and diplomatic missions ... [and the] partners are reviewing preparedness arrangements."
Mazza said the group was "following the situation and inviting people to be prepared", while local media were keeping the population informed. However, there have been reports that the CMC was facing various constraints, mainly associated with a lack of technical capacity and limited access to material resources.