Mount Karthala is an active volcano and the highest point of the Comoros at 2,361 m (7,746 ft) above sea level. It is the southernmost and largest of the two shield volcanoes forming Grande Comore island, the largest island in the nation of Comoros. The Karthala volcano is notoriously active, having erupted more than 20 times since the 19th century. Frequent eruptions have shaped the volcano’s 3 x 4-km summit caldera. Karthala is an active volcano and the highest point of the Comoros at 2,361 m (7,746 ft) above sea level. It is the southernmost and larger of the two shield volcanoes forming Grande Comore island, the largest island in the nation of Comoros. The Karthala volcano is notoriously active, having erupted more than 20 times since the 19th century. Frequent eruptions have shaped the volcano’s 3 by 4 km summit caldera, but the island has largely escaped broad destruction. Eruptions on April 17, 2005, and May 29, 2006 have ended a period of quiet. The eruption, which carried a risk of lava flows and deadly volcanic gas, caused the evacuation of 40,000 residents. The crater was clearly changed by the April 2005 eruption. A grey field of ash surrounds the crater and the caldera itself seems larger and deeper. The crater lake, which formed after Karthala's last eruption in 1991 and once dominated the caldera, is now gone completely. In its place were rough, dark grey rocks, possibly cooling lava or rubble from the collapsed crater.
Here are five facts about the Mount Karthala volcano on the Indian Ocean archipelago of Comoros, which threatened further eruption as lava bubbled atop it on Monday:
- One of the largest active volcanoes in the world, the 2,361-metre (7,746 feet) Mount Karthala and its thickly-forested slopes form much of the land mass of Grande Comore, the biggest island in the Comoros chain which lies 300 km (190 miles) off east Africa. Karthala has erupted every 11 years on average over the last two centuries, but it has not caused major destruction. Noxious fumes seeping from cracks suffocated 17 people in 1903 in its worst disaster on record. Scientists at the Karthala observatory say that the volcano's crater, which is about 4 km (2.5 miles) wide, is the largest of any active volcano in the world. Vulcanologists describe Karthala as a basaltic shield volcano with broad, gentle slopes. The volcano erupted twice in 2005, depositing ash on most of the island, forcing thousands to flee their homes and contaminating water supplies. An eruption in July 1991 hurled boulders for several km but caused no injuries. Molten rock dribbling from the sides of the volcano destroyed some 300 houses in the village of Singani in April 1977, although locals managed to flee to safety. An 1860 lava flow from the summit travelled about 13 km (8 miles), reaching the western coast north of the capital Moroni.
Karthala Volcano emitted a plume of ash and/or steam on May 29, 2006. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA’s Terra satellite took this picture the same day. In this image, the translucent gray plume blows westward away from the summit. A spray of bright white clouds appears south of the plume. Karthala Volcano is a shield volcano, deriving its name from a warrior’s shield, with gentle slopes. Together with another shield volcano to its north, Karthala forms Grand Comore Island, or Ngazidja Island off the east coast of Africa. Since the 19th century, Karthala has erupted more then 20 times, some eruptions producing lava flows that reached the sea. The mountain is covered by moist evergreen forest up to about 1800 metres above sea-level. Higher up the vegetation consists of stunted trees and heathland where the giant heath Erica comorensis grows.
Many of the species found on the mountain are unique to the Comoros and four bird species are found only on the slopes of Mount Karthala: Humblot's Flycatcher, Comoro White-eye, Comoro Drongo and Comoro Scops Owl. The mountain's forest is threatened by logging and the spread of agriculture. A nature reserve has been proposed to cover the mountain but it has not yet been created.
