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Main African volcanic activities are situated along the Great Rift Valley, a hundreds of kilometres wide depression, which spans from Mozambique in the south to Valley of Jordan in the north, 6500 km long. About 80 % of the volcanoes are found alongside or within the Great Rift Valley.
These are one of the most spectacular but least-known volcanoes on the planet. In the past 150 years, more than 110 eruptions have been reported from 18 locations, while another 112 volcanoes have been diagnosed as potentially active.
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ERUPTION NEWS
7 January 2004
PITON DE LA FOURNAISE
Reunion Island, Indian Ocean 21.23S, 55.71E; summit 2,631 m asl
On 7 January 2004 at 09h30 a seismic event started beneath Piton de la Fournaise and significant surface deformation was recorded. On 9 January eruption tremor started near Nez Coupé de Sainte Rose. A 300-m-long fissure, cutting the 1931 crater, produced a small 2km long lava flow. The eruption stopped on 10 January around 12h00.
Since the 1998 eruption, Fournaise has been very active with multiple eruptions every year, sometimes lasting only few days or even hours. Below is a brief overview:
- First eruption in over 5 years begins 9 March 1998. April-June lava flows on Plaines des Osmondes and beyond. New lava flow traverses 12 km across the E flank. Activity ends with fissure eruptions outside the caldera in September 1998
- A fissure eruption begins 19 July 1999
- September-October 1999 eruption generates lava fountains and flows
- Eruptions in February, March, June, and July 2000
- 12 October-13 November 2000 eruption near July eruption site
- Eruptions during late March 2001 and on 11 June 2001
- 11 June-7 July 2001 eruption; two lava flows block highway
- Erupting fissures on 5-16 January 2001 in l'Enclos Fouqué caldera
- Fissure eruption 16 November-3 December 2003 sent lava to the sea
- Eruption on 30 May 2003 generates lava flows within Dolomieu crater
- Lava flows in Dolomieu crater; eruption ends 7 July 2003
- Lava eruption from three fissures during 22-27 August 2003
- Seismic crisis and a new SSW-flank fissure on 30 September 2003
Background. The massive Piton de la Fournaise shield volcano on the island of Réunion is one of the world's most active volcanoes. Most historical eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest of three large calderas. This latter caldera is 8 km wide and is breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows within the caldera, have been documented since the 17th century.
1 September 2003
KARTHALA
Comoro Islands, Indian Ocean 11.75N, 43.38E; summit elev. 2,361 m
According to news reports, Observatoire Volcanologique du Karthala scientists noted a steady increase in seismicity at Karthala over the past 3 months. Around 100 earthquakes occurred per day in August in comparison to 1-2 per day in June.
23 August 2003
PITON DE LA FOURNAISE
Réunion Island, Indian Ocean 21.23S, 55.71E; summit elev. 2,631 m
A new period of heightened seismicity began beneath Dolomieu crater on 23 August 2003. The first fissure opened in Bory crater around 21h20, and the second fissure opened at 22h10 on the N flank at about 2,450 m altitude. Both fissures were active for short periods of time. The final fissure opened at 23h30 around 2,200 m altitude on the N flank. A lava flow traveled into Plaine des Osmondes.
13-18 July 2003
OL DOINYO LENGAI
Tanzania, eastern Africa 2.75S, 35.9E; summit elev. 2,890m;
Paul Hloben stayed on Lengai for 6 days. The volcano was erupting all the time what can be best described as Strombolian activity - magma was ejected by gases in discrete bursts resulting in showers of lava fragments up to 25 cm in size normally 3 to 20 metres high collecting on the flanks of the cone. The individual bursts occurred in 2 to 5 second intervals. The eruption usually lasted between 8 to 15 minutes following the equal time of rest.
At times, spectacular jet-like explosions sent blobs and a poor ash cloud up to 50 metres high (if not more), showering the crater floor with small (up to 5cm) blobs up to 30 metres from the cone. Ash fell sometimes outside the crater, blown away by strong winds. This activity was usually longer lasting (between 15 to 25 minutes) with powerful bursts every 1 to 3 seconds.
This activity occurred from a new cone that has grown up from 6 to 8 metres in two days (13 to 15 July). The other, white cone was also active. It was completely roofed, with a lateral opening 1mx0.5m (not visible in the picture) about one metre below its rounded top. The activity usually not coincided with the black cone. It was bursting lava blobs up to 5 metres high after 2 to 3 puffs of steam (like a locomotive). Occasionally strong bursts sent lava fragments up to 15 metres high. Similar activity occurred in early August during Fred Belton Expedition.
21-28 June 2003
PITON DE LA FOURNAISE
Reunion Island, Indian Ocean 21.23S, 55.71E; summit elev. 2,631m
After ceasing for a few days, eruptive activity recommenced at Piton de la Fournaise on 21 June around 2330. Tremor was sometimes recorded at Dolomieu crater and lava flows were emitted from the crater. Volcanism continued through at least 28 June.
30 May-1 June 2003
PITON DE LA FOURNAISE
Reunion Island, Indian Ocean 21.23S, 55.71E; summit elev. 2,631m
An eruption began at Piton de la Fournaise on 30 May around 1155 at Dolomieu crater in the area where the December 2002 collapse occurred. The eruption was preceded by a slight increase in seismicity on 28 May, which included a small seismic swarm. Another swarm took place on the morning of 30 May, and at 1155 tremor began beneath Dolomieu crater. Then the eruption began, producing a lava flow that reached a length of ~400 m and a width of 250 m in the western part of Dolomieu crater. In addition, lava fountaining was observed until ~1400, after which most surface activity ceased. By 1 June at 1000 no tremor was recorded, marking the end of the eruption.
2 May 2003
NYAMURAGIRA
Democratic Republic of the Congo 1.408S, 29.20E; summit elev. 3,058 m
A report issued on 2 May noted an inferred renewal of activity on Nyamuragira. Residents living in the villages of Katale and Tongo, the settlements closest to the volcano, reported rumblings on 30 April, in addition to clear noises of individual explosions. At the same time on 30 April the closest seismic station (Katale) recorded 18 clear explosion signals, directly followed by an important tectonic earthquake located beneath the volcano. In the next hours seismometers registered 7 type-C events and another important tectonic earthquake.
Background. Africa's most active volcano, Nyamuragira is a massive basaltic shield volcano N of Lake Kivu and NW of Nyiragongo volcano. Lava flows from Nyamuragira cover 1,500 sq km of the East African Rift. The 3058-m-high summit is truncated by a small 2 x 2.3 km summit caldera that has walls up to about 100 m high. About 40 historical eruptions have occurred since the mid-19th century within the summit caldera and from numerous fissures and cinder cones on the volcano's flanks. A lava lake in the summit crater, active since at least 1921, drained in 1938. Twentieth-century flank lava flows extend more than 30 km from the summit, reaching as far as Lake Kivu.
2 May 2003
NYIRAGONGO
Democratic Republic of the Congo 1.52S, 29.25E; summit elev. 3,469 m
UN peace keepers in the Democratic Republic of Congo provided volcanologists an early May helicopter flight. This presented very clear views of Nyiragongo, including the scene inside the active crater. Viewers reported seeing a significant plume containing gas and ash rising high above the volcano. Such activity is typical at Nyiragongo, with its restless lava lake. The lake appeared slightly larger than when seen during a field excursion to the crater rim during 22-24 April. The field excursion measured the plume at 5-6 km a.s.l. The also noted 5 distinct vents, almost continuous emissions of scoria, an agitated molten-lake surface that included emerging gas, and splashing lava thrown 50-60 m high. Occasional waves of lava rolled across portions of the crater floor and walls. Excursion members also witnessed crater-wall collapses taking place along the NW and S fracture zones. Widely felt earthquakes also continued in the region, presumably related to extension along the massive East African rift system.
Monitoring is done from a small observatory building located in Goma, ~18 km S of the Nyiragongo crater. Extremely fluid, fast-moving lava flows draining from the summit lava lake in 1977 caused many fatalities, as did lava flows inundating portions of the city of Goma in January 2002.
10 February 2003
NYIRAGONGO
Democratic Republic of the Congo 1.52S, 29.25E; summit elev. 3,469 m
Beginning around 10 February volcanic activity increased at Nyiragongo. Fine ash covered cars in the city of Goma and at 1142 a long-period earthquake occurred for more than 2 minutes that was followed by several small events and an increase in tremor amplitude. Residents near the volcano noticed an increase in plume height, a change in plume color from white to black, and a sustained rain of ash and Pele's hair. As of the 14th, Pele's hair continued to fall in Goma and an ash plume was visible rising at least 5 km above the crater. At this time seismicity was probably lower than the previous week. GVO stated that the Pele's hair that fell in Goma was produced by lava fountaining inside Nyiragongo's crater. Residents in Goma and surrounding villages experienced a water shortage due to the contamination of rain water, which is their only source of water.
4 -14 January 2003
ERTA ALE
Ethiopia; 13.60N, 40.67E; summit elev. 613 m
A team of French scientists who visited the summit of Erta Ale on 4, and 13-14 January noted significant changes in morphology and activity at the volcano in comparison to several months previous. As has been the case for decades, a lava lake was present in the W part of the S pit crater. It was 120 x 80 m in size and its surface was ~100 m below the crater rim. Observers saw lava fountains spraying above the lake, as well as convection within it. The lava lake and resulting platform were higher than when observed in April 2002. Abundant SO2-rich gases were released that were not noted during earlier visits.
16 November - 3 December 2002
PITON DE LA FOURNAISE
Runion Island, Indian Ocean 21.2S, 55.7E; summit elev. 2,631 m;
All times are local (= UTC + 4 hours)
After 3 months of high seismicity at Piton de la Fournaise and three small seismic crises, a strong seismic crisis with several hundreds of earthquakes started on 15 at 23h36. The earthquakes were accompanied by large deformation at the summit of up to 300 microradians. An eruption began on the 16th November 2002 at 04h33. Fissures opened on the volcano's E flank between 1900 and 1600 m-asl and lava flowed down the E flank. A small cone formed on one of the most active fissures around 1600 m-asl.
On the 30th, 329 seismic events were recorded that were all located about 1 km a.s.l. beneath Dolomieu crater. A lava flow in the Grand Brulee area approached the national road, crossing it around 23h00. By about 05h00 on 1 December the lava flow had reached the sea. Source: Smithstonian Institution
4-9 August 2002
OL DOINYO LENGAI
Tanzania, eastern Africa 2.75S, 35.9E; summit elev. 2,890m;
During 4-9 August 2002, Ol Doinyo Lengai was in a heightened state of volcanic activity. A group visiting the volcano for 5 days saw episodes of sudden explosive lava fountaining from cracks and fissures in the crater floor. Sulfurous gases were also unusually strong in the central crater. Around 0210, part of an expedition camp in the crater of Ol Doinyo Lengai was destroyed by extremely fluid pahoehoe lava flows. A local guide received several second-degree burns on one foot when material in his tent was ignited by the lava. Source: Fred Belton
25 July - 3 August 2002
NYAMURAGIRA
Democratic Republic of the Congo 1.41S, 29.2E; summit elev. 3,058 m
Helicopter flights on 1 and 3 August revealed that the eruption that began on 25 July at Nyamuragira continued at a high rate. Two volcanic cones were visible growing on the eruptive fracture. The cones were built by the accumulation of spatter and ash from two very active 100- to 200-m-high lava fountains. Two large lava flows moved quickly and joined below the lowest cone to form a main flow. The main flow (estimated to be 15 km long) moved toward the NNE and changed direction after a few kilometers to move toward the NE. Many lateral overflows were visible on the E side of the main flow. The front of the main flow appeared to be very wide and lava covered a wide area, though it remained within the National Park boundaries. Permanent tremor was registered. The Alert Level remained at Yellow. Source: Smithstonian Institution
1 August 2002
NYIRAGONGO
Democratic Republic of the Congo 1.52S, 29.25E; summit elev. 3,469 m
A helicopter flight over Nyiragongo on 1 August revealed a thick, dense plume rising from the crater at a high velocity. The inner crater was completely filled with dispersed gas, preventing visibility of any fresh lava that may be in the crater. No red glow has been seen during recent nights, but the permanent sustained tremor recorded on all stations confirmed that the volcano remained active with magma moving beneath it. Some individual shocks were recorded around the SW flank of Nyiragongo. The Alert Level remained at Yellow. Source: Smithstonian Institution
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MOST ERUPTIVE VOLCANOES
* Erta Ale (Ethiopia)
* Ol Doinyo Lengai (Tanzania)
* Nyiragongo (Congo)
* Nyamuragira (Congo)
* Mt. Cameroon (Cameroon)
* Fournaise (Reunion-Indian Ocean)
PICTURE RIGHT
The African Great Rift Valley, responsible for volcanic activity, divides the continent. In ten million years it will be flooded by a shallow, expanding sea. Please note that the western rift (Cameroon region) is not included in this illustration.
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