Nyamuragira, just now erupting, is one of the numerous Virunga Volcanoes, which form a large cluster of volcanoes spanning the border of Congo, Rwanda and Uganda, between Lake Ex-Edward (a.k.a. Lake Rutenzege) and Lake Kivu. The largest population center is Goma, on Lake Kivu, along the southern margin of the lava fields from these volcanoes, and made famous in recent years as the site of numerous excursions of warfare, refugee movements, and volcanic lava flows. I’ve written about Goma and a little about the Volcanoes in the Congo Memoirs.
Have a look at the following map:
This map is about 130 km wide (80 miles) and 275 km high (170 miles).
The location of Nyamuragira is indicated by the red arrow. Notice the discontinuous but rather impressive ridge that runs from the lower left corner of the map to nearly the upper right corner. That is the western wall of the Western Rift Valley. The volcanoes just south of the middle of of the map are all within the rift valley. The eastern margin of the valley is poorly defined in this area (it is often the case with rift valleys that one side is better defined than the other).
The two lakes were formerly one lake, and have become separate because of uplift and lava infilling caused by the Virunga Volcanoes, in what is an ongoing process. Several of the volcanoes in this region are active, and there are frequent earthquakes and various eruptions. You can learn about these volcanoes in more detail elsewhere, but here I can give you some broader context regarding the biology and culture history of the area.
To the west (left side of map) on the ridge above the rift valley there are roads linking a number of small villages, agricultural areas, and cities, and in recent decades this has been a fairly heavily populated area. To the west of this is the Central African Rain Forest, sparsely populated. To the southeast (lower right hand corner of the map) is Rwanda, which is heavily populated and has much of its land in agriculture. The valley of the rift is very sparsely populated. This is in part because the valley floor is conducive to the tse tse fly and concomitant sleeping sickness as well as malaria and other diseases. Following a series of late 19th century and early 20th century epidemics (and some warfare) the region was depopulated by colonial authorities and turned into a combination park and buffer zone. Here and there in the valley are plantations or settled areas, but many of the flat areas you see here, as well as north of Lake ex-Edward were wild parkland, only sparsely inhabited at the time the parks were formed.
The borders have been buffer zones in part because of long term distrust and tension between the countries. Rwanda was part of Congo, and administered by the Belgians, but tribally Rwanda has had a complex relationship with the Congo. Rebels operating in the Congo under Mobutu were given refuge in Tanzania and Rwanda, various Tutsi or Hutu linked groups have operated in the Congo, and so on, for many decades. The Ugandan-Congolese relationship is partly tribal but also Colonial. The British colonies (including Uganda) were run very differently than the Belgian colonies, and one result of this was a state of ongoing small scale warfare in parts of the Congo, really from the time of early European exploitation of this area under Stanly through to the present, with a few notable decades of peace here and there. Uganda, on the other and, experienced less of this small scale warfare. This meant that a border was useful to the colonial administers for a number of reasons, and it has been treated as a military resource. In addition, north of Lake Edward there is a tribal link between the ethnic group represented by former evil dictator Idi Amin (Lake Edward was called Lake Idi Amin at one point in time!), with this tribal affiliation running across the border. The nature of the tribal linkage is very complex (one of the more obscure and complex ethnic complexes in Africa). When Amin took over Uganda in a coup, troops from the Eastern Congo, including one man I worked with in the Congo (whom I refer to as JP) went with Amin (JP was the door gunner on the helicopter Amin used to fly to Kampala during the battle.) Later, when Amin was forced out of power in 1978, the machinery of a large part of his army ended up in the northern and western region of this map (along with divers, troops, and other refugees). So during the time I lived in this region, there was a certain background noise of left-drive vehicles and British auto parts dating to a certain time period.
Subsequent to the beginning of the ongoing Congo War and the Rwandan Genocide in the early 1990s and up to the present, there were major disruptions of populations, with villages and cities emptied out or filled with refugees, areas of the parks overrun by various armies and refugee camps set up at numerous locations, with more or less constant fighting going on at some level somewhere on this map in any given year. You have heard of the millions of people who have died in the Congolese war? Look at this map. Many of them died here or very near the margins of this map, which represents a plot of land roughly the size of the US state of Maryland, or between Belgium and Switzerland in size. (Kigali, the Rwandan capital, is just off the map.)
The uplands in this region are either forest or converted to agriculture, and the lowlands are savanna with extensive grasslands and interspersed woodlands. The Volcanoes, since they are mountains rising from the planes, are often islands of rain forest surrounded by grassland. For this reason, they are evolutionary laboratories, and many endemic species live in these forest patches. It is probably true that the mountain gorillas of the region evolved into a subspecies separate from the lowland gorillas and the graueri gorillas because of this island effect. Indeed, the home ranges of all three of these subspecies touch only in the region represented on this map, with the region of the graueri gorillas being entirely included in this map on the western edge of Lake Edward … assuming that this rare subspecies continues to exist at all.
You may have heard of the chimpanzees that are threatened by this lava flow. The mountain chimpanzees of the Virunga region are very important for a couple of reasons including the fact that their isolation from other chimp populations makes them an interesting laboratory for the study of genetic and cultural isolation in a hominoid other than humans. Too bad very little is being done in this area.
But these chimpanzees have yet another point of interest relate to research, including research I’ve been involved in and that you’ve likely already heard a bit about. This has to do with the split between chimpanzees and human ancestors.