Lake Kivu ('kivu' is Bantu and means 'lake' - so a precise name, if not very clarifying) is in the center with Lake Tanganyika below it and Lake Victoria to the east (right). Lake Kivu has a surface area of about 2700 square kilometers (= 1000 square miles). It is nearly a mile (4790 feet) above sea level; has a maximum depth of 480 meters, and is about 90 kilometers long by about 50 kilometers wide.  Ominously, it is estimated to contain 65 cubic kilometers of methane and about four times that much carbon dioxide. There is compelling drill-core evidence of multiple massive explosions in the last two millenia.
On the image above each dot represents an earthquake in the last 40 years.