Nyiragongo is a stratovolcano, and one of the worlds only volcanoes with a persistent lava lake. Several eruptions have been recorded in recent times at this volcano, including at least 18 between 1884-2001.
In January 2002 an eruption occurred along a 20 km fracture network that extended south of the volcano. Using ERS-2 and RADARSAT-1 Wauthier et al. (2012) identified that the eruption involved a 3 km deep (6 x 40 km long), and a shallower 2 km thick, pair of dykes. It is thought that magma fed the deeper dyke over the previous 10 months, which caused then fed the shallower, eruptive, dyke. Measurements of the surface of Lake Kivu suggest that 70-80 cm of subsidence occurred at Goma Harbour in the month that followed the eruption (Tedesco et al., 2007).
Since May 2002 there has been continued activity at Nyiragongo. Between 1996 and 2010 Toombs and Wadge (2012) have identified using InSAR 7 periods where the deformation could be described by shallow near-vertical dykes, which go on to feed eruptive fissures. They also note that between eruptions, the caldera summit and the NNW trending fissure zone subsides < 3-5 cm/yr.  In the 6 months prior to the 2010 eruption a 10-km wide zone centred on the caldera inflated by 1–2 cm. Toombs and Wadge (2012) attribute this deformation to the compression of a magma chamber which is 3-8 km deep.