The Nyiragongo and Nyamulagira volcanoes are two neighboring volcanoes located in the western part of the Virunga volcanic chain and have remained the only active volcanoes of this chain for several decades. The seismic activity at these two volcanoes was

The Nyiragongo and Nyamulagira volcanoes are two neighboring volcanoes located in the western part of the Virunga volcanic chain and have remained the only active volcanoes of this chain for several decades. The seismic activity at these two volcanoes was evaluated for the period from 2011 to 2016 in order to observe the chronology of seismic events related to volcanic activity that occurs when these volcanoes present a particular specific states. Using softwares of seismic signal processing such as SWAM and SEISAN, and field observations, we found five events during this time period: (1) the eruption of the Nyamulagira volcano in November 2011, (2) the magmatic intrusion at Nyamulagira in April 2014, (3) the appearance of a lava lake at Nyamulagira in June 2014, (4) the appearance of a small eruptive vent in the Nyiragongo crater in February 2016 and (5) the magmatic intrusion at Nyiragongo in November 2016. From this observed chronology, it has been revealed that the seismic activity during the lava lake period is relatively low compared to that observed in the period without lava lake.