We analyzed the seismic data collected in the database of the Goma Volcano Observatory, for the period from 2002 to 2011. Based on the location of the various swarms of Long Period Earthquakes, migration of epicenters were assessed in order to estimate the weakness areas which are the ways for dyke intrusions at Nyiragongo and Nyamulagira volcanoes, the two very active volcanoes the Western Branch of the East African Rift in the Democratic Republic of the Congo. We found that the intrusions of dykes occur in two main perpendicular weak axes: the NE-SW axis generated by tensional forces from the East African Rift actions, and the NW-SE axis generated by divergent forces from the actions of magmas of both volcanoes.