After Nyiragongo volcanic eruption on May 22, persistent earthquakes have been occurring with Rubavu District in western Rwanda becoming the their epicentre Nyiragongo is stratovolcano – a volcano made up of many layers of hardened lava and tephras— a solid material such as ash, ejected into the air during a volcanic eruption. It is located in the Virunga Mountains of the DR Congo, about twenty kilometres north of the city of Goma and Lake Kivu and west of the border with Rwanda. The earthquakes, which have ranged from 2 to 5 magnitude scale, have also been felt in different parts of the country. According to the latest data, the highest earthquake magnitude recorded, at 11:03 a.m Rwandan time was 5.3. Rwanda Mines, Petroleum and Gas Board’s (RMB) seismic monitor said it originated from Rugerero Sector, in Rubavu District. “Such earthquakes Volcano tectonic earthquakes and are produced by vibrations generated by the movement of magma within the volcano. Pressure beneath the surface of earth increases and the surrounding rock fails, creating small successive earthquakes,” RMB’s seismologist, Tite Niyitegeka, said. A statement on the Nyiragongo Volcanic Eruption, which was authored by Titus Habiyakare, Tite Niyitegeka and Jean-Claude Ngaruye, seismology experts from RMB, warned that earthquakes of elevated magnitude may occur. What damages can earthquakes of such magnitude cause? People around the volcano may be mindful of gases of volcanic origin like acidic and toxic gases including Hydrogen Sulfide (H2S), and carbon dioxide (CO2)), fires, and continuous earthquakes, the experts warned. When present in high concentrations, H2S rapidly results in respiratory paralysis which can lead to death. For CO2, it causes asphyxiation - deprivation of oxygen that can result in death. The risk remains on both Rwanda and DRC sides. Follow-up is being made to find out further risk. Meanwhile some people from DRC were displaced due to lava flow. On March 23, Rwanda’s Ministry of Disaster Management announced that Rwanda received around 8000 Congolese who fled Nyiragongo eruption, but indicated that some of them had started returning home as the eruption subsided. Senator Emmanuel Havugimana said that the eruption-induced earthquakes have socio-economic impact. Based on Richter scale (ML), quantitative measure of an earthquake’s magnitude (size or strength), devised in 1935 by American seismologists Charles F. Richter and Beno Gutenberg, Havugimana said that houses start cracking at the magnitude of 4, implying that the damage is greater as the scale rises. In theory, the Richter scale has no upper limit, but, in practice, no earthquake has ever been registered on the scale above magnitude 8.6. As of May 24, earthquakes had damaged at least 40 houses and a road. “If a person from Kigali feels it, then it is very strong in Gisenyi [Rubavu],” he said, referring to why proximity to the matters, “When tarmac roads start cracking, the scale is at 6.” As felt earthquakes are occurring, people may be informed about what they should do in case a bigger earthquake occurs. One said that earthquake does not kill people but buildings do. This means that people are saved by their self-protection during earthquakes and by the infrastructure designed to resist earthquakes.
