Living amidst Mazuku (dry gas vents): linking hazard and impact perceptions to improve risk communication in Goma, Virunga volcanic province

Abstract. Communication of diffuse carbon dioxide (CO₂) degassing hazards remains less explored than more visible volcanic hazards such as eruptions, despite their persistent and sometimes fatal impacts on exposed populations. This study examines how residents living amidst mazuku (CO₂-rich dry gas vents) in western Goma, Virunga volcanic province, perceive both the hazard and its impacts, and how these perceptions are interrelated to inform risk communication. A structured household survey was conducted among 573 household heads to assess perceived proximity, likelihood, and magnitude of mazuku across different environments of daily life, as well as experienced impacts, their perceived likelihood, and expected severity. Measured distance from each surveyed household to the nearest mapped mazuku vent was also calculated using geographic information system tools. Descriptive analyses, Spearman correlations, linear regression, and multinomial logistic regression were used to explore relationships between perception dimensions, socio-economic factors, and actual spatial exposure.

The results reveal clear spatial differentiation in hazard perception. Mazuku is often perceived as spatially close in domestic environments but less likely and less intense, whereas public and less more intense. Levels of experienced impacts are strongly associated with the perceived likelihood controllable spaces, such as streets, markets, and sanitation areas, are perceived as more likely and of impacts, while perceived severity remains high even for rarely experienced events. Hazard perception is positively related to the perceived likelihood of impacts but shows weaker associations with perceived severity. Measured distance also significantly influences hazard perception within domestic environments.

These findings highlight that mazuku risk perception is shaped by collective experience, local environmental knowledge, and the differentiation of everyday spaces. They support the need for risk communication strategies that better connect local understandings with scientific information, particularly by making invisible and dynamic CO₂ hazards more tangible. In the context of rapid urban expansion in Goma and the limited availability of safe land for settlement, relocation strategies are often unrealistic. As a result, in situ mitigation approaches appear more effective than displacement-based strategies. Strengthening continuous monitoring, regularly updating hazard maps, and integrating community-based knowledge into communication approaches are therefore essential to improve risk awareness and support context-sensitive risk reduction in mazuku-prone urban environments.