Mitigating <i>Mazuku</i> hazards: implementation and effectiveness of local dry-gas degassing measures in the Goma area (Virunga Volcanic Province)

Abstract. Mitigation of carbon dioxide diffuse degassing hazards remains underexplored in comparison to other volcanic hazards such as eruptions, despite their persistent and deadly impacts on communities living in active volcanic regions. This study uses a mixed-methods approach – combining quantitative surveys and qualitative interviews – to assess household perceptions of the implementation and effectiveness of risk mitigation measures against mazuku, a locally known hazard caused by emissions of carbon dioxide in the western part of Goma, Virunga Volcanic Province. Data were collected across three sampling zones, capturing demographic characteristics, eruption risk experiences, and perceptions regarding the implementation of mazuku risk mitigation measures. Findings reveal three locally recognised categories of mitigation measures: (1) emission-limiting measures, such as blocking gas with waste materials; (2) adaptive measures, such as house ventilation or living on upper floors; and (3) awareness measures based on orally transmitted local knowledge such as avoiding mazuku zone early morning. Financial resources, gender and prior risk experience – often linked to length of residence – emerged as significant positive determinants of both motivation and perceived efficacy for the first two categories. Perceptions of awareness measures showed no significant variation across zones even between demographic profile groups. Spatial patterns in perceived implementation and perceived efficacy appear to reflect collective community mitigation implementation rather than based on individual risk mitigation assessment, with some measures perceived as effective despite limited physical evidence of reduced gas concentration. The study supports the importance of co-creating mitigation strategies with local communities, adapting interventions to socio-economic realities and avoiding the importation of external mitigation measures that may lack contextual relevance. It also calls for complementary research measuring the actual effectiveness of these measures through physical monitoring of mazuku concentrations. These insights, grounded in a Global South context – characterised by rapid uncontrolled urbanisation, offer a valuable perspective for the development of inclusive and effective strategies of carbon dioxide diffuse degassing risk management.