The rural slopes of Mount Merapi in Yogyakarta Province, Indonesia, existed as vulnerable areas due to recurrent eruptions every few years, necessitating improved strategies to enhance local resilience to volcanic disasters. This study investigates community engagement in fostering disaster preparedness in the Kepuharjo and Umbulharjo, the most vulnerable villages of Merapi slopes in the Cangkringan District of Sleman Regency. Utilizing a qualitative field method, data was collected through on-site observations, document studies, interviews with 14 purposive informants, and FGDs with 21 local voluntary and related stakeholder members. The findings reveal that structural and cognitive social capital mutually reinforce disaster preparedness capacity. The structural dimension evolved with the initiative of resilient village programs, subsequently reinforced by the villagers' engagement in local mitigation actions such as developing volunteer groups, village contingency plans, and diverse communal work for risk prevention. This structural existence was intertwined with the cognitive dimension, referring to the preserved traditional values and beliefs that maintain collective norms and collaboration culture. The finding implies the significance of encouraging structural and cognitive approaches in developing policies to strengthen community-based disaster resilience and, in the theoretical insights, broadening the social capital lens in social studies of disaster.