Earthquakes are among the most energetic natural processes shaping Earth’s surface, with the potential to trigger or enhance methane emissions from marine sediments. Such events influence local biogeochemical cycles and contribute to the global methane budget, which remains poorly constrained. The SEEPMAR project (Seismic Events and methane seEP dynamics in the Sea of MARmara) aims to determine how recent seismic activity, particularly the April 2025 Mw 6.2 earthquake, modulates seafloor methane emissions and their fate within the water column in the Sea of Marmara. Three objectives will guide the study: (1) Assess changes in gas emission distribution following recent seismicity; (2) Monitor short-term variations in methane and related parameters using a temporary seafloor observatory; (3) Track methane concentration and microbial community response in the water column. The cruise aboard the R/V TÜBİTAK Marmara will combine AUV-based acoustic mapping, and CTD profiling. By linking seismic activity to methane flux variability and microbial response, SEEPMAR will advance our understanding of tectonically driven carbon cycling and its potential feedbacks on oceanic systems.