Geophysical evidence for submarine methane seepage on the Western slope of Okinawa Trough

Identifying seafloor methane seepage efficiently has important implications for assessing environmental impact, reducing the uncertainty of top seal integrity, understanding petroleum system, and mitigating drilling hazards due to shallow gas influx. Pore water geochemistry analyses suggest that study area an extremely high flux active anaerobic oxidation processes. However, geochemical data cannot provide details about internal seepages. The geophysical dataset from Western slope Okinawa Trough, including 2D high-resolution seismic, sub-bottom profiles, bathymetry, gives us a good opportunity understand detailed characteristics seepages in this study. Geophysical have revealed numerous seepage-related features such as seismic chimneys, pockmarks, submarine domes, amplitude anomalies, bright spots enhanced reflections. Pockmarks domes are often associated with indicating fluid migration is their formation. various expressions may represent different stages seepage. Fluid quickly drains, causing severe sediment deformation forming whereas indicate early discharge. Chimneys do not extend venting gradual focused. Flares linked or pockmarks active. Several factors triggered existence on tectonic setting, overpressure rapid sedimentation.