16:30 〜 16:45
[AOS12-10] Characterizing active faults and seafloor geomorphological features in the UAE’s Eastern Offshore, Gulf of Oman
キーワード：pockmarks, gas seeps, multibeam, echosounding, seismic, Gulf of Oman
The eastern offshore region of the United Arab Emirates is located along the northeastern boundary of the Arabian Plate in the Gulf of Oman. Recent discoveries of gas seeps and pockmarks along this margin suggest a significant carbon flux into the Arabian Sea and atmosphere. The active faulting behavior and its relation to regional tectonics remain less understood. Additionally, detailed statistical analyses of the pockmarks and the volumes of gases released have not been explored. This study addresses these gaps using newly acquired high-resolution multibeam bathymetry, wideband echosounding, seismic reflection profiles, and earthquake data. The study identifies N-S to NNW-SSE fault lineaments; some correspond to shallow and low-magnitude earthquakes. These faults penetrate up to 3 km deep, cutting through Holocene to Miocene sequences. Active seeps are detected through wideband echosounding, while semiautomated picking identifies the number, diameters, depths, and trends of the pockmarks. The volumes of circular pockmarks are calculated, and for pockmarks eroded by bottom currents (e.g., crescent-shaped and elongated ones), initial volumes are estimated based on the smallest circular pockmarks, representing the most recent formations. Distribution of the thick Pleistocene-Holocene deposits and fault geometries (e.g., negative flower structures and en-echelon half-grabens) indicates eastward tilting and a localized pull-apart basin. These features are linked to the tectonic activity of the Makran subduction and the Zendan-Minab strike-slip faulting. The total volume of all pockmarks provides an estimate of the gases released into the sea, thereby assessing the contribution of this pockmark field to the global carbon reservoir and present/paleo-climate changes.