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For the past 50 years, gas hydrates have been regarded by scientists as part of the hydrocarbon reserves, particularly at governmental institutions. A better understanding of the processes controlling the distribution and dynamics of gas hydrates in nature, especially their sensitivity to changes in gas composition, pressure and temperature, requires both theoretical knowledge of their stability and dynamic behavior and knowledge of how gas hydrates form and where they occur in the sediment. Geophysical data, geochemical data and thermodynamic models indicate that both the rate of response and the total integrated response to climate change in the ocean depend on the location and forms in which hydrates are distributed. Thus, mapping gas hydrates by indirect geophysical methods or through dedicated drilling campaigns is fundamental to all research involving gas hydrates. This includes studies of their role in climate change, their consequences for slope stability, their role at the base of the food web for benthic ecosystems and their potential as a future energy resource. Here we provide a brief introduction to the occurrence of gas hydrates on Earth, and how this information may assist in detecting them on other planetary bodies.

Neotectonic Interpretation of the different marine surveys (ACT, …) swath bathymetry and different onshore-offshore sismic profiles combined to classical structural fieldwork, geodetic, seismological and interferometric studies lead us to propose a global structural scheme and confirm the regional escape tectonics affecting both onshore-offshore of SW Taiwan. First, it is highlighted here the difficulty to only interprete the swath bathymetry even in the northern tip of the Manila accretionnary prism which is a rather simple geological context but affected by both (1) a strong amount of sedimentation due to the Taiwan mountain belt erosion, and (2) to the submarine erosion of the giant Penghu canyon. Second point, is the importance of the seismic interpretation in order to get the offshore bedding and structural data combined with the swath bathymetry and to the photointerpretation of the digital Terrain Model combined to the accurate geological maps to precisely delineate the blocks that is inferred to be submitted to a classical escape tectonic. Third, the precise study of the two new major structural boundaries Fangliao and Young-An structures which guides the SW Taiwan extrusion. Combined with onshore studies (e.g. interferometry (DINSAR), geodetic, seismology and field work) which gives (1) locations, characterization and quantification on the interseismic displacements and (2) lead us to modify our view of the global tectonic structures of the SW Taiwan. To conclude, it is highly recommended to combine both approach on and offshore geology in order to better understand geology and active structures in that part of the world.