Anomalous Gas Volcanism in the Black Sea

In the Black Sea, an unprecedented intensity of gas discharge of the seabed in the form of jet emissions (gas seeps, torches, flares) and fountains of gas emissions from mud volcanoes have been established, which are described in detail in the monograph. However, the main attention is paid to anomalous single-stage methane emissions as a result of the famous Yalta earthquakes of 1927, accompanied by amazing and mysterious fiery phenomena. An analysis of the available geological and geophysical materials indicates that the fire phenomena were caused by massive methane emissions as a result of a powerful mantle gas-fluid flow into decompaction zones of the crystalline basement along tectonic faults of various scales within the Odessa-Sinop and Circum-Black Sea fault zones. Earthquakes served as a trigger for the activation of tectonic disturbances in the near-bottom sedimentary horizons for the migration of focused deep gas-fluid flows. The deep structure of the source zones and the nature of the seismic process are analyzed, the nature of the manifestations of fire phenomena is assessed. The enormous volumes of gas emissions are noted – millions of cubic meters of methane, which are proposed as a kind of gas plume, the nature of which is associated with zones of deep faults in the upper mantle. Using the geological and geophysical materials obtained in recent years, the authors significantly refined the structural-tectonic construction and localization of gas-mud activity in the Black Sea water area. All these new materials, along with an analysis of the available data on the seismicity of the Crimean region, open up the possibility of explaining the fiery phenomena that were observed during the Yalta earthquakes of 1927 and facilitate the interpretation and understanding of their nature.