Trigger Mechanisms of Gas Hydrate Decomposition, Methane Emissions, and Glacier Breakups in Polar Regions as a Result of Tectonic Wave DeformationстатьяИсследовательская статья
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Аннотация:Trigger mechanisms are proposed for gas hydrate decomposition, methane emissions,and glacier collapse in polar regions. These mechanisms are due to tectonic deformation waves inthe lithosphere–asthenosphere system, caused by large earthquakes in subduction zones, locatednear the polar regions: the Aleutian arc, closest to the Arctic, and the Antarctica–Chilean and Tonga–Kermadec–Macquarie subduction zones. Disturbances of the lithosphere are transmitted over longdistances (of the order of 2000–3000 km and more) at a speed of about 100 km/year. Additionalstresses associated with them come to the Arctic and Antarctica several decades after the occurrenceof seismic events. On the Arctic shelf, additional stresses destroy the microstructure of metastablegas hydrates located in frozen rocks at shallow depths, releasing the methane trapped in them andleading to filtration and emissions. In West Antarctica, these wave stresses lead to decreases in theadhesions of the covered glaciers with underlying bedrock, sharp accelerations of their sliding intothe sea, and fault occurrences, reducing pressure on the underlying rocks containing gas hydrates,which leads to their decomposition and methane emissions.
