Seismic Characteristics of Gas Accumulations in Sediments of Lake Balaton, Hungary

High-resolution water seismic investigations are often limited by the presence of shallow gas in marine and lacustrine environments. Lake Balaton, Hungary is no exception. Gas is a major obstacle for deeper stratigraphic mapping but also an important indicator of ecological and geological processes, hence it deserves a detailed study. This work, applying single- and multichannel profiles from the last 3 decades from the area of Lake Balaton, presents data about the general shallow gas characteristics of this lacustrine environment. Various anomaly types have been observed that were grouped into 3 distinct (upper, middle and lower mud) gas fronts that are sometimes superimposed on each other. The specific gas fronts are showing different origin and temporal behavior. We have concluded that the most important sources of the gas are the biodegradation of recently deposited organic matter including anthropogenic pollution, gas upwelling helped by tectonically amplified groundwater discharge and the decomposition of Pleistocene peat.