| Abstrakt: |
The characteristics of the attenuation of seismic coda waves in the Fergana Basin are studied. The study analyzes short-period coda waves of local earthquakes recorded by frequency-selective seismic stations in 1960–1984 and digital seismograms of more than 100 earthquakes that occurred in the Fergana Basin from 2005 to 2021 and were recorded by the stations of the KNET network. Detailed analysis of variations in the attenuation field within the Fergana Basin showed that it is characterized by a mosaic structure that changes with depth. This attenuation field structure is consistent with the structure of the velocity field obtained by seismic tomography, as well as with the conclusions drawn from analysis of the density model. The features of the seismicity distribution relative to the position of blocks and weakened zones at different depths are considered. The correlation between contrasting objects of the attenuation field in the Fergana Basin and objects in the pre-Mesozoic strata of contrasting petrophysical characteristics has been revealed. Oil and gas fields in the Fergana Basin are associated with zones of strong attenuation, which are probably conduits for migration of fluids, including hydrocarbons. A possible explanation is also considered for the increased sensitivity of the atmospheric baric field near the Namangan hydrometeorological station to processes associated with preparation and occurrence of significant seismic events here. [ABSTRACT FROM AUTHOR] |
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