Temporal Evolution of Microseismicity in Response to Reservoir Operation at the Enguri Dam (Georgia)
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Abstract
In this study, we analyze the temporal evolution of microseismicity near the Enguri Dam (Georgia) using over four years of data from a local seismic network installed under the DAMAST project. A detailed completeness analysis identifies a conservative threshold of Mc = 0.6 within 17 km of the dam, enabling robust estimation of Gutenberg–Richter parameters. Elevated b-values in the local catalog—compared to national Mw-based data—suggest a significant reservoir-induced component. Extending the analysis to a 30 km radius, we find that the completeness threshold increases to Mc = 1.0; however, the b-value remains high (≥ 1) when estimated using the Maximum Likelihood method. This spatial consistency in elevated b-values indicates that reservoir operations influence seismicity up to at least 30 km from the dam. Seismicity correlates with water level changes, especially during filling and drawdown phases, while meteorological variables show no consistent relationship. Our findings highlight the influence of reservoir operations on microseismic activity and underscore the value of integrated hydrological and seismological monitoring in dam regions.
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