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Nonlinear Dynamics of seismicity and fault zone strain around large dam: the case of Enguri dam, Caucasus.
1  Institute of Geophysics, Alexidze str. 1. 0160,Tbilisi, Georgia


Monitoring of seismic activity in the area of large dam is a unique tool for understanding the intimate connections between earthquakes generation and man-made regular quasi-periodic strains in the Earth, created by seasonal water load-unload in the reservoir. We can consider large dams’ area as a large natural laboratory, providing possibility of studying seismic process in almost controlled (repeated) conditions. The 271 m high Enguri arc dam was built in the canyon of Enguri river in West Georgia. It is located in a zone of high seismicity (M7.5). The water level high in the lake varies seasonally by 100 m, which means that Enguri reservoir can activate Reservoir-Triggered Seismicity (RTS). Due to a high seismic activity of the region, the seismic station’s network was installed in the area of Enguri dam well before its construction with the aim of studying possible reservoir-triggered activity. The RTS pattern in the Enguri area should depend on the Water Level (WL) variation regime in the lake. The main goal of the paper is to apply new methods of complexity analysis (DFA, RQA and LZC) in order to assess in a quantitative way the correlation between WL variations and local seismicity and assess the impact of man-made activity on the local seismicity pattern.

Keywords: seismicity ; large dam