Analysis of the relationship between water level temporal changes and seismicity in the Mingechevir reservoir (Azerbaijan)

The temporal variations of the instrumental seismicity (0.5 <= M-L <= 3.5) recorded in the Mingechevir area (Azerbaijan) between January 2010 to December 2018 and its relationship with the level variation of the water reservoir was analysed in this study. The monthly number of events was analysed by using the correlogram-based periodogram, the singular spectrum analysis (SSA) and the empirical mode decomposition (EMD), which are robust against the short size of the time series. Our results point out to the following findings: (1) quasi-annual periodicity was found in one SSA reconstructed component of the monthly number of events; (2) quasi-annual periodicity was found in one EMD intrinsic mode function of the monthly number of earthquakes. These obtained results could support in a rigorously statistical manner that the seismicity occurring in Mingechevir area could be triggered by the yearly cycle of the water level of the reservoir.