Relationship between seismicity and water level in the Enguri high dam area (Georgia) using the singular spectrum analysis

Abstract

Abstract. The declustered seismic catalog from 1965 to 2010 around the Enguri high dam reservoir in western Georgia was analyzed using the singular spectrum analysis (SSA) technique in order to investigate the relationship of local seismicity with the reservoir water variations. In particular, the seismic activity was analyzed in two periods: a "reference" period, from 1965 to 1970, before the start of dam building in 1971; and an "active" period, from 1978 to 2010, in which the influence of the reservoir was significantly effective on the seismic activity (since the first flooding of the dam occurred in 1978). The SSA was applied to both the monthly number of earthquakes and the time series of the monthly mean of the water level. The first four reconstructed components explained most of the total variance in both seismicity and water level. Clear signatures of the annual oscillation linked with the loading/unloading operations of the dam are present in the periodogram of the second and the third reconstructed components of the seismic activity during the "active" period. Such annual cycle is absent in the periodogram of the reconstructed components of the seismic activity during the "reference" period. This is a clear indication of the reservoir-induced character of the seismicity around the Enguri dam.

Nonlinear Dynamics of Seismicity and Fault Zone Dynamics Around Large Dams: The Case of Enguri Dam, Caucasus

“…Thus, in the last period, beginning from the period 1985-1986, the dynamics of local seismicity, especially, waiting times is much more ordered due probably to synchronization of seismic activity with the regular pattern of WL variation. This conclusion is confirmed by our earlier work where we carried out analysis of Enguri area seismic activity using the singular spectrum analysis (SSA) technique in order to investigate the relationship of local seismicity with the reservoir water variations [12][13][14][15]. We revealed the dominant one-year period in seismicity, which corresponds to seasonal load-unload of the Enguri dam lake; this period was absent in ETS of the area in the reference period before lake impoundment.…”

“…Earlier several studies were devoted to complexity analysis of seismic regime in the Enguri dam area, namely to variation of the phase diffusion coefficient of phase differences between daily released seismic energy and water level daily variations [12,13], Visibility Graph Analysis [14], and Singular Spectrum Analysis [15]. In the present paper we analyze recurrent patterns of local seismicity, using such methods as recurrence plots, detrended fluctuation analysis, and Lempel and Ziv complexity measure.…”

“…Method of DFA permits the detection of long-range correlations embedded in a nonstationary time series through calculation of a quantitative parameter-DFA scaling exponent. This analysis technique is widely accepted and often used for different types of time series including geophysical data sets [14,15].…”

Analysis of the cross-correlation between water level and seismicity at Açu reservoir (Brazil)

“…On the other hand, the correlation between elements of the hydrological cycle and seismic data was performed in only a few papers, where the details of the reservoir-induced seismicity using more robust signal processing techniques are investigated (Peinke et al, 2006;Telesca, 2010Telesca, , 2011Telesca et al, 2012aTelesca et al, , 2012bTelesca et al, , 2012c.…”

A Hybrid Short-Term Power Load Forecasting Model Based on the Singular Spectrum Analysis and Autoregressive Model

“…Then, some of these components are used for time series forecasting. At present, the SSA method has been widely applied to cope with the problem in many domains such as geography and sociology [16,17].…”