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

2012 ◽  
Vol 12 (8) ◽  
pp. 2479-2485 ◽  
Author(s):  
L. Telesca ◽  
T. Matcharasvili ◽  
T. Chelidze ◽  
N. Zhukova
Keyword(s):  
Water Level ◽  
Spectrum Analysis ◽  
Seismic Activity ◽  
Singular Spectrum Analysis ◽  
Reference Period ◽  
Active Period ◽  
Reservoir Water ◽  
Singular Spectrum ◽  
Dam Building ◽  
Relationship Of

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.

scholarly journals Multi-Channel Singular Spectrum Analysis on Geocenter Motion and Its Precise Prediction

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1403
Author(s):  
Xin Jin ◽  
Xin Liu ◽  
Jinyun Guo ◽  
Yi Shen
Keyword(s):  
Solid Earth ◽  
Spectrum Analysis ◽  
Mean Squared Error ◽  
Moving Average ◽  
Singular Spectrum Analysis ◽  
Singular Spectrum ◽  
Autoregressive Moving Average Model ◽  
Seasonal Characteristics ◽  
Geocenter Motion ◽  
Moving Average Model

Geocenter is the center of the mass of the Earth system including the solid Earth, ocean, and atmosphere. The time-varying characteristics of geocenter motion (GCM) reflect the redistribution of the Earth’s mass and the interaction between solid Earth and mass loading. Multi-channel singular spectrum analysis (MSSA) was introduced to analyze the GCM products determined from satellite laser ranging data released by the Center for Space Research through January 1993 to February 2017 for extracting the periods and the long-term trend of GCM. The results show that the GCM has obvious seasonal characteristics of the annual, semiannual, quasi-0.6-year, and quasi-1.5-year in the X, Y, and Z directions, the annual characteristics make great domination, and its amplitudes are 1.7, 2.8, and 4.4 mm, respectively. It also shows long-period terms of 6.09 years as well as the non-linear trends of 0.05, 0.04, and –0.10 mm/yr in the three directions, respectively. To obtain real-time GCM parameters, the MSSA method combining a linear model (LM) and autoregressive moving average model (ARMA) was applied to predict GCM for 2 years into the future. The precision of predictions made using the proposed model was evaluated by the root mean squared error (RMSE). The results show that the proposed method can effectively predict GCM parameters, and the prediction precision in the three directions is 1.53, 1.08, and 3.46 mm, respectively.

Application of singular spectrum analysis in reconstruction of the annual signal from GRACE

2020 ◽  
Vol 14 (3) ◽  
pp. 295-302
Author(s):  
Chuandong Zhu ◽  
Wei Zhan ◽  
Jinzhao Liu ◽  
Ming Chen
Keyword(s):  
Time Series ◽  
Spectrum Analysis ◽  
Singular Spectrum Analysis ◽  
Mixture Effect ◽  
Singular Spectrum ◽  
Grace Data ◽  
Terrestrial Water ◽  
Annual Signal ◽  
Long Term Variations

AbstractThe mixture effect of the long-term variations is a main challenge in single channel singular spectrum analysis (SSA) for the reconstruction of the annual signal from GRACE data. In this paper, a nonlinear long-term variations deduction method is used to improve the accuracy of annual signal reconstructed from GRACE data using SSA. Our method can identify and eliminate the nonlinear long-term variations of the equivalent water height time series recovered from GRACE. Therefore the mixture effect of the long-term variations can be avoided in the annual modes of SSA. For the global terrestrial water recovered from GRACE, the peak to peak value of the annual signal is between 1.4 cm and 126.9 cm, with an average of 11.7 cm. After the long-term and the annual term have been deducted, the standard deviation of residual time series is between 0.9 cm and 9.9 cm, with an average of 2.1 cm. Compared with the traditional least squares fitting method, our method can reflect the dynamic change of the annual signal in global terrestrial water, more accurately with an uncertainty of between 0.3 cm and 2.9 cm.

Sign in / Sign up

Export Citation Format

Share Document