THE EMPIRICAL GREEN’S FUNCTION TECHNIQUE MODIFICATION FOR ACCELEROGRAM SYNTHESIS IN LOWSEISMICITY REGIONS

2018 ◽  
Vol 12 (5-6) ◽  
pp. 72-80
Author(s):  
A. A. Krylov
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Main Shock ◽  
Amplitude Spectrum ◽  
Strong Motion ◽  
Function Technique ◽  
Focal Region ◽  
Empirical Green’S Function ◽  
Epicentral Zone ◽  
Empirical Green's Function

In the absence of strong motion records at the future construction sites, different theoretical and semi-empirical approaches are used to estimate the initial seismic vibrations of the soil. If there are records of weak earthquakes on the site and the parameters of the fault that generates the calculated earthquake are known, then the empirical Green’s function can be used. Initially, the empirical Green’s function method in the formulation of Irikura was applied for main shock record modelling using its aftershocks under the following conditions: the magnitude of the weak event is only 1–2 units smaller than the magnitude of the main shock; the focus of the weak event is localized in the focal region of a strong event, hearth, and it should be the same for both events. However, short-termed local instrumental seismological investigation, especially on seafloor, results usually with weak microearthquakes recordings. The magnitude of the observed micro-earthquakes is much lower than of the modeling event (more than 2). To test whether the method of the empirical Green’s function can be applied under these conditions, the accelerograms of the main shock of the earthquake in L'Aquila (6.04.09) with a magnitude Mw = 6.3 were modelled. The microearthquake with ML = 3,3 (21.05.2011) and unknown origin mechanism located in mainshock’s epicentral zone was used as the empirical Green’s function. It was concluded that the empirical Green’s function is to be preprocessed. The complex Fourier spectrum smoothing by moving average was suggested. After the smoothing the inverses Fourier transform results with new Green’s function. Thus, not only the amplitude spectrum is smoothed out, but also the phase spectrum. After such preliminary processing, the spectra of the calculated accelerograms and recorded correspond to each other much better. The modelling demonstrate good results within frequency range 0,1–10 Hz, considered usually for engineering seismological studies.

Catalogue of U.S. Geological Survey strong-motion records, 1993

Circular ◽  
1995 ◽  
Author(s):  
J. C. Switzer ◽  
R.L. Porcella
Keyword(s):  
Strong Motion ◽  
Geological Survey ◽  
Strong Motion Records

U.S. Geological Survey National Strong-Motion Project strategic plan, 2017–22

2017 ◽  
Author(s):  
Brad T. Aagaard ◽  
Mehmet Celebi ◽  
Lind Gee ◽  
Robert Graves ◽  
Kishor Jaiswal ◽  
...  
Keyword(s):  
Strong Motion ◽  
Strategic Plan ◽  
Geological Survey

Strong-motion seismograph station listing

1973 ◽  
Author(s):  
Virgilio Perez ◽  
S.C. Schwartz
Keyword(s):  
Strong Motion ◽  
Seismograph Station

Strong-motion earthquake accelerograms digitization and analysis

1978 ◽  
Author(s):  
A. Gerald Brady ◽  
Virgilio Perez
Keyword(s):  
Strong Motion ◽  
Earthquake Accelerograms
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