scholarly journals ESTIMATION OF SEISMIC DISPLACEMENT FROM STRONG MOTION ACCELERATION RECORD BY ELIMINATING STEP FUNCTION COMPONENT

2020 ◽  
Vol 85 (767) ◽  
pp. 29-37
Author(s):  
Misa MORIWAKI ◽  
Takashi HIRAI ◽  
Nobuo FUKUWA
Keyword(s):  
Strong Motion ◽  
Step Function ◽  
Seismic Displacement ◽  
Acceleration Record

scholarly journals Calculation of response spectra from strong-motion earthquake records

1969 ◽  
Vol 59 (2) ◽  
pp. 909-922
Author(s):  
Navin C. Nigam ◽  
Paul C. Jennings
Keyword(s):  
Computing Time ◽  
Strong Motion ◽  
Response Spectra ◽  
Kutta Method ◽  
Third Order ◽  
Earthquake Records ◽  
Runge Kutta Method ◽  
Governing Differential Equation ◽  
Comparable Accuracy ◽  
Acceleration Record

abstract A numerical method for computing response spectra from strong-motion earthquake records is developed, based on the exact solution to the governing differential equation. The method gives a three to four-fold saving in computing time compared to a third order Runge-Kutta method of comparable accuracy. An analysis also is made of the errors introduced at various stages in the calculation of spectra so that allowable errors can be prescribed for the numerical integration. Using the proposed method of computing or other methods of comparable accuracy, example calculations show that the errors introduced by the numerical procedures are much less than the errors inherent in the digitization of the acceleration record.

scholarly journals Rupture imaging for the 2016 August 24, Mw=6.0 central Italy earthquake, from back-projection of strong-motion array data

2016 ◽  
Vol 59 ◽  
Author(s):  
Gilberto Saccorotti ◽  
Davide Piccinini ◽  
Carlo Giunchi
Keyword(s):  
Waveform Inversion ◽  
Central Italy ◽  
Strong Motion ◽  
Surface Damage ◽  
Beam Power ◽  
Rupture Propagation ◽  
Fault Surface ◽  
Seismic Displacement ◽  
Motion Data ◽  
Central Italy Earthquake

<p class="western" align="justify"><span style="font-family: 'Bitstream Charter', serif;"><span>By extending the conventional Beam-Forming frequency-wavenumber power spectral estimate to the case of arbitrarily-shaped wavefronts, we obtained images of rupture propagation during the 2016 August 24, Mw=6.0 central Italy earthquake. Using a set of strong-motion accelerometers, we evaluate the beam power along the travel time curves associated with synthetic sources spanning a model fault surface. This allows deriving time-dependent images of the distribution of energy radiation throughout the fault plane. Results indicate bi-lateral rupture propagation toward SE and NW, in rough agreement with surface co-seismic displacement and surface damage pattern. To a first order, our results are also consistent with those obtained from full-waveform inversion of strong-motion data.</span></span></p>

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.

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
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