scholarly journals Strong Motion Simulation of the 1987 Chiba-ken-toho-oki Earthquake (MJ6.7) Using Stochastic Green's Function Generation Method Empirically Considering Surface Waves and Scattering Waves

2015 ◽  
Vol 15 (7) ◽  
pp. 7_34-7_48
Author(s):  
Toshimi SATOH
Keyword(s):  
Green’S Function ◽  
Surface Waves ◽  
Green's Function ◽  
Strong Motion ◽  
Motion Simulation ◽  
Function Generation ◽  
Strong Motion Simulation

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.

scholarly journals BROADBAND STRONG MOTION SIMULATION OF THE GREAT 1923 KANTO EARTHQUAKE IN THE TOKYO METROPOLITAN AREA

2007 ◽  
Vol 13 (26) ◽  
pp. 447-450 ◽  
Author(s):  
Shinichi MATSUSHIMA ◽  
Motofumi WATANABE ◽  
Kazuo DAN ◽  
Toshiaki SATO ◽  
Jun'ichi MIYAKOSHI
Keyword(s):  
Metropolitan Area ◽  
Strong Motion ◽  
Motion Simulation ◽  
Tokyo Metropolitan ◽  
Tokyo Metropolitan Area ◽  
Kanto Earthquake ◽  
Strong Motion Simulation

Study on long-period strong motion simulation for large-scale earthquakes

2007 ◽  
Vol 4 (3) ◽  
pp. 301-307 ◽  
Author(s):  
Boming Zhao ◽  
Takao Kagawa ◽  
Masato Turugi
Keyword(s):  
Large Scale ◽  
Strong Motion ◽  
Motion Simulation ◽  
Long Period ◽  
Strong Motion Simulation

The Search of Diffusive Properties in Ambient Seismic Noise

2021 ◽  
Author(s):  
José Piña-Flores ◽  
Martín Cárdenas-Soto ◽  
Antonio García-Jerez ◽  
Michel Campillo ◽  
Francisco J. Sánchez-Sesma
Keyword(s):  
Green’S Function ◽  
Surface Waves ◽  
Green's Function ◽  
Seismic Noise ◽  
Elastic Field ◽  
Spectral Ratio ◽  
Ambient Seismic Noise ◽  
Data Sets ◽  
Original Experiment ◽  
Imaging Theory

ABSTRACT Ambient seismic noise (ASN) is becoming of interest for geophysical exploration and engineering seismology, because it is possible to exploit its potential for imaging. Theory asserts that the Green’s function can be retrieved from correlations within a diffuse field. Surface waves are the most conspicuous part of Green’s function in layered media. Thus, the velocities of surface waves can be obtained from ASN if the wavefield is diffuse. There is widespread interest in the conditions of emergence and properties of diffuse fields. In the applications, useful approximations of the Green’s function can be obtained from cross correlations of recorded motions of ASN. An elastic field is diffuse if the background illumination is azimuthally uniform and equipartitioned. It happens with the coda waves in earthquakes and has been verified in carefully planned experiments. For one of these data sets, the 1999 Chilpancingo (Mexico) experiment, there are some records of earthquake pre-events that undoubtedly are composed of ASN, so that the processing for coda can be tested on them. We decompose the ASN energies and study their equilibration. The scheme is inspired by the original experiment and uses the ASN recorded in an L-shaped array that allows the computation of spatial derivatives. It requires care in establishing the appropriate ranges for measuring parameters. In this search for robust indicators of diffusivity, we are led to establish that under certain circumstances, the S and P energy equilibration is a process that anticipates the diffusion regime (not necessarily isotropy), which justifies the use of horizontal-to-vertical spectral ratio in the context of diffuse-field theory.

Strong Motion Simulation of the Weihe Basin in Wenchuan Earthquake

2014 ◽  
Vol 501-504 ◽  
pp. 1460-1463
Author(s):  
Qi Fang Liu
Keyword(s):  
Wenchuan Earthquake ◽  
Spectral Element Method ◽  
Numerical Technique ◽  
Strong Motion ◽  
Spectral Element ◽  
Motion Simulation ◽  
Computing Technique ◽  
5.12 Wenchuan Earthquake ◽  
Weihe Basin ◽  
Strong Motion Simulation

Seismic response of the Weihe basin generated by 5.12 Wenchuan earthquake is simulated by using the spectral-element method and parallel computing technique, considering 3D basin model incorporated with real topography. The wave propagation and the comparison of the synthetic and observed records are studied in detail in this paper. The result shows that appropriate source and detailed basin model and accurate numerical technique can simulate the wavefield and large basin ground motion well.

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