example Fourier spectra

Generate the Fourier spectra of an earthquake suite using OpenSeismoMatlab

Contents

Input

earthquake motions

eqmotions={'Imperial Valley'; % Imperial valley 1979
    'Kocaeli';
    'Loma Prieta';
    'Northridge';
    'San Fernando';
    'Spitak';
    'Cape Mendocino';
    'ChiChi';
    'elcentro_NS_trunc'; % Imperial valley 1940
    'Hollister';
    'Kobe'};

Switch

sw='fas';

Extract fourier spectra

Initialize cell of Fourier spectra

Fourier=cell(numel(eqmotions),1);
% Calculation of Fourier spectra
for i=1:numel(eqmotions)
    % earthquake
    data=load([eqmotions{i},'.dat']);
    t=data(:,1);
    dt=t(2)-t(1);
    xgtt=data(:,2);
    S=OpenSeismoMatlab(dt,xgtt,sw);
    Fourier{i}=[S.freq,S.FAS];
end

Output

Plot Fourier amplitude

Fig1 = figure('units', 'centimeters', 'Position', [0,0, 20/sqrt(2), 20]);
% Scan all subplots
for i=1:numel(eqmotions)
    subplot(4,3,i)
    plot(Fourier{i}(:,1),Fourier{i}(:,2),'k','LineWidth',1);
    set(gca,'FontName','Times New Roman')
    title(eqmotions{i},'FontName','Times New Roman')
    ylabel('fas','FontName','Times New Roman')
    xlabel('Frequency (Hz)','FontName','Times New Roman')
    axis tight
end
drawnow;
pause(0.1)

Copyright

Copyright (c) 2018-2023 by George Papazafeiropoulos

Published with MATLAB® R2022b