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L-curves for each inversion are given in Figure 4. A damping parameter of 0.1 gives a good balance between model roughness and fit to the data at all center frequencies. The quality factor, Q, as a function of center frequency in each cell is plotted in Figure 5. A best fit to the median at each frequency is Q, = 500/°°. Our results indicate that the attenuation decreases with increasing of frequency. These results are consistent with the findings of the previous study [1, 2, 5]. Figure 4: L-curve for Qc tomography where the cross is for a damping parameter of 0.1. Each curve is for an inversion at a specific center frequency where the one for 0.75 Hz is noted and the curves decrease for increasing center frequency 0.75, 1.5, 3, 6, and 12 Hz.

Figure 4 L-curves for each inversion are given in Figure 4. A damping parameter of 0.1 gives a good balance between model roughness and fit to the data at all center frequencies. The quality factor, Q, as a function of center frequency in each cell is plotted in Figure 5. A best fit to the median at each frequency is Q, = 500/°°. Our results indicate that the attenuation decreases with increasing of frequency. These results are consistent with the findings of the previous study [1, 2, 5]. Figure 4: L-curve for Qc tomography where the cross is for a damping parameter of 0.1. Each curve is for an inversion at a specific center frequency where the one for 0.75 Hz is noted and the curves decrease for increasing center frequency 0.75, 1.5, 3, 6, and 12 Hz.

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Figure 1: Regional map of Morocco. Triangles are stations (blue ones belongs to WM seismic network and the red ones are the IberArray network), cyan circles are the events [19, 20]. The ellipse witth black color as shown in the figure, is the assumed Q, sensitivity region for a given station and event Where B is the shear-wave speed, R is the epicentral distance, and the foci of the ellipse are the station and event locations. An example of such an ellipse is given in Figure 1. The measurements are made beginning with a lapse time that is two times the S-wave arrival time, ts = R/B, so that the major and minor axes of the ellipse are given by R and V3R/2, respectively.
Figure 1: Regional map of Morocco. Triangles are stations (blue ones belongs to WM seismic network and the red ones are the IberArray network), cyan circles are the events [19, 20]. The ellipse witth black color as shown in the figure, is the assumed Q, sensitivity region for a given station and event Where B is the shear-wave speed, R is the epicentral distance, and the foci of the ellipse are the station and event locations. An example of such an ellipse is given in Figure 1. The measurements are made beginning with a lapse time that is two times the S-wave arrival time, ts = R/B, so that the major and minor axes of the ellipse are given by R and V3R/2, respectively.
Figure 2: The figure shows the vertical component seismogram from the three stations: M006, M011 and PMO8. The first arrow on the left side of the top panel shows origin time and the other two arrows indicate the Coda duration. The lower panels of each station in each set of figures show filtered Coda windows for 5 central frequencies at tgay=2ts. Abbreviations: SN-Signal to noise and C-correlation coefficient. The x axis represents the lapse time windows are restricted at an interval of 30s and the y axis represents amplitude.
Figure 2: The figure shows the vertical component seismogram from the three stations: M006, M011 and PMO8. The first arrow on the left side of the top panel shows origin time and the other two arrows indicate the Coda duration. The lower panels of each station in each set of figures show filtered Coda windows for 5 central frequencies at tgay=2ts. Abbreviations: SN-Signal to noise and C-correlation coefficient. The x axis represents the lapse time windows are restricted at an interval of 30s and the y axis represents amplitude.
a Figure 3: Q. tomograms of Morocco at different center frequencies (given by number in top-left of each panel). The color scale is linear from a minimum q (1000/Q) of 1 to a maximum q given by the number in the top-right of each panel. ae a eee SS eee eS ee eee eee In this study, we have selected 94 local earthquakes recorded with the best signal to noise ratios in 29 seismological stations during the year 2008. All of the stations are equipped with three component broadband sensors. The seismograms used are filtered in five centre frequencies: 0.75, 1.5, 3, 6, 12 Hz. The study is restricted to 30 s. Two different models are used: The Back-projection Tomography method of Xie and Mitchell [17] and the Single Backscattering Aki and Chouet [3]. The results of the attenuation tomography of Coda wave at different center frequencies are given in Figure 3, where only blocks with resolution > 0.95 are shown. The model resolution matrix is obtained from the generalized singular values.
a Figure 3: Q. tomograms of Morocco at different center frequencies (given by number in top-left of each panel). The color scale is linear from a minimum q (1000/Q) of 1 to a maximum q given by the number in the top-right of each panel. ae a eee SS eee eS ee eee eee In this study, we have selected 94 local earthquakes recorded with the best signal to noise ratios in 29 seismological stations during the year 2008. All of the stations are equipped with three component broadband sensors. The seismograms used are filtered in five centre frequencies: 0.75, 1.5, 3, 6, 12 Hz. The study is restricted to 30 s. Two different models are used: The Back-projection Tomography method of Xie and Mitchell [17] and the Single Backscattering Aki and Chouet [3]. The results of the attenuation tomography of Coda wave at different center frequencies are given in Figure 3, where only blocks with resolution > 0.95 are shown. The model resolution matrix is obtained from the generalized singular values.
Figure 5: Boxplot of Q, as a function of frequency at each point in the grid. The best fit to the median Q at each frequenc is given by the dashed line, Q, = 500°”.
Figure 5: Boxplot of Q, as a function of frequency at each point in the grid. The best fit to the median Q at each frequenc is given by the dashed line, Q, = 500°”.
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