Figure 7. Quality factor Q_p (dotted lines and gray bars), Q_s (thin lines and black bars), and geometrical spreading n versus frequency for distance from 10 to 38 km (left frames) and from 60 to 80 km (right frames). The mean ±2 are shown. For P waves, the results for frequencies smaller than 2 Hz (gray shaded area) are not reliable due to the low signal-to-noise ratio. In the left panel, results of fit (thick lines for Q_S and gray lines for Q_P) are shown.