Erratum

In the original version of this article (Villalobos-Escobar and Castro 2014), Figures 6, 7, and 8 were marked up incorrectly. Figure 6 should show examples of nonparametric attenuation functions, instead the incorrect Figure 6 shows values of the exponent b of the geometrical spreading function (equation 4) and estimates of the quality factor Q. Figure 7 should show attenuation functions scaled according to event 9 (Table 1) which is an M = 3.5 earthquake. Instead, the incorrect Figure 7 printed shows estimates of Q obtained by other authors and those obtained in this study. Figure 8 is also incorrect; this figure should show the values of b and Q displayed in the printed Figure 6.

In this erratum, the corrected Figures 6, 7, and 8 are shown as Figure 1, Figure 2, and Figure 3, respectively.

Figure 1
figure 1

Examples of nonparametric attenuation functions obtained for 10 different frequencies. Black circles are observed horizontal S-wave spectral amplitudes for all magnitudes, open circles are observed vertical S-wave spectral amplitudes for all magnitudes. Black continuous line corresponds to the attenuation function found for the horizontal spectral amplitudes (cm/s2) and dashed line corresponds to the attenuation function found for the vertical component of the acceleration spectral amplitudes (cm/s2). This is the corrected Figure 6 in Villalobos-Escobar and Castro (2014).

Figure 2
figure 2

Attenuation functions obtained for event 9 ( M L =3.5) for 10 of the 23 frequencies studied. The dots are the observed horizontal spectral amplitudes of event 9, continuous line represents the un-scaled attenuation function and the dashed line represents the attenuation function scaled by its respective source-size factor. This is the corrected Figure 7 in Villalobos-Escobar and Castro (2014).

Figure 3
figure 3

Estimates of b (left frame) and Q (right frame) for N = 1.0 (see equation (4)) for the whole hypocentral distance range (10-140km). This is the corrected Figure 8 in Villalobos-Escobar and Castro (2014).