D.E. McNamara
2000
The characteristics of seismic energy attenuation are determined using high frequency <i>Lg</i> waves from 27 crustal earthquakes, in south-central Alaska. <i>Lg</i> time-domain amplitudes are measured in five pass-bands and inverted to determine a frequency-dependent quality factor, Q(<i>f</i>), model for south-central Alaska. The inversion in this study yields the frequency-dependent quality factor, in the form of a power law: Q(<i>f</i>) = Q<sub>0</sub><i>f</i><sup>η</sup> = 220(±30) <i>f</i><sup>0.66(±0.09)</sup> (0.75≤<i>f</i>≤12Hz). The results from this study are remarkably consistent with frequency dependent quality factor estimates, using local S-wave coda, in south-central Alaska. The consistency between <i>S</i>-coda Q(<i>f</i>) and <i>Lg</i> Q(<i>f</i>) enables constraints to be placed on the mechanism of crustal attenuation in south-central Alaska. For the range of frequencies considered in this study both scattering and intrinsic attenuation mechanisms likely play an equal role.
application/pdf
10.1029/2000GL011732
en
Frequency dependent <i>Lg</i> attenuation in south-central Alaska
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