Inner Core Attenuation Measurements

Description

The data files here enable an estimate of the goodness of fit to observed PKIKP body waveforms of a 2-layered model of inner core attenuation, in which the boundary between and upper and lower inner core is varied.

Steps to reproduce

Seismic waveform data were downloaded from IRIS-DMC. An Excel file and text files are provided for P attenuation measurements obtained from fitting the first half-cycle of PKIKP waveforms with an inner core attenuation operator and a far-field source-time function and average mantle attenuation operator for specific earthquake and stations. The best fitting inner core attenuation operator is parameterized by attenuation (1/Qp) at 1 Hz and a low-frequency corner of a relaxation spectrum assumed to be 5 decades wide in frequency (Cormier, V.F., and Li, X., J. Geophs. Res., 2002. Frequency-dependent seismic attenuation in the inner core. The Excel file assumes a 600 km radius of an innermost inner core, with column headings. A series of text files adjusts information in the Excel files for varying the radius of the boundary of the upper and lower inner core between radii 400 to 800 km. A Matlab file reads the text files, plots a Gaussian probability density for the attenuation in the upper and lower inner core, reports the attenuation values at the maximum of the probability density.

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