Attenuation in the uppermost inner core from PKP data observed at Romanian stations

 

Marian Ivan* and Mihaela Popa **

 

* Dept.of Geophysics, University of Bucharest, 6 Traian Vuia str., 70138 Bucharest o.p.37, Romania.

e-mail: ivam@gg.unibuc.ro

** National Institute for Earth Physics, P.O.Box MG-2, 76900 Bucharest, Romania.

 

 

Abstract: The QP factor at the top of the inner core is using PKPdf and PKPbc phases recorded at Romanian stations from some strong deep Fiji earthquakes. The amplitude spectral ratio method is used. The derived mean value of QP is 295 20 (95% confidence level). The sampled region of the inner core is centered beneath the Japan Sea and the maximum depth of penetration of the PKPdf phase into the inner core is roughly 254 km. A slight increase of QP with depth is observed, although not resolvable, given the data scattering.