Abstract
A number of deep earthquakes from the Fiji-Tonga region were used to study the properties of the core-mantle boundary (CMB). The investigation was restricted to an area with a diameter of only a few hundred kilometers at the CMB, the use of a cluster of neighboring events yielding redundant sampling and rather good resolution. The components of the investigation are: (i) a classical stacking procedure to search for additional reflectors near the CMB; (ii) a deconvolution of seismograms and a stack of the inferred reflector series for the same purpose; (iii) a matched filter method to determine PcP travel times and PcP/P amplitude ratios precisely; and (iv) a comparison with synthetic seismograms to check the consistency of derived travel-time residuals and PcP amplitude variations in the presence of CMB topography. While we do not see any additional reflector for epicentral distances around 35°, we detect by stacking seismograms recorded at 70° an additional phase which might be caused by a reflection from the top of D″. We show that PcP travel-time residuals must not be interpreted as being caused exclusively by CMB topography. An additional investigation of synthetics provides some constraints on dominant wavelengths and corresponding amplitudes of CMB undulations. For wavelengths of 50–400 km the elevation cannot exceed 2–3 km, if PcP is observed in this particular area.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
