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PKIIKP and the average velocity of the inner core
Author(s) -
Massé R. P.,
Flinn Edward A.,
Seggelke R. M.,
Engdahl E. R.
Publication year - 1974
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl001i001p00039
Subject(s) - inner core , geology , radius , geodesy , core (optical fiber) , outer core , travel time , reflection (computer programming) , phase (matter) , table (database) , seismology , boundary (topology) , geometry , physics , optics , mathematics , mathematical analysis , computer security , engineering , quantum mechanics , computer science , transport engineering , data mining , programming language
The phase PKIIKP, which is once reflected from the underside of the inner core boundary, was detected at LASA for a large Novaya Zemlya event at an epicentral distance of 63°. The detection was verified by a technique similar to the VESPA process. Clear arrivals for the phases PcP, P2KP, P4KP, and P7KP were also observed. The near‐side reflection PKiKP was unfortunately not observed for this event, but it is nevertheless possible to estimate the compressional velocity in the upper half of the inner core by using the differential PKIIKP‐PcP travel time. Using this single observation, we estimate the average velocity in the outer half of the inner core to be 11.0 km/sec. This number changes by less than 0.1 km/sec for variations in inner core radius from 1215 to 1230 km, for possible errors in the observed differential times of several seconds, and for reasonable differences in the outer core velocity model ( Gilbert et al ., 1973, vs. Jordan , 1972). A travel time table for PKIIKP is given.