Open AccessBroadband observations of PS conversions from the upper mantle in Eurasia
Author(s) -
Stammler K.,
Kind R.,
Kosarev G. L.,
Plešinger A.,
Horálek J.,
Qiyuan Liu,
Vinnik L. P.
Publication year - 1991
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1991.tb00814.x
Subject(s) - classification of discontinuities , coda , broadband , geology , discontinuity (linguistics) , seismology , noise (video) , mantle (geology) , scattering , geodesy , geophysics , physics , optics , mathematics , mathematical analysis , computer science , artificial intelligence , image (mathematics)
SUMMARY The delay‐and‐sum method by Vinnik (1977) to detect weak PS conversions in the P coda is applied to German, Czechoslovakian and Chinese broadband data. Clear phases (a factor 4‐5 above the noise level) are observed in the 3‐11 s period band from the 670 and 400 km discontinuities after summing several hundred traces. The decisive step to obtain such a good signal‐to‐noise ratio was the summation of records from stations in different regions. The summation of a large number (many hundreds) of traces of a single station does not result in similar improvements because of coherent signal‐generated noise due to scattering below the station. There are weak indications of a 520 km discontinuity in our data. The delay times relative to P of the converted phases are stable within 1 s between central Europe and China.