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The upper-mantle discontinuities underneath the GRF array from P-to-S converted phases


Title (Dublin Core)

en-US The upper-mantle discontinuities underneath the GRF array from P-to-S converted phases

Description (Dublin Core)

en-US A data-processing method is applied which includes a rotation of the three components, normalization and delay-and-sum of broadband records of earthquakes from a large distance and azimuth distribution, recorded at a single station (or an array). Clear P-to-S converted phases at the mantle discontinuities are observed in the Grafenberg records, after this data processing. Theoretical seismograms are computed for the PREM model and processed in the same way as the observed data. A comparison with the data shows that the depth interval between the two discontinuities in the mantle transition zone (those at 400 and 670 km depth in PREM) is around 240 km. The 670-km discontinuity is sharper than the 400-km discontinuity and is comparable in sharpness with the crust-mantle transition, as far as it is possible to judge from the broadband data used. There are indications of pronounced lateral heterogeneity of the 400-km transition, underneath GRF. We have also observed converted and multiply reflected shear waves in the crust, which set sensitive limits to the average crustal model underneath the array. These data suggest that the velocity jump at the Moho is smaller than indicated by refraction studies.

Creator (Dublin Core)

Kind, R.
Vinnik, L.P.

Subject (Dublin Core)

en-US Upper-mantle transition zones
en-US P-to-S conversions
en-US Theoretical seismograms
en-US Seismology

Publisher (Dublin Core)

en-US Journal of Geophysics

Date (Dublin Core)


Type (Dublin Core)

en-US Peer-reviewed Article

Format (Dublin Core)


Identifier (Dublin Core)

Source (Dublin Core)

en-US Journal of Geophysics; Vol 62 No 1 (1988): Journal of Geophysics; 138-147

Language (Dublin Core)


Relation (Dublin Core)