TY  - JOUR
AU  - Merrer, S.
AU  - Cara, M.
AU  - Rivera, L.
AU  - Ritsema, J.
PY  - 2007//
TI  - Upper mantle structure beneath continents: New constraints from multi-mode Rayleigh wave data in western North America and southern Africa
JO  - Geophysical research letters
VL  - 34
PB  - American Geophysical Union
KW  - Rayleigh waves
KW  - upper mantle
KW  - 7208 Seismology: Mantle
KW  - 7255 Seismology: Surface waves and free oscillations
KW  - 7290 Seismology: Computational seismology
N2  - We estimate the averaged 1-D shear-wave velocity of the upper mantle beneath western North America and the Kaapvaal region in southern Africa by inverting dispersion measurements of fundamental and higher Rayleigh modes recorded by ?2000 km aperture broadband arrays. The overtones at periods exceeding 25 s constrain the averaged 1-D shear-wave velocity to 650 km depth across the regional arrays. Our overtone analysis confirms the shear-wave velocity differences observed in global tomographic models with similar horizontal resolution: the western North American mantle features a prominent low velocity zone at depths 50–200 km, while the shear velocity in the upper 180–200 km of the mantle beneath southern Africa is at least 6% higher than in western North America which we interpret as the expression of a cratonic keel. There is no resolvable difference in shear-wave velocity between southern Africa and western North America below a depth of about 300 km.
SN  - 0094-8276
UR  - http://dx.doi.org/10.1029/2006GL028939
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=5540), last updated on Mon, 20 Apr 2009 14:32:38 +0200
ID  - Merrer_etal2007
ER  -