TY  - JOUR
A1  - Kastle, Emanuel D.
A1  - Weber, Michael
A1  - Krüger, Frank
T1  - Complex Deep Structure of the African Low-Velocity Zone
T2  - Bulletin of the Seismological Society of America
N2  - We use recently deployed seismological arrays in Africa to sample a 2D cross section through the mantle down to the core-mantle boundary (CMB). By making use of travel-time residuals of S, ScS, and SKS phases, a new shear-velocity model of the African low-velocity zone (ALVZ) is derived. Our model suggests between 1.2% shear-velocity reduction at the top and 5% at the bottom with respect to 1D reference models. The average reduction over the whole low-velocity zone (LVZ) amounts to 2% in the presented model and is therefore about twice as strong as values found in global tomographic models. The top of the LVZ reaches up to 1200-km depth, and its lateral extent at the CMB is about 35 degrees. We propose the existence of a gap of 300 km, splitting the structure into two blocks. Our results are based on remarkable differences in SK(K) S travel-time residuals over a few degrees distance. The complexity of the structure could provide a key to an improved understanding of the deep-mantle LVZ dynamics and composition by comparison to geodynamic models. The gap in the model might suggest that the 2D cross section is cutting through a 3D indentation in the boundary of the ALVZ but may also be interpreted as a sign of two individual plumes, rather than one large homogeneous upwelling.
Y1  - 2017
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/46461
SN  - 0037-1106
SN  - 1943-3573
VL  - 107
SP  - 1688
EP  - 1703
PB  - Seismological Society of America
CY  - Albany
ER  -