TY  - JOUR
AU  - Zhang Yang, Ritsema Jeroen
PY  - 2009//
TI  - Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones at the core-mantle boundary
JO  - Geophysical Research Letters
SP  - L19303-
VL  - 36
IS  - 19
KW  - core-mantle boundary
KW  - SKS waves
KW  - amplitudes
KW  - 0545 Modeling
KW  - 7203 Body waves
KW  - 7208 Mantle
KW  -
N2  - Between 105115° degrees, the SKS waveform is complicated by the formation of SPdKS, a wave that has segments of P diffraction along the core mantle boundary. While previous studies have primarily focused on the move-out of SPdKS from SKS, we analyze the concomitant reduction of the SKS amplitude. Long-period SKKS/SKS amplitude ratios present a coherent global pattern. SKKS/SKS is relatively large in North and South American recordings of deep Tonga-Fiji earthquakes but PREM-like in European recordings of earthquakes in South America and North American recordings of earthquakes in Indonesia. Modeling of SKKS/SKS indicate that Ultra-Low Velocity Zones (ULVZs), layers at the base of the mantle with a thickness of about 1020 km and a shear velocity reduction between 2030%, are required to explain high SKKS/SKS ratios and the early move-out of SPdKS.
SN  - 1944-8007
UR  - http://dx.doi.org/10.1029/2009GL040030
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=108), last updated on Mon, 01 Jul 2024 14:40:48 +0200
ID  - ZhangYang2009
ER  -