TY - JOUR
T1 - Strong seismic scatterers near the core-mantle boundary north of the Pacific Anomaly
AU - Ma, Xiaolong
AU - Sun, Xinlei
AU - Wiens, Douglas A.
AU - Wen, Lianxing
AU - Nyblade, Andrew
AU - Anandakrishnan, Sridhar
AU - Aster, Rick
AU - Huerta, Audrey
AU - Wilson, Terry
N1 - Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/4/1
Y1 - 2016/4/1
N2 - Tomographic images have shown that there are clear high-velocity heterogeneities to the north of the Pacific Anomaly near the core-mantle boundary (CMB), but the detailed structure and origin of these heterogeneities are poorly known. In this study, we analyze PKP precursors from earthquakes in the Aleutian Islands and Kamchatka Peninsula recorded by seismic arrays in Antarctica, and find that these heterogeneities extend ~400 km above the CMB and are distributed between 30° and 45°N in latitude. The scatterers show the largest P-wave velocity perturbation of 1.0-1.2% in the center (160-180°E) and ~0.5% to the west and east (140-160°E, 180-200°E). ScS-differential travel-time residuals reveal similar features. We suggest that these seismic scatterers are the remnants of ancient subducted slab material. The lateral variations may be caused either by different slabs, or by variations in slab composition resulting from their segregation process.
AB - Tomographic images have shown that there are clear high-velocity heterogeneities to the north of the Pacific Anomaly near the core-mantle boundary (CMB), but the detailed structure and origin of these heterogeneities are poorly known. In this study, we analyze PKP precursors from earthquakes in the Aleutian Islands and Kamchatka Peninsula recorded by seismic arrays in Antarctica, and find that these heterogeneities extend ~400 km above the CMB and are distributed between 30° and 45°N in latitude. The scatterers show the largest P-wave velocity perturbation of 1.0-1.2% in the center (160-180°E) and ~0.5% to the west and east (140-160°E, 180-200°E). ScS-differential travel-time residuals reveal similar features. We suggest that these seismic scatterers are the remnants of ancient subducted slab material. The lateral variations may be caused either by different slabs, or by variations in slab composition resulting from their segregation process.
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U2 - 10.1016/j.pepi.2016.01.007
DO - 10.1016/j.pepi.2016.01.007
M3 - Article
AN - SCOPUS:84957880046
SN - 0031-9201
VL - 253
SP - 21
EP - 30
JO - Physics of the Earth and Planetary Interiors
JF - Physics of the Earth and Planetary Interiors
ER -