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 - Funding Information:
We would like to thank V.F. Cormier and another reviewer for their constructive comments/suggestions, which have greatly improved the quality of the manuscript. We also thank N.J. Mancinelli and P.M. Shearer for providing us the phonon code generously. X. Ma and X. Sun are supported by China National Science Foundation (No. 41274057 ) and the 973 project of Ministry of Science and Technology of China ( 2014CB845901 ), and China National Science Foundation (No. 41330209 ). The Antarctic seismic data were collected with the support of the National Science Foundation of United States under grants ANT-0537597 , ANT-0632209 , and ANT-0838934 . Figures are made using Generic Mapping Tools ( Wessel and Smith, 1995 ). The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms, related metadata, and/or derived products used in this study. IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation under Cooperative Agreement EAR-1261681. This is a contribution to No. IS-2188 of GIGCAS.
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 -