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Detection of a ULVZ at the base of the mantle beneath the northwest Pacific
Author(s) -
Xu Yan,
Koper Keith D.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl039387
Subject(s) - geology , subduction , mantle (geology) , seismology , slab , slowness , pacific plate , seismic tomography , pacific ocean , geophysics , tectonics , oceanography
We used the Yellowknife seismic array (YKA) to measure the slowness of 1,371 P and P diff waves from earthquakes occurring in the circum‐Pacific region. The corresponding anomalies in P ‐velocity show a sharp reduction of up to 6% across a patch of the lowermost mantle beneath the Northwest Pacific with lateral dimensions of several hundred kilometers. The location of this ultra low velocity zone (ULVZ) correlates with a long‐wavelength compositional boundary revealed by probabilistic mantle tomography. We interpret the ULVZ as partial melt created by paleo‐slab material that is being swept laterally from northwestern Pacific subduction zones towards the large, chemically distinct province beneath the south‐central Pacific.