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Shear‐wave splitting variations across an array in the southern North Island, New Zealand
Author(s) -
MarsonPidgeon Katrina,
Savage Martha K.
Publication year - 2004
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 - 10.1029/2004gl021190
Subject(s) - geology , seismology , subduction , shear wave splitting , shear (geology) , anisotropy , range (aeronautics) , spatial variability , geodesy , tectonics , paleontology , statistics , physics , materials science , mathematics , quantum mechanics , composite material
We observe significant spatial variations in shear wave splitting from deep teleseismic S and regional ScS recorded on an array in the fore‐arc region of the Hikurangi subduction zone, New Zealand. We also observe variations from different events recorded at the same station. The fast polarization directions range between 23° and 72° and the delay times range between 0.75 s and 1.80 s. These observations contrast with previous SKS studies in New Zealand where little spatial variation is seen, and highlights the importance of using a variety of phases with different periods. Our observations are consistent with a model in which a lateral anisotropic boundary runs ∼NE‐SW in a zone between Kapiti Island and ∼40 km east of the Tararua mountain range. The anisotropic boundary is possibly related to a prominent vertical velocity feature near Kapiti Island.