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Elliptical‐anisotropic eikonal phase velocity tomography
Author(s) -
de Ridder S. A. L.,
Biondi B. L.,
Nichols D.
Publication year - 2015
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 - 10.1002/2014gl062805
Subject(s) - geology , eikonal equation , anisotropy , tomography , seismology , overburden , phase velocity , ellipse , seismic wave , phase (matter) , seismic anisotropy , geophysics , seafloor spreading , geometry , physics , optics , geotechnical engineering , mathematics , quantum mechanics , mantle (geology)
We formulated an anisotropic eikonal tomography approach for phase velocities based on a two‐dimensional elliptical‐anisotropic wave equation. We can fit the parameters of the ellipse directly from measured first‐order traveltime surface gradients and constrain these parameters to vary smoothly over space. The method is applied to Scholte waves in virtual seismic sources from stations in the Life of Field Seismic Ocean Bottom Cable array installed over the Ekofisk field. The fast directions of the azimuthally anisotropic Scholte wave velocities form a large circular pattern over the Ekofisk field. This pattern dominates the Scholte wave phase velocities at Ekofisk between 0.7 and 1.1 Hz. It results from the overburden stress state and from seafloor subsidence induced by decades of hydrocarbon extraction.