Shear‐wave splitting measurements in the Galápagos archipelago show a rapid change
from consistently oriented anisotropy to no measurable anisotropy. At the western edge of
the archipelago delay times are 0.4–0.9 s and fast polarization directions are 81–109° E.
These directions are consistent with anisotropy resulting from shear of the asthenosphere by
the overlying plate; there is no indication of fossil lithospheric anisotropy in the plate
spreading direction. In contrast, beneath the center of the archipelago the upper mantle is …

We report measurements of teleseismic shear wave splitting in the Galápagos Archipelago.
The inferred lateral variations in azimuthal anisotropy allow us to examine the dynamics of
an evolving hotspot-ridge system. The data are from SKS and SKKS phases, as well as S
waves from deep sources, recorded by a relatively dense network of 10 portable broadband
seismometers deployed from 1999 to 2003 for the IGUANA (Imaging Galápagos Upwelling
and Neotectonics of the Archipelago) experiment and from the GSN broadband station in …