Seismic anisotropy of the Rio Grande Rift and surrounding regions Tia Barrington and Jay Pulliam, Baylor University The evolution of distinct tectonic provinces in the southwestern United States since the Cretaceous, including the Great Plains, the Colorado Plateau, and the Rio Grande Rift (RGR), has been linked to flat subduction of the Farallon plate (~80 Ma) and then its subsequent foundering (~40 Ma). However, there has been a resurgence in tectonic activity (magmatism, extension, and possibly uplift) much more recently (~10 Ma), so there is no clear connection between the Farallon plate’s foundering and present tectonic activity. Small‐scale, edge‐driven convection is a possible explanation for this renewed activity. Edge‐driven convection, if it is occurring, should extend to the north and south along the margin of the Proterozoic Great Plains craton. Convective flow should have a signature in the upper mantle’s seismic anisotropy and our goal is to determine whether patterns of anisotropy, as determined from SKS splitting that may be consistent with small‐scale convection. SKS splitting measurements were made for 126 broadband stations located on the eastern flank of the Rio Grande Rift. Seventy‐one of these stations were installed in 2008 as an Earthscope Flexible Array deployment called SIEDCAR; the remainderare EarthScope Temporary Array stations. SKS splitting patterns conform both to surface physiographic features as well as to models of the subsurface produced independently. Fast polarization directions near the Rio Grande Rift tend to be sub‐parallel to the RGR but then change to angles that are consistent with North America’s average plate motion, to the east. The surface erosional depression of the Pecos Valley coincides with fast polarization directions that are aligned in a more northerly direction than their neighbors, whereas the topographic high to the east coincides with an easterly change of the fast axis. The area above the mantle “downwelling” anomaly corresponds to unusually small delay times, as well as changes in fast axis directions. Changes in fast axis directions might indicate flow around a fragment of craton that has been eroded from the Great Plains, for example. Small delay times could indicate vertical or attenuated flow. A discontinuity in the Moho as well as subcrustal discontinuities along the Pecos River corresponds to an abrupt change in delay time for the SKS measurements. .