Evidence of ancient rifts beneath Texas
Continental rifts are defined as geological features where Earth's lithosphere is pulled away by surface expansion of the Earth. Their physiographic features include linear rift valleys associated with active volcanism. Many rifts fail to split a continent and ancient rifts that failed to split can be found by using seismic waves to image these ancient structures. Using seismic data collected by EarthScope USArray stations in Texas, teleseismic receiver functions was calculated and utilized surface wave dispersion curves to simultaneously invert for the 2D velocity structure beneath each seismic station. EarthScope is a scientific program funded by NSF that provides geophysical data from all around the United States to students and researcher for free. The data for this research came from USArray, the network of 400 transportable seismic stations now stationed in the central US states, including Texas. With the calculated receiver functions, a map was produced to show preliminary 3-D crust/upper mantle boundary structure and the velocity ratio of P and S waves. Based on this in formation, receiver function results allow us locate and analyze ancient rift zones that exist in Texas that are characterized by a shallow crust mantle boundary and high velocity ratio. Finally, with this information on ancient rifts, comparison will be made between the result from this research and the Rio Grande Rift in New Mexico. The goal for this comparison is to determine whether Rio Grande rift is still active or doomed to be another failed rift.
Irie, Keisuke, "Evidence of ancient rifts beneath Texas" (2011). ETD Collection for University of Texas, El Paso. AAI1503729.