Todd Halihan, Ph.D., P.Gp., is a Professor of Geology at Oklahoma State University and Chief Technical Officer for Aestus LLC. Halihan’s professional interests center in subsurface characterization and sustainable water supply. He has been an associate editor for Ground Water and has served as the Secretary-Treasurer of the U.S. Chapter of the International Association of Hydrogeologists. He served as the Chair of the Hydrogeology Division and the South-Central Section of the Geological Society of America. He currently serves on the Oklahoma governor’s Coordinating Council on Seismic Activity.