Learning Earthquake Physics from Induced Seismicity in Oklahoma

Understanding the interplay between seismic rupture, slow deformation and fluids is a long-standing challenge, and earthquakes induced by human activity offer a controlled setting for studying it. Oklahoma historically had little seismicity, but from 2009 activity surged after years of wastewater injection into deep rock formations, culminating in the 2016 M5.8 Pawnee earthquake. Tighter regulation has since driven a substantial decrease in seismicity, yet in 2024 an M5.1 Prague earthquake re-ruptured the fault system that hosted its 2011 M5.7 predecessor. The talk discusses outstanding questions from plate-boundary fault systems and argues that intraplate and induced seismicity provide unique observations and insights. First, combined geodetic (GNSS and InSAR) and seismic analysis and modelling at Pawnee reveal how microseismicity, fault slip and transient deformation evolved through the 2016 sequences amid two decades of fluid injection. Second, seismic source analysis of the 2011 and 2024 Prague sequences suggests persistent structural and dynamic controls on earthquake stress changes, with implications for induced seismic hazard. Together these examples illuminate the coupled effects of fault networks, fluids, deformation and rupture across spatial and temporal scales. The seminar is part of the Dr. James Carter Lecture Series of the Department of Sustainable Earth Systems Sciences.