Constraining maximum event magnitude during injection-triggered seismicity
Ziyan Li, Derek Elsworth, Chaoyi Wang, EGS-Collab, Linda D. Boyd, Z. Frone, E. Metcalfe, A. Nieto, S. Porse, W. Vandermeer, Rob Podgorney, Hai Huang, T. McLing, Ghanashyam Neupane, Aditya Chakravarty, P. J. Cook, Patrick Dobson, C. A. Doughty, Yves Guglielmi, Chet Hopp, Mengsu Hu, R. S. Jayne, S.E. Johnson, K. Kim, Timothy J. Kneafsey, Seiji Nakagawa, Greg Newman, P. V. Petrov, John Carlo Primo, M. Robertson, V. Rodriguez-Tribaldos, J. Rutqvist, M. Schoenball, Eric Sonnenthal, F. A. Soom, Shanna R. Sprinkle, Craig Ulrich, C. A. Valladao, Todd Wood, Y. Q. Zhang, Quanlin Zhou, L. Huang, Yunfei Chen, T. Chen, Benxin Chi, Zhiwei Feng, Luke Frash, Ke Gao, Elchin Jafarov, Satish Karra, N. Makedonska, D. Li, Jun Li, Rajesh Pawar, N. Welch, Pengcheng Fu, R. J. Mellors, C. Morency, Joseph P. Morris, C. S. Sherman, Megan M. Smith, D. C. Templeton, J. L. Wagoner, Joshua A. White, Hui Wu, Johnathan Moore, Sarah Brown, Dustin Crandall, Paige Mackey, Thomas Paronish, S. Workman, B. Johnston, K. Beckers, Jon Weers, Yarom Polsky, Mónica Maceira, Chengping Chai, A. Bonneville, Jeffrey Burghardt, J. Horner, T. C. Johnson, H. Knox, J. Knox, B. Q. Roberts, P. Sprinkle, Chris Strickland, Jonathan Thomle, V. R. Vermeul, Mark D. White, Doug Blankenship, M. Ingraham, T. Myers, Jeffrey J Pope, Paul Schwering, A. Foris, D. K. King, J. Feldman, M. Lee, Jinrong Su, T. Baumgartner
Abstract
Understanding mechanisms controlling fluid injection-triggered seismicity is key in defining strategies to ameliorate it. Recent triggered events (e.g. Pohang, Mw 5.5) have exceeded predictions of average energy release by a factor of >1000x, necessitating robust methodologies to both define critical antecedent conditions and to thereby constrain anticipated event size. We define maximum event magnitudes resulting from triggering as a function of pre-existing critical stresses and fluid injection volume. Fluid injection experiments on prestressed laboratory faults confirm these estimates of triggered moment magnitudes for varied boundary conditions and injection rates. In addition, observed ratios of shear slip to dilation rates on individual faults signal triggering and may serve as a measurable proxy for impending rupture. This new framework provides a robust method of constraining maximum event size for preloaded faults and unifies prior laboratory and field observations that span sixteen decades in injection volume and four decades in length scale.