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Stress controls rupture extent and maximum magnitude of induced earthquakes

May 20, 2021

Seismic hazard forecasts of induced seismicity often require estimates of the maximum possible magnitude (Mmax). Empirical models suggest that maximum magnitudes, or expected number of earthquakes, are related to the volume of injected fluid. We perform a suite of 3D physics-based earthquake simulations with rate- and state-dependent friction, systematically varying the area of the pressurized region and the amplitude of the initial homogeneous or heterogeneous shear stress. Using the resulting catalog we explore the conditions that result in pressure-controlled versus runaway ruptures that extend outside the pressurized zone. We find that proposed empirical scaling laws correctly predict Mmax when shear stresses are further from failure (≤90% of maximum shear stress) and for high amplitude stress fields. Runaway ruptures are observed for higher initial shear stresses and smoother stress fields. In these cases, runaway ruptures occur early after the onset of injection and rarely preceded by foreshock activity.

Publication Year 2021
Title Stress controls rupture extent and maximum magnitude of induced earthquakes
DOI 10.1029/2020GL092148
Authors K. A. Kroll, Elizabeth S. Cochran
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70230774
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center