Stress controls rupture extent and maximum magnitude of induced earthquakes

Geophysical Research Letters
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Abstract

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 type Article
Publication Subtype Journal Article
Title Stress controls rupture extent and maximum magnitude of induced earthquakes
Series title Geophysical Research Letters
DOI 10.1029/2020GL092148
Volume 48
Issue 11
Year Published 2021
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center
Description e2020GL092148, 10 p.
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