Dynamic fault interaction during a fluid-injection induced earthquake: The 2017 Mw 5.5 Pohang event

Dynamic Fault Interaction during a Fluid-Injection-Induced Earthquake: The 2017 Mw 5.5 Pohang Event

Bulletin of the Seismological Society of America ◽

10.1785/0120200106 ◽

2020 ◽

Vol 110 (5) ◽

pp. 2328-2349

Author(s):

Kadek Hendrawan Palgunadi ◽

Alice-Agnes Gabriel ◽

Thomas Ulrich ◽

José Ángel López-Comino ◽

Paul Martin Mai

Keyword(s):

Fault Plane ◽

Fluid Pressure ◽

Local Stress ◽

Stress Conditions ◽

Fluid Injection ◽

Geothermal System ◽

Dynamic Rupture ◽

Fault Interaction ◽

Induced Earthquake ◽

Secondary Fault

ABSTRACT The 15 November 2017 Mw 5.5 Pohang, South Korea, earthquake has been linked to hydraulic stimulation and fluid injections, making it the largest induced seismic event associated with an enhanced geothermal system. To understand its source dynamics and fault interactions, we conduct the first 3D high-resolution spontaneous dynamic rupture simulations of an induced earthquake. We account for topography, off-fault plastic deformation under depth-dependent bulk cohesion, rapid velocity weakening friction, and 1D subsurface structure. A guided fault reconstruction approach that clusters spatiotemporal aftershock locations (including their uncertainties) is used to identify a main and a secondary fault plane that intersect under a shallow angle of 15°. Based on simple Mohr–Coulomb failure analysis and 180 dynamic rupture experiments in which we vary local stress loading conditions, fluid pressure, and relative fault strength, we identify a preferred two-fault-plane scenario that well reproduces observations. We find that the regional far-field tectonic stress regime promotes pure strike-slip faulting, whereas local stress conditions constrained by borehole logging generate the observed thrust-faulting component. Our preferred model is characterized by overpressurized pore fluids, nonoptimally oriented but dynamically weak faults and a close-to-critical local stress state. In our model, earthquake rupture “jumps” to the secondary fault by dynamic triggering, generating a measurable non-double-couple component. Our simulations suggest that complex dynamic fault interaction may occur during fluid-injection-induced earthquakes and that local stress perturbations dominate over regional stress conditions. Therefore, our findings have important implications for seismic hazard in active georeservoir.

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Controlling Induced Earthquake Magnitude by Cycled Fluid Injection

Geophysical Research Letters ◽

10.1029/2021gl092885 ◽

2021 ◽

Vol 48 (19) ◽

Author(s):

J. B. Zhu ◽

J. Q. Kang ◽

D. Elsworth ◽

H. P. Xie ◽

Y. Ju ◽

...

Keyword(s):

Earthquake Magnitude ◽

Fluid Injection ◽

Induced Earthquake

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Fluid Injection and Seismic Activity in the Northern Montney Play, British Columbia, Canada, with Special Reference to the 17 August 2015Mw 4.6 Induced Earthquake

Bulletin of the Seismological Society of America ◽

10.1785/0120160175 ◽

2017 ◽

Vol 107 (2) ◽

pp. 542-552 ◽

Cited By ~ 35

Author(s):

Alireza Babaie Mahani ◽

Ryan Schultz ◽

Honn Kao ◽

Dan Walker ◽

Jeff Johnson ◽

...

Keyword(s):

British Columbia ◽

Special Reference ◽

Seismic Activity ◽

Fluid Injection ◽

Induced Earthquake

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Forecasting Induced Earthquake Hazard Using a Hydromechanical Earthquake Nucleation Model

Seismological Research Letters ◽

10.1785/0220200215 ◽

2021 ◽

Author(s):

Justin L. Rubinstein ◽

Andrew J. Barbour ◽

Jack H. Norbeck

Keyword(s):

United States ◽

Earthquake Hazard ◽

Fluid Injection ◽

Hazard Models ◽

Induced Earthquakes ◽

Induced Earthquake ◽

Earthquake Nucleation ◽

Nucleation Model ◽

Central United States ◽

The U.S

Abstract In response to the dramatic increase in earthquake rates in the central United States, the U.S Geological Survey began releasing 1 yr earthquake hazard models for induced earthquakes in 2016. Although these models have been shown to accurately forecast earthquake hazard, they rely purely on earthquake statistics because there was no precedent for forecasting induced earthquakes based upon wastewater injection data. Since the publication of these hazard models, multiple physics-based methods have been proposed to forecast earthquake rates using injection data. Here, we use one of these methods to generate earthquake hazard forecasts. Our earthquake hazard forecasts are more accurate than statistics-based hazard forecasts. These results imply that fluid injection data, where and when available, and the physical implications of fluid injection should be included in future induced earthquake hazard forecasts.

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A new approach to the hydraulic fracture geometric dimensions determination

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2017.1.018 ◽

2017 ◽

Vol 12 (1) ◽

pp. 126-134

Author(s):

A.M. Ilyasov

Keyword(s):

Exact Solution ◽

Hydraulic Fracture ◽

Pressure Gauge ◽

Hyperbolic Type ◽

Fluid Injection ◽

Fracturing Fluid ◽

New Approach ◽

Gauge Data ◽

Bottomhole Pressure ◽

Half Length

Based on the generalized Perkins-Kern-Nordgren model (PKN) for the development of a hyperbolic type vertical hydraulic fracture, an exact solution is obtained for the hydraulic fracture self-oscillations after terminating the fracturing fluid injection. These oscillations are excited by a rarefaction wave that occurs after the injection is stopped. The obtained solution was used to estimate the height, width and half-length of the hydraulic fracture at the time of stopping the hydraulic fracturing fluid injection based on the bottomhole pressure gauge data.

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