Controlling Induced Earthquake Magnitude by Cycled Fluid Injection. Issue 19 (4th October 2021)

• Record Type: Journal Article
• Authors: Zhu, J. B.; Kang, J. Q.; Elsworth, D.; Xie, H. P.; Ju, Y.; Zhao, J.
• Is Part Of: Geophysical research letters. Volume 48:Issue 19(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-04
• Subjects: induced earthquake -- fluid injection -- laboratory earthquake -- earthquake mitigation; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL092885
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The possibility of controlling induced earthquake magnitude through managed metering of water injection has yet to be rationalized. Mechanisms of reducing magnitudes of induced events through cycled fluid injection remain unclear. To explore such mechanisms and this possibility, we report experiments with water injection into laboratory faults. Water injection results in early triggering for both single and cycled injection. However, the maximum moment magnitude and total energy of the repeating induced earthquakes during cycled water injection are both lower than those of induced earthquakes induced with continuous injection and for natural earthquakes without water injection. Higher permeability of the host reduces the number of injection‐induced earthquakes but increases their moment. With an increasing number of water injection cycles, both maximum moment and total energy decrease, particularly as permeability decreases, while the number of induced events increases. The moment magnitude of induced events can thereby be controlled through cycled fluid injection. Plain Language Summary: Fluid injection‐triggered earthquakes have been documented worldwide. Although it is clear that fluid pressure triggers fault slip and results in induced earthquakes, the possibility of controlling induced earthquakes through managed metering of water injection has not been rigorously examined. We performed experiments with single and cycled injection into laboratory faults. Our results show that cycled water injection into a fault could successfully reduce both the maximum magnitude of the individual induced seismic events and the total radiated energy—by setting appropriate water injection schedules. The magnitude and number of induced events are dependent on the number of water injection cycles and rock permeability. These results may provide a better understanding of managing and preventing large induced earthquakes. Key Points: Water injection results in early occurrence of the fault seismic slip for both single and cycled injection Cycled water injection could reduce both the maximum magnitude of the individual induced seismic events and the total released energy Both maximum moment and total energy decrease with an increasing number of water injection cycles