Factors Controlling the Rate and Magnitudes of Injection-Induced Earthquakes

Jean-Philippe Avouac, & Taeho Kim

Published September 10, 2023, SCEC Contribution #13189, 2023 SCEC Annual Meeting Poster #155

Advancements in operations central to the world’s transition to a greener economy such as geothermal energy are hampered by a lack of understanding and control of the maximum magnitude event that orders immediate suspension of all operations. Understanding what governs the magnitudes of injection-induced seismicity could help develop sophisticated designs of industrial operations that optimize their potential to offset CO2 emissions and to advance our understanding of far more devasting earthquakes that pose even greater immediate risk to civil safety. Here, we focus on the magnitude-frequency distribution of seismicity induced by the 2018 geothermal stimulation in Otaniemi, Finland and demonstrate similar correlations observed for tectonic earthquakes in addition to dependencies on the injections. Namely, we observe a dominant, negative correlation of the b-value and Mmax to depth, and additional negative correlations to cumulative injected volume and pore pressure. Negative correlations of the b-value with depth suffer from uncertainty associated with attenuation. Additionally, cumulative injected volume shows a positive correlation to depth in Otaniemi. Our analysis of the relationship to pore pressure should be free of such uncertainties, and we hypothesize that it derives from homogenization of the initially heterogeneous stress field due to slip induced by pore pressure increase.

Key Words
Induced Seismicity Magnitudes

Citation
Avouac, J., & Kim, T. (2023, 09). Factors Controlling the Rate and Magnitudes of Injection-Induced Earthquakes. Poster Presentation at 2023 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Forecasting and Predictability (EFP)