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Factors That Can Influence the Fault Activation Process: Examples From Wastewater-induced Sequences in Oklahoma and Geothermal Fields in Utah

Description: 

Earthquake rupture physics and sequence evolution exhibit varied spatiotemporal patterns. The increased seismicity associated with energy exploration in recent years provides us with an opportunity to further probe the factors that influence the these patterns. In this study, we hope to synthetize new and published observations of earthquake and stress evolution from wastewater injection induced sequences in Oklahoma and induced seismicity at Enhanced Geothermal sites to better understand the interactions among stress, fault geometry and earthquakes. Qin et al. 2022 used focal mechanisms to reveal differences in the temporal evolutions of earthquake clusters with respect to fault architecture and orientation to the stress field. Optimally oriented, near-vertical, narrow faults lead to more burst-like behaviors with larger events, while more complex, mesh-like fault geometries lead to more swarm-like behavior with more extended sequence duration. Directivity analysis on two contrasting sequences confirms simpler fault structures for the more optimally oriented fault. Directivity also finds that the nodal plane more well aligned with stress field tends to be the fault plane rupture during the earthquake for both cases. Extending the focal mechanism and stress field analysis work to Enhanced Geothermal Site in Utah found distinct structures with different spatiotemporal evolution and activation timeline from stimulation, that are influenced by stress field and structure orientation. Further quantitative comparison among different sequences will be updated.

Session: Mechanistic Insights into Fluid-induced Earthquakes from the Laboratory to the Field [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Xiaowei

Student Presenter: No

Invited Presentation: 

Poster Number: 92

Authors