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Insights Into Fault Behavior in Southern Kansas From Stress Evolution Modeling of Multiple Induced Earthquake Sequences

Description: 

Southern Kansas has experienced an increase in seismicity largely associated with wastewater disposal in the last decade, with earthquake rates being the highest in 2013-2017, including a Mw 4.8 earthquake near Milan, Kansas on 12 November 2014. Detailed studies of seismicity in the area identified a collection of planar fault structures on which earthquakes concentrated, representing both normal and strike-slip faults (Shoenball and Ellsworth, 2017). We used a machine-learning enhanced seismic catalog developed by Park et al. (2022) to perform simple stress modeling for multiple sequences of induced earthquakes in southern Kansas. Our objective is to explore the mechanisms responsible for driving those sequences. These sequences contain many earthquakes that are consistent with earthquake-to-earthquake triggering, suggesting static stress changes have an important role in their evolution. However, each sequence also includes significant numbers of earthquakes that re-rupture areas where previous earthquakes happened and where the driving stresses should be reduced. Assuming a characteristic stress drop for all earthquakes of 3 MPa, between one quarter and one third of earthquakes in each sequence occurred in areas of the fault that had stress changes from previous earthquakes <-1 MPa. This suggests that aseismic slip or continued fault weakening from ongoing pore pressure increase. Our results indicate that multiple processes likely play a role in driving the evolution of earthquakes during induced earthquake sequences in southern Kansas.

Session: Mechanistic Insights into Fluid-induced Earthquakes from the Laboratory to the Field - I

Type: Oral

Date: 4/15/2025

Presentation Time: 02:15 PM (local time)

Presenting Author: Rosamiel

Student Presenter: Yes

Invited Presentation: No

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Authors