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High-Resolution Seismic Monitoring Reveals the State of Stress in the Delaware Basin

Description: 

Wastewater injection from unconventional production is regarded as a prime driver of seismicity in the Delaware Basin of West Texas, which started increasing here lagging the stimulation of the reservoirs. Seismic monitoring in the area has grown with public and private arrays deployed to better characterize the earthquake activity. The combination of such arrays has been used to deliver a highly detailed image of the seismic response in this area: over 700,000 events complete to ML0.2 have been detected and located since April 2019; in that period 7,000+ moment tensors for events above ML2 have been inverted using an amplitude-based, first-motion scheme in tandem with a polarity-based algorithm.

Moment tensors complemented with high-precision locations are used to run a robust spatial stress inversion over the area. Critical to running such inversions is the ability to select the fault plane from the auxiliary plane in the moment tensor. The nearest neighbouring hypocenter locations, after refinement through double-differencing, helps with this problem as often they will illuminate the faults on which these larger events nucleate, allowing for identification of the fault on which the larger event with the moment tensor occurs. By running a series of local stress inversions, and (Monte Carlo) perturbing the solutions to only select stress states that appear stable, we resolve an overall trend of a dominantly normal stress state where there is a slow sweep of azimuths of SHmax from NW-SE trending to EW as one travels from SE to NW across the basin. However there are areas where the stress appears to be much more rapidly varying, and the state appears more strike-slip and the orientation of SHmax likewise changes rapidly over relatively short (<10km) scales.

Session: From Physics to Forecasts: Advancements and Future Directions of Induced Seismicity Research [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Adam

Student Presenter: No

Invited Presentation: 

Poster Number: 106

Authors