High-Precision Delineation of Fault Geometry and Stress Using Next-Generation Seismic Monitoring: West Texas Case Study

Session: Leveraging Advanced Detection, Association and Source Characterization in Network Seismology [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The hazard posed by seismicity induced potentially by industrial operations such as wastewater disposal and hydraulic fracture completion has been recently a matter of increasing public concern. Location and characterization, often to a relatively rough degree of precision, have been the main focus of monitoring efforts. Regulatory response protocols are typically established for operators should an event exceed a magnitude threshold within a specified distance of their facilities. This is crucial for minimizing potential damage from shaking and public alarm.

Understanding these processes requires that we demand more out of the seismic networks, essentially enhancing the data products to a “next-generation” level, which can potentially provide a detailed characterization of critical geological structures and geomechanics of the study area. In addition to densification of hardware, advanced event processing methods can facilitate reaching this goal. High-precision locations provided by relative relocation methodologies delineate slipping fault structures, often resolving previously unrecognized features. Moment tensor inversion processing also helps reveal the orientations of faults and provides information on the stress regimes in the region. The resolution of these features provides paramount insight into understanding how a field is reacting to changes.

We demonstrate the application of this “next-generation” seismicity monitoring system to the Delaware Basin in West Texas, where we have deployed a network of 25 broadband seismometers complementing TexNet and other existing networks. By aggregating all of these data we obtain a high-resolution earthquake catalog delineating several fault features. Stress inversion from the moment tensor solutions of the highest-quality events shows a dominantly normal stress regime and tangibly resolves a rotation of stress orientation axes transitioning across the basin. We illustrate both the logistical and processing requirements necessary for timely delivery of results highlighting the dynamics of seismicity in an active study area.

Presenting Author: Sepideh Karimi

Authors