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Session: Advances, Developments and Future Research into Seismicity in Natural and Anthropogenic Fluid-Driven Environments [Poster]

Type: Poster

Date: 4/26/2019

Time: 06:00 PM

Room: Fifth Avenue

[Withdrawn] Moment Tensors of Waste-Water Disposal Induced Seismicity in Southern Kansas

Fluid-injection into the subsurface in the frame of reservoir-engineering activities for hydrocarbon and geothermal energy production has resulted in a dramatic increase of induced seismicity during the last 10 years. This includes four M>5 earthquakes in Oklahoma and Kansas (US) through the reactivation of previously unknown critically stressed and thus hazardous faults in the basement. We investigate seismic recordings of relocated events with local magnitudes ML in the range [1.9, 5.2] from a regional seismic network deployed in southern Kansas since 2014 including 19 broadband stations and 5 accelerometers. Determination of seismic moment tensors and subsequent refinement was done employing the hybridMT package (Kwiatek, 2016). HybridMT inversion is based on the P-waves first ground displacement amplitudes from vertical components and provides unconstrained full, deviatoric, and double-couple constrained moment tensors. The results of moment tensor inversion are refined and suppresses the influence of local path, site, and sensor effects. In this study, we also implemented the use of the horizontal components, thereby increasing the input data by a factor of 3. The refined methodology was tested and tuned on synthetic datasets based on the shear-tensile source model (Vavrycuk, 2001). This model describes the source kinematics by four fault plane parameters (strike, dip, rake) and a tensile angle representing the fault opening. We find that focal mechanisms from the 3-component inversion are generally consistent with the generated synthetic fault plane parameters, signifying the correct performance of the new approach. Furthermore, moment tensor inversion of several tens of events with already reported focal mechanisms (Rubinstein, 2018) appear to be generally consistent between applied methods. In this contribution, first results from statistically significant full moment tensors as well as double-couple solutions from initial ~2,300 seismic events are presented and discussed in the context of their spatial and temporal changes within the investigated area.

Presenting Author: Patricia Martinez-Garzon

Additional Authors