Meeting ID: 926 1353 1749
Passcode: 604705
Presenter
Dino Huang, Ph.D.
Research Associate
Bureau of Economic Geology
Jackson School of Geosciences
The University of Texas at Austin
Description
Earthquake activities in the greater Permian Basin have significantly increased since 2008. Over time, seismic events were unevenly distributed throughout the basin and often occurred in a number of seismic zones which may have disclosed concealed seismogenic structures. Among them, the Snyder area of northwest Texas has a significant seismicity rate, second only to that of the Delaware Basin, a subunit of the greater Permian Basin. A recent study has investigated the concealed seismogenic structures in the Snyder area using three main approaches: (1) relocated and delineated seismicity, (2) performed waveform moment tensor inversion to determine earthquakes’ source mechanisms, as well as (3) conducted stress inversion to assess the stress state. In this presentation I will present the study results. Results show that seismicity are concentrated in the basement-top. The collective pattern of source mechanisms presents a fault system comprising a mix of strike-slip and normal faults. The overall geometry of seismicity distribution illustrates an apparent northeast-to- southwest lineation, aligning with the direction of maximum horizontal stress. This study has further identified several seismogenic cycles in 2017-2021. Results also demonstrate a temporal variation of b-value, which should be associated with the perturbation of effective normal-stress along the preexisting fault planes during the earthquake cycles. It also presents a series of foreshock-mainshock-aftershock sequences that seemingly resemble tectonic-like seismicity. All of which suggest that seismicity in the Snyder area involves re-activation of basement-rooted faults.
