Characterizing seismogenic structures and stress state for the western Midland Basin, Texas, the United States

Abstract

Earthquake activities in areas across the Central Basin Platform and the Midland Basin have significantly increased since 2019. There are also ongoing oil and gas industrial activities present in this region which may have contributed to the recently increased seismicity. Meanwhile, the induced seismicity has allowed us to disclose concealed seismogenic structures that otherwise had not been previously discovered. This paper presents results of a most recent study of characterizing seismogenic structures in this region. We used the hypoDD algorithm to relocated seismicity and better reveal the geometry of the seismogenic structures. In addition, we performed waveform moment tensor inversion to determine earthquakes’ source mechanism for our study area. Furthermore, the state of stress is determined by using stress inversion on the basis of the obtained source mechanism. As a result, five distinct earthquake clusters have been identified. All of them commonly present a linear geometry trending in either nearly W-E orNW-SE directions. The collective pattern of source mechanisms indicates a strong involvement of the strike-slip faulting component, implying a lateral-extensional tectonic regime. Across the five earthquake clusters, however, the orientation of stress field has a significant change near the Central Basin Platform. A further study on this orientation change is needed.