Investigating Complex Triggering in the Midland Basin, Texas, Using Converted Phases
Description:
Intraplate seismicity in previously aseismic areas within the Permian Basin, Texas, has steadily increased since 2009 (Frohlich et al., 2020) and now outpaces California. The Midland Basin, the eastern lobe of the Permian, has experienced multiple moderate magnitude earthquakes (M4-6), including the recent 2023 M5.4. While it is generally accepted that oil and gas development is linked to the seismic activity, and saltwater disposal (SWD) is a significant triggering mechanism in the Midland basin, understanding if it is the shallow (<1.5 km subsurface) or only the deep (2.3-3.4 km subsurface) injection practices that require mitigation remains an open question. The problem is complicated by uncertainties in earthquake depth of +/-3 km that reflect changes in network geometry in space and time and complicated basin geology. Here, we use body wave conversions common for shallow earthquakes in the sedimentary basins that can be extracted as a third arrival for constraining epicentral depths. We present a series of synthetic seismograms used to investigate depth to conversion interfaces and gain an intuitive understanding of the subsurface. This study utilizes REFSEIS, a reflectivity based program designed to generate synthetic near and far field seismograms over prescribed event-station distances; flexible 1D Vp, Vs, density, Qp and Qs; and moment tensors. We explore Midland Basin specific velocity models and moment tensor solutions to generate a suite of synthetic seismograms to forward model how the waveform is influenced when the source depth and source to receiver distance changes. The synthetic dataset then guides analyst identification of converted phases for use in relocation studies.
Session: Understanding and Managing Induced Seismicity [Poster]
Type: Poster
Date: 4/19/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Julia M. Rosenblit
Student Presenter: Yes
Invited Presentation:
Authors
Julia Rosenblit Presenting Author Corresponding Author jrosenblit@smu.edu Southern Methodist University |
Heather De Shon hdeshon@mail.smu.edu Southern Methodist University |
Alexandros Savvaidis alexandros.savvaidis@beg.utexas.edu Texas Seismological Network |
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Investigating Complex Triggering in the Midland Basin, Texas, Using Converted Phases
Category
Understanding and Managing Induced Seismicity