Abstract View

Volume 29 Issue 7 (July 2019)

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Article, pp. 4-10 | Full Text | PDF (5.4MB)

Synoptic View of Lithospheric S-Wave Velocity Structure in the Southern United States: A Comparison of 3D Seismic Tomographic Models

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Alden Netto, Jay Pulliam

Dept. of Geosciences, Baylor University, Waco, Texas 76706, USA

Patricia Persaud

Dept. of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA


The southern U.S. continental margin records a history spanning ca. 1.2 Ga, including two Wilson cycles. However, due to a thick sediment cover, the paucity of significant local seismicity, and, until recently, sparse instrumentation, details of this passive margin’s tectonomagmatic evolution remain disputed. This paper compares recent S-wave tomography and crustal thickness models based on USArray data to help establish a framework for geodynamic interpretation. Large-scale patterns of crustal velocity anomalies, corresponding to major regional features such as the Ouachita orogenic front and the Precambrian margin, are generally consistent between the models. The spatial extent of smaller-scale tectonic features, such as the Sabine Uplift and Wiggins block, remains poorly resolved. An inverse relationship between crustal thickness and Bouguer gravity across the continental margin is observed. This model comparison highlights the need for additional P-wave tomography studies and targeted, higher density station deployments to better constrain tectonic features.

Manuscript received 19 Sept. 2018. Revised manuscript received 10 Jan. 2019. Manuscript accepted 14 Jan. 2019. Posted 13 Feb. 2019.

© The Geological Society of America, 2019. CC-BY-NC.