Resistivity Structure of the Alabama-Oklahoma Lineament and Mississippi Embayment: Insights Into Crustal Weakness, Heat Flow, and Seismicity of the Region
Abstract
The Alabama–Oklahoma Lineament (AOL) is a major crustal boundary that intersects the Mississippi Embayment (ME) and may influence intraplate deformation in the southern United States. We present the first regional magnetotelluric (MT) resistivity models across the AOL–ME system using EarthScope data and two-dimensional inversion. All southwest–northeast profiles image a persistent northeast-dipping conductive structure (50–100 Ω m) extending from the lower crust into the upper mantle (≥120 km depth), bounded by more resistive lithosphere (500–1,000 Ω m). This conductor aligns with the mapped trend of the AOL and Ouachita thrust belt, suggesting a lithosphere-penetrating weak zone consistent with fossil subduction, long-lived transform motion, and/or metasomatic alteration. West–East profiles reveal a separate, very low resistivity anomaly (<10 Ω m) beneath and west of the Mississippi Embayment in Arkansas, spatially coincident with swarm style seismicity and previously identified low-velocity mantle structure. In contrast, the northern embayment beneath the New Madrid Seismic Zone remains comparatively resistive and cool, consistent with a brittle intraplate environment capable of hosting large earthquakes. These results provide the first electrical constraints on lithospheric segmentation across the AOL–ME region and highlight contrasting mechanisms of weakness for example, metasomatized mantle corridors versus cooler brittle crust, that may govern seismic behavior in the central United States.
Publication Title
Earth and Space Science
Recommended Citation
Sarker, K., & Cramer, C. (2026). Resistivity Structure of the Alabama-Oklahoma Lineament and Mississippi Embayment: Insights Into Crustal Weakness, Heat Flow, and Seismicity of the Region. Earth and Space Science, 13 (5) https://doi.org/10.1029/2025EA004581
