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Quaternary Reelfoot fault deformation in the Obion River valley, Tennessee, USA

Delano, Jaime E.; Briggs, Richard W.; Jobe, Jessica Thompson; Gold, Ryan D.; Engelhart, Simon E.

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Authors

Jaime E. Delano

Richard W. Briggs

Jessica Thompson Jobe

Ryan D. Gold



Abstract

Blind reverse faults are challenging to detect, and earthquake records can be elusive because deep fault slip does not break the surface along readily recognized scarps. The blind Reelfoot fault in the New Madrid seismic zone in the central United States has been the subject of extensive prior investigation; however, the extent of slip at the southern portion of the fault remains unconstrained. In this study, we use lidar to map terraces and lacustrine landforms in the Obion River valley and investigate apparent broad folding resulting from slip on the buried Reelfoot fault. We compare remote surface mapping results with three auger boreholes in the ∼24 ka Finley terrace and interpret apparent warping as due to tectonic folding and not stratigraphic thickening. We combine our results with historical records of coseismic lake formation that indicate surface deformation dammed the Obion River in the 1812 CE earthquake. Older terraces (deposited at least 35–55 ka) record progressive fold scarps ≥1, ≥2, and ≥8 m high indicating a long record of earthquakes predating the existing paleoseismic record. Broad, distributed folding above the Reelfoot fault into the Obion River valley is consistent with a deep active fault tip along the southern reaches of the fault. Our analyses indicate the entire length of the fault (≥70 km) is capable of rupture and is more consistent with longer rupture scenarios.

Citation

Delano, J. E., Briggs, R. W., Jobe, J. T., Gold, R. D., & Engelhart, S. E. (2021). Quaternary Reelfoot fault deformation in the Obion River valley, Tennessee, USA. Tectonics, 40(8), Article e2019TC005990. https://doi.org/10.1029/2019tc005990

Journal Article Type Article
Acceptance Date Aug 2, 2021
Online Publication Date Aug 30, 2021
Publication Date 2021-08
Deposit Date Aug 11, 2021
Publicly Available Date Mar 28, 2024
Journal Tectonics
Electronic ISSN 1944-9194
Publisher European Geosciences Union
Peer Reviewed Peer Reviewed
Volume 40
Issue 8
Article Number e2019TC005990
DOI https://doi.org/10.1029/2019tc005990

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Copyright Statement
Copyright 2021 American Geophysical Union.
Delano, Jaime E., Briggs, Richard W., Jobe, Jessica Thompson, Gold, Ryan D. & Engelhart, Simon E., (2021), Quaternary Reelfoot fault deformation in the Obion River valley, Tennessee, USA, Tectonics, 40:8, 10.1029/2019TC005990. To view the published open abstract, go to http://dx.doi.org and enter the DOI.





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