Discipline: Ecology Environmental and Earth Sciences
Subcategory: Geosciences and Earth Sciences
Blaine M. Lary - North Carolina Central University
Co-Author(s): Enrico Brandmayr, North Carolina Central University, Durham, NC; Gordana Vlahovic, North Carolina Central University, Durham, NC
The Eastern Tennessee Seismic Zone (ETSZ) is an intraplate region characterized by a northeast-trending belt of seismicity from northeastern Alabama to the Valley and Ridge Province of eastern Tennessee. Second to the New Madrid Seismic Zone, the ETSZ is the most active continental seismic area east of the Rocky Mountains, featuring low-magnitude events mostly concentrated at depths between 8-16 kilometers and the strongest instrumentally recorded earthquake being of Mw 4.6. The origin of seismicity in this area is not fully comprehended, and the lack of exposed faults and expressions of deformation at the surface hamper scientists’ ability to delineate a coherent seismotectonic model. In an attempt to further the understanding of this zone, this study examines drainage networks of watersheds within and outside of the ETSZ, as drainage networks are very sensitive to tectonic activity such as uplift and subsidence. Using Digital Elevation Models (DEMs), morphometric indices are derived and used to quantify surface deformation that is possibly linked to seismicity. This methodology has been utilized in other seismically active areas, such as the Normandy, France intraplate region, where high morphometric index values generally show a correlation with tectonic activity. A previous study examined the average values of hypsometric curves, hypsometric integrals, slope/area relationships, and stream length (SL) indices for each watershed in the ETSZ, but correlation between uplift and morphometric index values remains inconclusive. This study thus expands on past research with methodological improvements, such as reviewing morphometric indices at the DEM pixel level to account for spatial variation within individual watersheds, and calculating morphometric index values for areas outside of the ETSZ as a baseline for the comparison of seismically active and seismically inactive stream networks. Additionally, earthquake data are analyzed as a function of both the number of occurrences as well as the energy released for each event. The goal of this study is to establish if any correlation exists between seismic activity and surface topography, and to assess which surface processes in the ETSZ are related to seismic stress release.
Brandmayr, E., Vlahovic, G. (2016). The upper crust of the Eastern Tennessee Seismic Zone: Insights from potential fields inversion. Tectonophysics, 685. 1-7.
Font, M., D. Amorese, J.L. Lagarde (2010). DEM and GIS analysis of the stream gradient index to evaluate effects of tectonics: The Normandy intraplate area (NW France). Geomorphology, 119. 172-180.
Stearns, C. (2012). DEM analysis of the Eastern Tennessee Seismic Zone (Master?s Thesis). North Carolina Central University, Durham, North Carolina.Abstract for conference.docx
Funder Acknowledgement(s): This work was in part supported by National Science Foundation CREST award HRD-0833184. Any opinions, findings, and conclusions or recommendations expressed in this abstract are those of the authors and do not necessarily reflect the views of the National Science Foundation.
Faculty Advisor: Enrico Brandmayr, firstname.lastname@example.org
Role: I am the primary conductor of this research with support given by my faculty advisors.