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Seismic Quiescence in the Rome Trough: Implications for Earthquake Potential and Crustal Structure

Description: 

The Rome Trough extends from eastern Kentucky across West Virginia and Pennsylvania into southern New York and forms the easternmost expression of a larger intraplate failed rift system. To characterize earthquake potential of the trough, we used fault, stress, and earthquake data in and near the trough compiled as part of the DOE-funded Midwest Regional Carbon Initiative. Very few earthquakes have occurred inward of the trough’s bounding faults, which contrasts with active earthquake zones abutting the trough to the north and south, including the Eastern Tennessee Seismic Zone (ETSZ). These zones of elevated activity appear to be bounded to the west by a topographic gradient in the Moho that is subparallel to and just east of the Grenville tectonic front and stretches from northern Kentucky to northern Georgia. Thinner crust (~47 km) east of the gradient, excluding the trough, contains the currently active faults while thicker crust (~54 km) to the west is largely quiescent. Thus, the trough appears to bisect crust containing the northern part of a large zone of seismicity, which stretches from southern Ohio to northern Georgia and includes the ETSZ. To understand the dearth of seismicity beneath the trough, we investigated the relationship between stress and major crustal faults. Initially, we evaluated SH_max orientations in the trough, separated into three subregions delineated by large changes in fault trends, each of which is in a strike-slip regime as determined by previous studies. Mean SH_max (σ₁) orientations are offset from the average fault trends in the respective subregions by at most 15°, considerably less than the ideal ~30° needed for faults to slip under typical tectonic conditions. Detailed analyses involving stress inversions are underway to further assess slip susceptibility of Rome Trough faults. Our seismicity observations in and around the trough and the results of the stress inversions and fault slip potential analyses will be presented.

Session: Tectonics and Seismicity of Stable Continental Interiors

Type: Oral

Date: 4/19/2023

Presentation Time: 02:45 PM (local time)

Presenting Author: Seth Carpenter

Student Presenter: No

Invited Presentation: 

Authors