43 Geoinformatics and Data Science (Posters)

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

A preliminary historic (1811-present) earthquake map for Tennessee: obstacles uncovered during compilation

Paper number: 43-1
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

One approach to displaying seismicity aimed at assisting public and government decision making is by plotting historic earthquake epicenters. This provides a graphic representation of seismic activity in a region and can provide an understanding of the relationship between seismicity and the underlying geologic setting. Parts of Tennessee include the New Madrid seismic zone and the East Tennessee seismic zone, two of the most active earthquake zones in the central and eastern United States. To advance seismic hazard analysis and promote community awareness and planning, we compiled data from historic earthquake catalogs from the 1950s through the late 1970s. In addition, we compiled instrument records from 1980 to present (Mm> 2.5) using the USGS Advanced National Seismic System (ANSS) Comprehensive Earthquake Catalog (ComCat).

While developing the map several issues associated with large magnitude interstate earthquakes were observed, demonstrating that data can both illuminate and obscure the epicenter location of historic events.  An 1852 New Madrid earthquake case study highlights the ambiguity of the historic record and how differing reports can influence data. Initial reporting indicates an ambiguous magnitude event in the New Madrid seismic zone temporally coinciding with local reports of building damage in Memphis and a sequence of aftershocks. This event is underreported in catalogs and indicates that the historic data is flawed with respect to understanding the magnitude of the event and that the perceived epicenter was likely mis-located and occurred further south. A Mm 4.1 earthquake event on May 10th, 2025, approximately 21 km southeast of Greenback, Tennessee provides a modern case study of an event that was felt in a multi-state area and highlights how the instrumental catalog provides insight to historic records.

Modern searchability of digitized records makes it possible for the identification of previously unknown events and the addition of data to known events; thereby increasing the accuracy and the overall robustness of catalogs. We outline an approach that incorporates historic data, taking into account old records and modern data search methods. The need to establish best practices and protocol for historical map creation and cataloging represents a long-term issue for the seismic hazard and assessment community.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411741

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.