Links
- Document: Report (42.7 MB pdf)
- Data Releases:
- USGS data release - Luminescence and radiocarbon data for—Geologic map of the Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles, North Carolina and Virginia, and the epicentral area of the August 9, 2020, Mw 5.1 earthquake in Sparta, NC
- USGS data release - Database for the preliminary geologic map of the Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles, North Carolina and Virginia, and the epicentral area of the August 9, 2020, Mw 5.1 earthquake near Sparta, North Carolina
- NGMDB Index Page: National Geologic Map Database Index Page (html)
- Download citation as: RIS | Dublin Core
Introduction
New bedrock and surficial geologic mapping in the Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles, North Carolina and Virginia, investigates the geologic framework and causative mechanisms of the August 9, 2020, Mw 5.1 earthquake near Sparta, North Carolina. The mapping documents (1) the coseismic surface rupture from the 2020 earthquake and related brittle structures in the bedrock; (2) the fault contact between the western Blue Ridge and eastern Blue Ridge; (3) lithostratigraphy in the Lynchburg Group, Ashe Metamorphic Suite, and Alligator Back Metamorphic Suite; (4) the nature of the contact between the Lynchburg Group, Ashe Metamorphic Suite, and Alligator Back Metamorphic Suite; and (5) surficial deposits.
Plain Language Summary
The U.S. Geological Survey and cooperators mapped the bedrock and surficial geology of the Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles in North Carolina and Virginia to provide a detailed geologic framework of the August 9, 2020, magnitude 5.1 earthquake near Sparta, North Carolina. The earthquake produced the first documented faulting that ruptured the surface in the eastern United States. The area is underlain by Precambrian (>541 million years old) igneous and metamorphic rocks in the north and strongly layered metamorphic rocks in the south, separated by a large Paleozoic fault zone (approximately 340 million years old). The regional geologic structural trends (the orientation of faults and rock formations) are aligned northeast to southwest. The surface rupture (Little River fault) from the 2020 earthquake, is mapped for 4 kilometers (~2.5 miles) and cuts across the older geologic structures in the bedrock. Evidence of prior faulting is documented in the Bledsoe Creek valley, where terrace gravels indicate that fault movement occurred before 460,000 years ago.
Suggested Citation
Merschat, A.J., Carter, M.W., Lynn, A.S., Weinmann, B.R., Odom, W.E., McAleer, R.J., Mahan, S.A., Stewart, K.G., Holm-Denoma, C.S., and Crider, E.A., Jr., 2026, Preliminary geologic map of the Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles, North Carolina and Virginia, and the epicentral area of the August 9, 2020, Mw 5.1 earthquake near Sparta, North Carolina: U.S. Geological Survey Open-File Report 2026–1010, 1 sheet, scale 1:24,000, https://doi.org/10.3133/ofr20261010.
ISSN: 2331-1258 (online)
Study Area
Table of Contents
- Introduction
- Discussion
- Description of Map Units
- Correlation of Map Units
- Explanation of Map Symbols
- Acknowledgments
- References Cited
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Preliminary geologic map of the Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles, North Carolina and Virginia, and the epicentral area of the August 9, 2020, Mw 5.1 earthquake near Sparta, North Carolina |
| Series title | Open-File Report |
| Series number | 2026-1010 |
| DOI | 10.3133/ofr20261010 |
| Publication Date | May 04, 2026 |
| Year Published | 2026 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Contributing office(s) | Florence Bascom Geoscience Center |
| Description | Report: 1 p.; 2 Data Releases |
| Country | United States |
| State | North Carolina, Virginia |
| Other Geospatial | Sparta East, Sparta West, and parts of the Glade Valley and Whitehead 7.5-minute quadrangles |
| Online Only (Y/N) | Y |
| Additional Online Files (Y/N) | N |