The Eastern Tennessee Seismic Zone (ETSZ), also known as the East Tennessee Seismic Zone and the Southern Appalachian Seismic Zone, is a geographic band stretching from northeastern

Alabama (We dare defend our rights) , anthem = "Alabama" , image_map = Alabama in United States.svg , seat = Montgomery , LargestCity = Huntsville , LargestCounty = Baldwin County , LargestMetro = Greater Birmingham , area_total_km2 = 135,765 ...

to southwestern

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

that is subject to frequent small

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

s. The ETSZ is one of the most active earthquake zones in the eastern United States.

Earthquake magnitude

Most earthquakes in the ETSZ are small and are detected only with instruments. A few damaging earthquakes have occurred in the ETSZ; the largest historic earthquakes measured 4.6

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

, occurring in 1973 near

Knoxville, Tennessee Knoxville is a city in and the county seat of Knox County in the U.S. state of Tennessee. As of the 2020 United States census, Knoxville's population was 190,740, making it the largest city in the East Tennessee Grand Division and the state' ...

and April 29, 2003 near Fort Payne, Alabama. Earthquakes large enough to be felt occur approximately once a year in the ETSZ. The

U.S. Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...

estimates that earthquakes as large as magnitude 7.5 are possible in the ETSZ. Events of magnitude 5–6 are estimated to occur once every 200 to 300 years.

Seismic source

The source of seismic activity in the ETSZ is not known. The ETSZ is located far from edge of the

North American continent North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

and represents a mid-continent or intraplate earthquake zone. The known faults in the ETSZ are generally ancient; no known

active fault An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,0 ...

s reach the surface. Research published in 2010 indicates a correlation between the Eastern Tennessee Seismic Zone and the New York-Alabama Lineament and suggests that earthquakes in the seismic zone originate at depth in

metasediment In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment Sediment is a naturally occurring material that is broken down by processes of weathering and e ...

ary

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures a ...

Seismic events

Earthquakes associated with the ETSZ have included: * Irondale, Alabama, earthquake, October 18, 1916 (magnitude 5.1) * 1973

, earthquake (magnitude 4.6) * April 29, 2003 earthquake near Fort Payne, Alabama (magnitude 4.6) *December 12, 2018 earthquake north of Decatur, TN and east of Watts Bar Dam (magnitude 4.4 with smaller aftershocks) * August 9, 2020

south of Sparta, NC (magnitude 5.1 with small aftershocks) * October 31, 2020 earthquake 4 miles north-west of

Greeneville, TN Greeneville is a town in and the county seat of Greene County, Tennessee, United States. The population as of the 2020 census was 15,479. The town was named in honor of Revolutionary War hero Nathanael Greene, and it is the second oldest town i ...

(magnitude 2.1) * February 12, 2021 two earthquakes in the Tri-Cities region. One occurred roughly 5.6 miles north-north east of Richlands, Virginia. (magnitude 2.9) The second occurred a few miles south of Erwin, Tennessee. (magnitude 2.5)

References

External links

Center for Earthquake Research and Information, University Of Memphis
{{coord missing, Tennessee Earthquakes in Tennessee Geology of Alabama Geology of Georgia (U.S. state) Geology of Tennessee Geology of Virginia Seismic zones of the United States

Earthquake magnitude

Seismic source

Seismic events

See also

References

External links