1973 Knoxville earthquake

Earthquake in Tennessee, United States 1973 Knoxville earthquake 35.799 N 83.962 W region:US_type:event inline,title Tennessee 1973-11-30 07:48:41 usp00004c7 1973 11 30 yes 02:48:41 EST (UTC-5) 4.7 b y 3.0 km mi 0 on Tennessee, United States 6 w yes 3.4 30+ On 30 November 1973, at 07:48 UTC (02:48 EST), a b4.7 earthquake struck 1 km mi north-east of Alcoa, in the U.S. state of Tennessee.M 4.7 - 1 km NE of Alcoa, Tennessee https://earthquake.usgs.gov/earthquakes/eventpage/usp00004c7/executive 27 May 2024 United States Geological Survey The earthquake was felt 2,100 km2 in the area.G. A. Bollinger C. J. Langer S. T. Harding The eastern Tennessee earthquake sequence of October through December, 1973 https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/66/2/525/117537/The-eastern-Tennessee-earthquake-sequence-of Bulletin of the Seismological Society of America It was the most powerful known earthquake generated by the Eastern Tennessee seismic zone. Tectonic setting Eastern Tennessee seismic zone The Eastern Tennessee seismic zone is located far from edge of the North American Plate and represents a mid-continent or intraplate earthquake zone. The known faults in the Eastern Tennessee seismic zone are generally ancient; no known active faults reach the surface.13 June 2003 M4.6 Fort Payne, Alabama Earthquake of 29 April 2003 http://www.gsa.state.al.us/gsa/geologichazards/earthquakes/USGSFortPaynePoster.pdf 27 May 2024 Prepared by U.S. Geological Survey National Earthquake Information Center 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 metasedimentary gneiss.Steltenpohl Mark G. Zeitz, Isidore Horton, J. Wright Jr. Daniels, David L. 27 January 2010 New York–Alabama lineament: A buried right-slip fault bordering the Appalachians and mid-continent North America Geology 38 6 571–574 2010Geo....38..571S 10.1130/G30978.1 Earthquake The United States Geological Survey (USGS) reported a moment magnitude of 4.6 and a focal depth of 3.0 km for the earthquake. It had a maximum Modified Mercalli intensity of VI (Strong). A magnitude 3.4 foreshock struck 1 month before the mainshock.M 3.4 - 2 km WSW of Maryville, Tennessee https://earthquake.usgs.gov/earthquakes/eventpage/usp0000406/executive 27 May 2024 United States Geological Survey More than 30 aftershocks were recorded after the mainshock. The focal mechanism of the mainshock indicated primarily dip-slip faulting, but the data were too sparse to accurately define the direction of the motion. However, based on other data (trend of epicenters, vertical distribution of hypocenters, regional in situ stress measurements), a northwest-striking reverse fault is interpreted as the most likely causal fault. A detailed intensity survey revealed a felt area of 65,000 km2 that exhibited a rapid decrease of intensity to the north and unusually low decrease of macroseismic effects to the south. Topographic focusing of seismic energy is suggested by the intensity data for the town of Maryville, Tennessee. References Category:1973 earthquakes Category:Earthquakes in the United States Category:1973 in the United States Category:1973 in Tennessee Category:November 1973 in the United States Category:Knoxville, Tennessee