The 1975 Morris earthquake occurred in western Minnesota on July 9 at 14:54:15 UTC, or 9:54 a.m. local time.[2] The strongest instrumentally recorded rupture in the history of the state, it registered at magnitude 4.6 Mn and had a maximum Mercalli intensity of VI (Strong). It was the first earthquake to be recorded on any seismic instrument in the state since 1917. Tremors were felt over much of Minnesota, northern Iowa, and the eastern Dakotas.
Minnesota is not a very tectonically active state but there is at least one fault zone in it, the Great Lakes Tectonic Zone, stretching from Big Stone County and Traverse County to Duluth.[2] Seventeen earthquakes have occurred along the fault, the two largest being the Morris quake and the Staples event of 1917. Plotting of the earthquakes suggests that there may be another hidden fault in the state somewhat adjacent to it.[3]
Damageedit
The earthquake caused moderate damage and was defined as intensity VI on the Mercalli intensity scale. Minor damage to walls and basement foundations was reported around the epicenter in Stevens County. Damage consisted of cracked plaster, falling items, and pictures being knocked off walls. The quake also cracked the foundations of two homes on East Fifth Street in Morris. Many reports included extremely loud "bangs" and "explosions". These sounds led one to man think that a nearby gas plant had exploded.[4] It was the most intense earthquake recorded in the region; had it occurred in a more populated area it may have caused a larger amount of damage.[5]
^ abcdStover, C.W.; Coffman, J.L. (1993), Seismicity of the United States, 1568–1989 (Revised), U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, p. 258
^ abTom Cherveny. . University of Minnesota Morris. Archived from the original on September 6, 2002. Retrieved December 19, 2008.
^Morris Tribune (June 17, 1993). . University of Minnesota Morris. Archived from the original on February 7, 2009. Retrieved December 19, 2008.
1975, morris, earthquake, occurred, western, minnesota, july, local, time, strongest, instrumentally, recorded, rupture, history, state, registered, magnitude, maximum, mercalli, intensity, strong, first, earthquake, recorded, seismic, instrument, state, since. The 1975 Morris earthquake occurred in western Minnesota on July 9 at 14 54 15 UTC or 9 54 a m local time 2 The strongest instrumentally recorded rupture in the history of the state it registered at magnitude 4 6 Mn and had a maximum Mercalli intensity of VI Strong It was the first earthquake to be recorded on any seismic instrument in the state since 1917 Tremors were felt over much of Minnesota northern Iowa and the eastern Dakotas 1975 Morris earthquakeUTC time1975 07 09 14 54 15ISC event726019USGS ANSSComCatLocal dateJuly 9 1975 1975 07 09 Local time9 54Magnitude4 6 Mn 1 Depth5 0 mi 8 km 1 Epicenter45 30 N 96 06 W 45 5 N 96 1 W 45 5 96 1 1 Areas affectedMinnesota United StatesMax intensityMMI VI Strong 1 Contents 1 Setting 2 Damage 3 See also 4 References 5 External linksSetting editMinnesota is not a very tectonically active state but there is at least one fault zone in it the Great Lakes Tectonic Zone stretching from Big Stone County and Traverse County to Duluth 2 Seventeen earthquakes have occurred along the fault the two largest being the Morris quake and the Staples event of 1917 Plotting of the earthquakes suggests that there may be another hidden fault in the state somewhat adjacent to it 3 Damage editThe earthquake caused moderate damage and was defined as intensity VI on the Mercalli intensity scale Minor damage to walls and basement foundations was reported around the epicenter in Stevens County Damage consisted of cracked plaster falling items and pictures being knocked off walls The quake also cracked the foundations of two homes on East Fifth Street in Morris Many reports included extremely loud bangs and explosions These sounds led one to man think that a nearby gas plant had exploded 4 It was the most intense earthquake recorded in the region had it occurred in a more populated area it may have caused a larger amount of damage 5 See also editList of earthquakes in 1975 List of earthquakes in the United StatesReferences edit a b c d Stover C W Coffman J L 1993 Seismicity of the United States 1568 1989 Revised U S Geological Survey Professional Paper 1527 United States Government Printing Office p 258 a b Tom Cherveny Region s earthquake stories sought for educational project University of Minnesota Morris Archived from the original on September 6 2002 Retrieved December 19 2008 Morris Tribune June 17 1993 Background on fault University of Minnesota Morris Archived from the original on February 7 2009 Retrieved December 19 2008 West Central Daily Tribune July 10 1975 Quake Brings Mixed Reactions Locally University of Minnesota Morris Archived from the original on July 7 2007 Retrieved December 19 2008 Morris Tribune July 10 1975 Earthquake Shock Felt In Area University of Minnesota Morris Archived from the original on October 18 2002 Retrieved December 19 2008 External links editThe International Seismological Centre has a bibliography and or authoritative data for this event Today in Earthquake History United States Geological Survey Retrieved from https en wikipedia org w index php title 1975 Morris earthquake amp oldid 1167166916, wikipedia, wiki, book, books, library,
