1947 Wisconsin earthquake

1947 Wisconsin earthquake
Date May 6, 1947 (1947-05-06)
Origin time 15:25 (CST)
Epicenter 43°03′N 87°57′W / 43.05°N 87.95°W / 43.05; -87.95Coordinates: 43°03′N 87°57′W / 43.05°N 87.95°W / 43.05; -87.95
Max. intensity VII (Very strong)

The 1947 Wisconsin earthquake took place on May 6, immediately south of Milwaukee at 15:25 (CST). It was the largest tremor to be historically documented in Wisconsin, but it was not recorded by seismographs.


The area had been previously shaken by the 1909 Wabash River earthquake, causing damage assessed at VII (Very strong) on the Modified Mercalli scale across the Wisconsin-Illinois border. Two earthquakes were also reported in the state in 1912. Shocks in 1919 and 1925, the first from Missouri and the latter from Canada, occurred over enormous zones and affected the entire region, though not seriously. Earthquakes struck Wisconsin again in 1937 and 1939.[1]


The area hardest hit was a 7,770 square kilometres (3,000 sq mi) strip of land in southeastern Wisconsin, while the earthquake was felt over a much more extensive 99 miles (159 km) wide area stretching across the Wisconsin-Illinois border, and to Lake Michigan and Waukesha. Damage consisted of broken windows and fallen porcelain, pots and dishes.[2] The locals' initial impression was that an explosion had taken place. Many evacuated buildings into the streets.[2] Corporate office buildings were emptied of workers.[3] Numerous calls were made local fire departments, police stations and newspapers. Three reports were made to the Milwaukee Fire Department, all describing explosions.[3]

Often described as "sharp", this was the most powerful earthquake to date in Wisconsin's seismological history. The earthquake broke a seismograph at Marquette University.[3] Many hotels, such as the Schroeder Hotel in Milwaukee, were rocked by the tremor. However, the earthquake caused no serious damage or casualties.[3]

See also


  1. "Wisconsin: Earthquake History". United States Geological Survey. January 30, 2009. Archived from the original on 26 March 2009. Retrieved May 6, 2009.
  2. 1 2 "Today in Earthquake History: May 6". United States Geological Survey. January 30, 2009. Retrieved May 6, 2009.
  3. 1 2 3 4 "Sharp Earthquake Rocks Buildings in Milwaukee". Saint Petersburg Times. May 6, 1947. Retrieved May 8, 2009.
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