Wisconsin Earthquakes

Steven Dutch University of Wisconsin - Green Bay

A computer printout from the U.S. Geological Survey lists 19 Wisconsin events and 11 more around Houghton in the Upper Peninsula of Michigan. They are shown in the map at left and the table below. None were large or destructive.

If it looks like the earthquakes are targeting cities, it's because these records (mostly old) are based mostly on felt reports, and the observers tended to be concentrated in cities. Several events plot neatly on the Illinois boundary because the computer listing gave a neatly rounded latitude for a location estimate.

Table of Wisconsin Earthquakes
Year Date Location Magnitude Intensity
1964 October 10 Apostle Islands ? ?
1905 July 27 Houghton, MI ? ?
1906 February 9 Houghton, MI ? ?
1906 April 20 Houghton, MI ? ?
1906 May 25 Houghton, MI ? ?
1906 May 26 Houghton, MI ? ?
1906 September 11 Houghton, MI ? ?
1909 January 23 Houghton, MI ? ?
1915 March 3 Houghton, MI ? ?
October 4 Houghton, MI ? ?
1918 October 1 Houghton, MI ? ?
1943 February 9 Athelstane 3.2 III
1905 March 13 Marinette ? ?
1907 January 10 Marinette 4.2 V
1922 July 7 Fond du Lac 4.2 V
1957 January 8 Waupun 3.8 IV
1956 July 18 Lake Church 3.8 IV
1906 April 22 Milwaukee ? III
1906 April 24 Milwaukee ? III
1947 May 6 West Allis 4.2 V
1909 May 26 Beloit 5.3 VIII
1933 December 6 SE Dane County 3.8 IV
1914 October 7 Madison 3.8 IV
1916 May 31 Madison 3.0 II
1931 October 18 Madison 3.2 III
1907 November 20 SW Green County 3.8 IV
1907 November 28 SW Green County 3.8 IV
1948 January 15 Sauk City 4.0 V
1938 November 7 Extreme SW Corner ? ?

Earthquake History of the United States, U.S. Geological Survey Publication 41-1 (1982 edition) lists no Wisconsin earthquakes but lists quite a few out-of-state events as being felt in Wisconsin. Some that plot on the borders of Wisconsin are on the above map but are listed under Michigan or Illinois. In recent years, the most common source of Wisconsin felt reports has been earthquakes in southern Illinois (related to the New Madrid earthquake area) that were felt in tall buildings in Milwaukee.

Seismicity of the United States 1568-1989 (U.S. Geological Survey Professional Paper 1527) also lists no earthquakes for Wisconsin (only Iowa and North Dakota also have no listings). This publication covers only earthquakes of magnitude 4 and above, however. It describes the Houghton event of January, 1909 as due to geological instability due to mining and the cluster of events in that area may all have a similar origin.

The status of the earthquakes on the map is unclear. Considering the fuzziness of the record and the lack of recent events, there is some reason to question how many of these events were real earthquakes. Some may have been real, some may have been quarry collapses or blasts. There is a significant possibility that there have been no earthquakes centered in Wisconsin in recorded history.

Out-of-State Earthquakes Reported felt in Wisconsin
Year Date Location Remarks
1663 February 5 St. Lawrence Valley Felt by French missionaries in Wisconsin
1886 August 31 Charleston, South Carolina Famous Great Earthquake
1909 May 26 Illinois Border Plotted on Map
1909 September 27 Western Indiana
1912 January 2 Northern Illinois
1917 April 9 Eastern Missouri
1925 February 28 St. Lawrence Valley Magnitude 7 Event
1935 November 1 Northeastern Ontario
1937 March 2 Western Ohio
1937 March 8 Western Ohio
1939 November 23 Southern Illinois
1947 August 9 South-Central Michigan
1968 November 9 Southern Illinois
1972 September 15 Northern Illinois
1974 April 3 Southern Illinois
1987 June 10 Northern Illinois

Cryogenic Earthquakes

Cryogenic earthquakes are disturbances related to ground freezing. They can occur when expansion of ice in freezing ground causes ice and already frozen soil to rupture, or when thawing releases pent-up stresses in still-frozen ground. They are not related to any deep tectonic forces within the crust. They rarely cause damage except perhaps at the rupture itself, and are usually felt over a radius of a few hundred yards at most. Because they occur sporadically, are not related to crustal faults, and are felt over such small areas, there is little data on them.

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Created 12 Sept 1997, Last Update 3 May 1999