EARTHQUAKES IN WISCONSIN ARE RARELY MAJOR EVENTS
By Tom Emery
(Continued from Current Stories page) -
Those quakes struck thirty-six years before Wisconsin attained statehood, and with population sparse among the territory, there was minimal loss of life and property damage.
Fortunately, nothing has matched the New Madrid event in Midwestern history, though there have been some notable shakers, including some detected in Wisconsin. Among them was a quake on Nov. 9, 1968 measuring 5.4 on the Richter scale that was centered in Hamilton County in southern Illinois. Wisconsin was one of 23 states that felt the quake, as residents from LaCrosse to Madison to Milwaukee and points in between noticed some trembling.
Another southern Illinois tremor in November 1939 was felt in Janesville. Similarly, a September 1972 quake in Illinois was felt over eight states, including Wisconsin, where cracks in plaster were recorded in Milton, Kewaskum, and Nashotah. At least one report in Wisconsin was received of leaking pipes caused by that tremor.
Two significant earthquakes centered near Aurora, Illinois on May 26, 1909 and again on Jan. 2, 1912 were both noticed in Wisconsin. The first was felt in Platteville, while the second raised eyebrows from Milwaukee to Madison. The latter city also picked up two shocks from an April 9, 1919 quake in eastern Missouri.
Tremors six days apart near Anna, Ohio in early March 1937 were felt in Milwaukee, while reports of the second tremor were also received in Madison.
Wisconsin sometimes feels the effect from faraway quakes. On Aug. 31, 1886, a severe earthquake hit Charleston, S.C. – a region not known for strong shakers – and caused extensive damage. Residents in Beloit, Janesville, Milwaukee, and many other Wisconsin locales reported moderate trembling, many hundreds of miles from the epicenter.
Similarly, a major quake near the St. Lawrence River in Quebec on Feb. 28, 1925 was picked up from LaCrosse to Milwaukee, while another Canadian shaker on Nov. 1, 1935 was detected in most of the northeast quadrant of the United States, including eastern Wisconsin.
Quakes across the lake in Michigan have spread to Wisconsin. One, in south-central Michigan on Aug. 9, 1947, was detected in Racine, Milwaukee, and Medford.
Three months before, at 4:25 a.m. on May 6, one of the more unnerving quakes in Wisconsin history was centered south of Milwaukee near the shore of Lake Michigan. Buildings shook and windows rattled in a 7,770-square kilometer region of southeastern Wisconsin, from Sheboygan south to the state line and as far inland as Waukesha.
Broken windows were reported in Kenosha, while other areas reported glasses and dishes that had been knocked from shelves. In Milwaukee, a few scared residents raced into the streets, believing that an explosion had occurred.
At 4:37 a.m. on April 18, 2008, an earthquake measuring 5.2 was centered near Mt. Carmel, Ill. and felt as far away as Canada, setting news programs and social media abuzz in Wisconsin and surrounding states. Ironically, it was the 102nd anniversary of the destructive San Francisco quake that cost an estimated 3,000 lives.
The 2008 quake occurred along the Wabash Valley Fault, which has produced most of the recent southern Illinois tremors. In contrast, the more famous New Madrid fault has not produced a significant earthquake in decades.
In 2005, seismologists predicted a 90 percent chance that an earthquake of 6.0 to 7.0 would hit the Midwest again in the next half-century, likely on the Wabash Valley Fault – threatening nearby urban centers like St. Louis, Memphis, and Chicago.
The 2005 finding appears much stronger than wild claims from crack scientist Iben Browning in 1990 that a severe New Madrid earthquake was imminent, which never occurred but left some Midwestern residents terrified of an impending disaster.
Tom Emery is a freelance writer and historical researcher from Carlinville, Ill. He may be reached at 217-710-8392 or firstname.lastname@example.org.