1968 Illinois Earthquake - Damage

Damage

The earthquake was felt in 23 states and affected a zone of 580,000 square miles (1,500,000 km2). The shaking extended east to Pennsylvania and West Virginia, south to Mississippi and Alabama, north to Toronto, Canada, and west to Oklahoma. Isolated reports were received from Boston, Mobile, Alabama, Pensacola, Florida, southern Ontario, Arkansas, Minnesota, Tennessee, Georgia, Kansas, Ohio, Mississippi, Kentucky, North Carolina, South Carolina, Missouri, West Virginia, Alabama, Nebraska, Iowa, Oklahoma, South Dakota, Pennsylvania, Michigan, and Wisconsin, presumably because of shaking. The worst affected areas were in the general area of Evansville, Indiana, St. Louis, and Chicago, but there was no major damage. There were no deaths; the worst injury was a child knocked unconscious by falling debris outside his home.

Damage was confined to Illinois, Indiana, Kentucky, Tennessee, and south-central Iowa, and largely consisted of fallen chimneys, foundation cracks, collapsed parapets, and overturned tombstones. In one home in Dale, Illinois, near Tuckers Corners and southwest of McLeansboro, the quake cracked interior walls, plaster, and chimneys. Using a type of victim study, the local post office surveyed residents and implemented a field inspection which indicated the strongest shaking (MM VII) took place in the Wabash Valley, Ohio Valley, and other nearby south-central Illinois lowlands. Outside this four-state zone, oscillating objects including cars, chimneys, and the Gateway Arch were reported to authorities.

McLeansboro in particular experienced minor damage over an extensive area. Its local high school reported 19 broken windows in the girls' gymnasium, along with cracked plaster walls. Most of the high school's classrooms sustained fractured walls. The facade of the town's First United Methodist Church was damaged, and a brick and concrete block fell off the top. Hamilton County Courthouse withstood several structural cracks, including one on the ceiling above the judge's seat. The town's residents also reported collapsing chimneys; three chimneys toppled at one home, leading to further damage.

Most of the buildings that experienced chimney damage were 30 to 50 years old. The City Building in Henderson, Kentucky, 50 miles (80 km) east-southeast of the epicenter, sustained considerable structural damage. Moderate damage—including broken chimneys and fractured walls—occurred in towns in south-central Illinois, southwest Indiana, and northwest Kentucky. For instance, a concrete-brick cistern caved in 6.2 miles (10 km) west of Dale.

In Lineville, Iowa, about 80 miles (129 km) south of Des Moines on the Missouri border, the quake was felt as a long shaking. The quake damaged the town's water tower which began to leak 300 US gallons (1,100 L) of water an hour.

Donald Roll correctly predicted the earthquake would have no aftershocks. He later said, "That was kind of a safety valve. The pressure which has been built up has been released." He also described the earthquake as "a very rare occurrence".