Rapid development and expansion of services from the United States Geological Survey was taking place in the 2000s in terms earthquake monitoring and information dissemination services. A number of products from it and its subdivisions that relay information to the public over the Internet were displayed during the event. An automated system from the National Earthquake Information Center for example, sent an initial notification containing magnitude, depth, and location within two-and-a-half minutes of the mainshock.
Close to the epicenter in Mount Carmel, Illinois, a woman was briefly unable to exit her home due to a collapsed porch and a two-story apartment building was evacuated because of loose and falling bricks. The Edward's County Sheriff's department took reports of minor damage in West Salem. Just across the Wabash River in Indiana, Unit 4 at the Gibson Generating Station automatically shut down due to its vibration sensors, and in Princeton, a woman was cut when a crystal figurine was knocked from a shelf in her home. A man had an eye injury at an unknown location, but medical attention was not sought. In Louisville, Kentucky, some bricks broke off from an older building near downtown. Slightly further away in St. Louis, Missouri, a portion of the South Kingshighway Boulevard viaduct were closed because of loose pieces of concrete, but it was unclear if the debris was related and traffic resumed half an hour later. Several chimneys also collapsed in south St. Louis, and the St. Francis de Sales Oratory reported damage to its steeple, and the Basilica of St. Louis King of France reported small fragments from the mosaic ceiling. Thirty-five thousand people in St. Louis County were without power because the Labadie Power Station went offline due to excessive vibrations. Power was restored by mid-morning. Illinois, Indiana, and Kentucky state highway crews investigated if any roads or bridges were damaged in the area. Cracks were reported on U.S. Route 51 near Cairo at the state's southern tip. No roads were reported to be damaged in Kentucky, but inspections were being conducted in the Louisville, Paducah, and Henderson districts, according to the Kentucky Department of Transportation.
Aftershocks
More than 250 aftershocks ranging in magnitude from.7 to 4.6 were documented in the month following the mainshock, including the largest, which occurred later in the morning. The other stand out shocks in the sequence were the M4 event on April 21, an M4.2 event on April 25, and a M3.4 shock on June 5 CDT.
Response
Many precautionary measures were taken, including several evacuations. All Vincennes University dormitories were evacuated as a precaution, but no damage was discovered and students were allowed to return after about 45 minutes. A coal mine in Gibson County, Indiana, was also evacuated, but miners returned to work shortly afterwards. The Gibson County, Indiana, 9-1-1 system was briefly knocked offline due to a flood of calls, but after about 15 minutes service was restored.
