New Madrid Not the Only Hot Spot…
Recent earthquakes have indicated that the New Madrid Seismic Zone is not the only ‘hot spot’ for earthquakes in the Central United States. On June 18, 2002, a 5.0 magnitude earthquake struck Evansville, Indiana with an epicenter between Mt. Vernon and West Franklin in Posey County, in an area that is part of the Wabash Valley Seismic Zone. According to the Indiana Geological Survey, while there was minor damage associated with the earthquake, the tremor was a warning to residents of the Wabash Valley Seismic Zone that earthquakes can, and do, strike close to home.
Further demonstrating that the earthquake hazard within the region needs to be addressed, a 5.4 magnitude earthquake struck near Mt. Carmel, Illinois on April 18, 2008. This earthquake was felt in at least 16 states, by more than 40,000 people, according to the USGS. Fortunately, there were no serious injuries or fatalities, but damage was reported in the Illinois, Indiana, and Kentucky.
Increasing Awareness of the Wabash Valley Seismic Zone
The Wabash Valley Seismic Zone is located in Southeastern Illinois and Southwestern Indiana and it is capable of producing M7.0 earthquakes. Since the discovery of this seismic zone, earthquake awareness and preparedness have increased. Residents are seeing that moderate sized earthquakes are not just occurring to the south, but occur right at home and can affect Illinois, Indiana, and Kentucky.
Previous & Prehistoric Earthquakes
Geologists have found liquefaction sites and sand dikes that shows the evidence of prehistoric earthquakes in the region. By examining the size of the dikes and sediment found within the sand dikes, geologists are able to estimate the size of the earthquake it took to create the formations. In the mid-1980’s, geologist Steven Obermeier found a liquefaction formation that was estimated, through carbon dating, to be 6,100 years old. The earthquake that produced the site was estimated to be a magnitude 7.1—such an event today would cause widespread damage and disruption within the Wabash Valley Seismic Zone.
Further Research and Information
Current research is still turning out new evidence of historic earthquakes in the zone. For further information on the Wabash Valley Seismic Zone, browse through the links below.
- Seismic Profiling of Earthquakes in the Wabash Valley Seismic Zone – Indiana Geological Survey
- Earthquakes in Indiana – Indiana Geological Survey
- Earthquakes in Illinois – Illinois Geological Survey