Carlisle County, Kentucky

GEOLOGIC HAZARDS

There is one mapped concealed fault in Carlisle County. Currently there is no evidence that this fault is active. However, because of the proximity of Carlisle County to the New Madrid Seismic Zone strong earthquake activity is a possibility. Soil creep, slumps, and landslides along steep slopes may occur from erosion or ground motion associated with a strong earthquake. Areas associated with saturated alluvium and other unconsolidated deposits are subject to liquefaction during a strong earthquake.

Alluvium deposits are also subject to flooding. Soils derived from alluvium deposits have a moderate to high shrink swell capacity, which may affect structural foundations and roads. Flood information is available from the Kentucky Division of Water, Flood Plain Management Branch, www.water.ky.gov/floods/

EARTHQUAKE HAZARDS

Peak ground acceleration at the top of rock that will probably occur in the next 500 years in Kentucky

Although we do not know when and where the next major earthquake will occur, we do know that an earthquake will cause damage. Damage severity depends on many factors, such as earthquake magnitude, the distance from the epicenter, and local geology. Information on earthquake effects is obtained by monitoring earthquakes and performing research. Such information is vital for earthquake hazard mitigation and risk reduction.

The most important information for seismic-hazard mitigation and risk reduction is ground-motion hazard. One way of predicting ground-motion hazard is by determining the peak ground acceleration (PGA) that may occur in a particular timeframe. The map above shows the PGA at the top of bedrock that will likely occur within the next 500 years in Kentucky (Street and others, 1996). It shows, as expected, that PGA would be greatest in far western Kentucky near the New Madrid Seismic Zone. Ground-motion hazard maps for the central United States and other areas are available from the U.S. Geological Survey. These maps are used to set general policies on mitigating damage. For example, maps produced by the USGS in 1996 were used to determine seismic design in building codes. For additional information pertaining to earthquake hazards visit the Kentucky Geological Survey website at www.uky.edu/KGS/geologichazards/geologichazards.html

GROUNDWATER

Abundant ground water is available for domestic, irrigation, and industrial uses in Carlisle County from depths of a few feet down to 600 feet. Generally, depth to groundwater is less than 100 feet, except in the uplands of Carlisle County where sufficient groundwater is obtained at depths greater than 100 feet. Yields in some of the deeper wells are greater than 1,000 gallons per minute, which is sufficient for a community or industrial supply.

Water from the thick Mississippi River alluvium is generally hard to very hard. Water from the non-alluvium aquifers is considered soft and slightly acidic with low dissolved solids. Water quality generally is good, except in areas where downward percolation of surface water and fluids from domestic sewage-disposal systems, and other sources of domestic or industrial pollution, have contaminated the aquifer. Groundwater sometimes contains iron and manganese naturally in objectionable amounts from the deeper zones. In some formations with slightly acidic groundwater, a chemical reaction between the acidic groundwater and steel well casing and pump equipment will produce a high iron content in the water which is not naturally occurring. For more information on groundwater in the county, see Carey and Stickney (2001).

THE LAND

Agriculture is a major part of the Carlisle County economy. There are 122,112 acres in Carlisle County and 49,300 of them were planted with either corn or soybeans in 2002 (Kentucky Agriculture Statistics 2002--2003). Photo courtesy of Jerry McIntosh, U.S. Department of Agriculture--Natural Resources Conservation Service.

Approximately 40 chicken houses are in Carlisle County. Each house holds about 27,000 birds. Chicken litter associated with these operations is used as a substitute for synthetic fertilizers on row crop fields. Photo by Glynn Beck, Kentucky Geological Survey.

An abandoned hog lagoon is being pumped to utilize the nutrient-rich waste water on nearby row crops. To control runoff of the waste water, the lagoon can only be pumped during certain times of the year. Photo by Glynn Beck, Kentucky Geological Survey.

RESOURCES

MeadWestvaco has a fine grade paper mill in Ballard County, which uses the bottomlands in Carlisle County to grow cottonwood and sycamore trees for paper production. MeadWestvaco owns approximately 3,500 acres in Carlisle County. Photo by Glynn Beck, Kentucky Geological Survey.

The new Burkley Boat Ramp will make the Mississippi River more accessible to residents of Carlisle County. Ramp construction is a cooperative effort between the U.S. Army Corps of Engineers, Kentucky Department of Fish and Wildlife, and Carlisle County. Photo by Glynn Beck, Kentucky Geological Survey.