GEOLOGIC HAZARDS
There are several concealed
faults located throughout
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/
A large portion of
EARTHQUAKE HAZARDS
Peak ground acceleration at
the top of rock that will probably occur in the next 500 years in
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
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
This reconstructed and protected bluff,
located just north of Hickman, has been unstable since
the city was founded in 1819.
This bluff, and possibly others in the area,
is highly susceptible to landslides during a strong earthquake. Photo by Glynn
Beck,
GROUNDWATER
In parts of
Abundant groundwater is available
for domestic, irrigation, and industrial uses in
Water from alluvium is generally hard to very
hard with moderate to high levels of dissolved solids. Water from the sand or
gravel, non-alluvium aquifers are 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 naturally-occurring iron and manganese in objectionable amounts from
the deeper zones. In some formations
with slightly acidic groundwater, a chemical reaction between the acidic
groundwater, 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
Most
of
which consists
primarily of steep slopes and narrow ridge tops. The
Photo by
Approximately 40 chicken houses are in
these operations is used as a substitute for synthetic
fertilizers on row crops. Photo by
Agriculture is a major part of the
planted with either
corn or soybeans in 2002 (Kentucky Agriculture Statistics 2002--2003). Photo
courtesy of Jerry McIntosh,
U.S. Department of Agricultural--Natural
Resources Conservation Service.