Seismic Sciences

Seismic Sciences Background

Fault zones in the vicinity of Paducah

Fault Zones in the vicinity of Paducah and the PGDP.
PGDP is located under the "A" in the "FAC"

Far western Kentucky lies within the northeastern extent of the New Madrid Seismic Zone (NMSZ), an area that holds intrigue for historians, geologists, geophysicists, engineers, seismologists and paleoseismologists. New Madrid, Missouri sits astride one of the notable great bends in the Mississippi River, Kentucky Bend.  New Madrid also marks the epicenter of the Great New Madrid Earthquakes of 1811-12.  More than 1,000 earthquakes occurred during those 2 years with the strongest up to magnitude 8.  The ground liquefied, sand boiled to the surface, the mighty Mississippi flowed backwards and the bootheel of Kentucky, across the river from New Madrid, raised and fell depending upon where you were standing.  The largest earthquakes of 1811-12 remain the strongest earthquakes to have occurred in the US away from plate margin subduction zones.

Seismic joints were added to Enrichment Process piping in 1988 as part of a system seismic safety upgrade

Seismic joints were added to Enrichment Process piping
in 1988 as part of a system seismic safety upgrade

The Paducah Gaseous Diffusion Plant (PGDP) and the city of Paducah are located 55+ miles northeast of New Madrid, Mo. and straddle 3 known seismic zones: the Wabash Valley Seismic Zone (WVSZ), Fluorspar Area Fault Complex (FAC or FAFC) and the NMSZ (FIGURE 2.C.4-1).  The FAC, which is the zone in closest proximity to the PGDP, has not been active in the last 55,000 years. Portions of the WVSZ have been active in the last 6,000 years and the NMSZ remains active today.

For public officials, engineers, seismic scientists, and local citizens, intrigue may be replaced by the challenges of defining and understanding the history and occurrence of earthquakes in the region, their likelihood of recurrence, and the bedrock to surface response at given locations. Defensible and actionable characterization of the seismic hazards and resultant risks inherent to specific locations remain a challenge for all, in particular, the technical and regulatory community.

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