New Madrid Seismotectonic Study: activities during fiscal year 1983

Technical Report · Mon Apr 01 04:00:00 EST 1985

OSTI ID:5761199

Buschbach, T C

The New Madrid Seismotectonic Study is a coordinated program of geological, geophysical, and seismological investigations of the area within a 200-mile radius of New Madrid, Missouri. The study is designed to define the structural setting and tectonic history of the area in order to realistically evaluate earthquake risks in the siting of nuclear facilities. Our studies concentrated on defining boundaries of a proposed rift complex in the area, as well as establishing the relationships of the east-west trending fault systems with the northwest-trending faults of the Wabash Valley and New Madrid areas. There were 204 earthquakes located in 1983. In addition, the earthquake swarm in north-central Arkansas continued throughout the year, and 45,000 earthquakes have been recorded there since January, 1982. Current seismic activity in the Anna, Ohio, area appears to be related to the northwest-trending Fort Wayne rift and possibly with the rift's contact with a low-density pluton. Fault studies of the Rough Creek-Shawneetown Fault System showed mostly high-angle normal faults with a master fault that is a high-angle south-dipping reverse fault. Trenching of terrace deposits along the Kentucky River Fault System confirmed some anomalous conditions in terrace deposits previously indicated by electrical resistivity and augering programs. Thermal and chemical data from groundwater in the Mississippi Embayment appear to be useful in localizing deep faults that cut through the aquifers. Early indications from studies of jointing in Indiana are that the direction of major joint sets will be useful in determining regional stress directions. No Quaternary faulting was found in the Indiana or Illinois fault studies.

• Research Organization: Saint Louis Univ., MO (USA)
• OSTI ID: 5761199
• Report Number(s): NUREG/CR-4226; ON: TI85901376
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
ALABAMA
ARKANSAS
EARTHQUAKES
FEDERAL REGION IV
FEDERAL REGION V
FEDERAL REGION VI
FEDERAL REGION VII
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
ILLINOIS
INDIANA
KENTUCKY
MISSOURI
NORTH AMERICA
RIFT ZONES
SEISMIC EVENTS
SEISMICITY
TECTONICS
TENNESSEE
USA