Geophysical-geological studies of possible extensions of the New Madrid Fault Zone. Annual report for 1983. Volume 2

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

OSTI ID:5926619

Hinze, W J; Braile, L W; Keller, G R; Lidiak, E G

Recent geophysical investigations have shown that the seismicity of the New Madrid, Missouri seismogenic region is correlative with an ancient rift complex suggesting that the anomalous seismicity is the result of the localization of the regional compressive stress pattern by basement structures. Preliminary evidence indicates that this inferred basement rift complex extends beyond the immediate realm of the intense New Madrid region microseismicity. An integrated geophysical/geological research program is being conducted to evaluate the rift complex hypothesis as an explanation for the earthquake activity in the New Madrid area and its extensions, to refine our knowledge of the structure and physical properties of the rift complex, and to investigate the possible northern extensions of the New Madrid Fault zone, especially the possible northeastern connection to the Anna, Ohio seismic region. Investigation of the northeast extension of the New Madrid Rift Complex into eastern Indiana, north of 39/sup 0/N latitude, has focused upon the acquisition and preparation of arrays of gravity and magnetic anomaly data sets. Another possible arm of the New Madrid Rift Complex, the St. Louis Arm, which extends northwesterly from southern Illinois along the Mississippi River to St. Louis, Missouri, is being studied by an integrated geophysical, seismicity and geological investigation. However, during 1983, special emphasis was placed upon integration of gravity and magnetic anomaly data from the Anna, Ohio seismogenic region with basement lithologic and seismicity information to investigate the possible relationship of basement geology to the seismicity of the Anna area. Interpretation of these data indicate the occurrence of several major lithologic/structural features in the crust of the Anna area. Current seismicity in this region appears to be related to an ancient rift structure and possibly its contact with a low density pluton. 18 refs., 37 figs.

• Research Organization: Purdue Univ., Lafayette, IN (USA); Texas Univ., El Paso (USA); Pittsburgh Univ., PA (USA)
• OSTI ID: 5926619
• Report Number(s): NUREG/CR-3174-Vol.2; ON: TI85901341
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ARKANSAS
SEISMICITY
ILLINOIS
INDIANA
KENTUCKY
MISSOURI
OHIO
RIFT ZONES
GEOLOGIC STRUCTURES
TENNESSEE
GRAVITY SURVEYS
MAGNETIC SURVEYS
FEDERAL REGION IV
FEDERAL REGION V
FEDERAL REGION VI
FEDERAL REGION VII
GEOPHYSICAL SURVEYS
NORTH AMERICA
SURVEYS
USA
580201* - Geophysics- Seismology & Tectonics- (1980-1989)