Geophysical investigations of the Western Ohio-Indiana region. Annual report, October 1983-September 1984. Volume 3
Earthquake activity in the Western Ohio-Indiana region has been monitored with a precision seismograph network consisting of nine stations located in west-central Ohio and four stations sited in Indiana. Twelve local and near-regional earthquakes have been recorded and located during this report period, ranging in magnitude from 0.3 to 4.0 m/sub blg/. An event which occurred on January 14, 1984 in Toledo, Ohio and two events on July 28 and August 29, 1984 near Terre Haute, Indiana were felt. Only minor damage was reported from these events. Of the twelve events, four occurred in the center of the Ohio array, three occurred near the city of Toledo, Ohio, four occurred in Indiana (including one on the Indiana-Illinois border), and one was located near Chicago, Illinois. Teleseismic P-wave residuals have been updated and evaluated by back projection to various depths in the lower crust. The residuals are found to correspond roughly to magnetic anomalies in the lower crust of Ohio. It is thought that these magnetic anomalies may represent the remains of an ancient rift zone, or perhaps they are the signature of the Grenville Front complex which may cross through this area. 12 refs., 21 figs., 6 tabs.
- Research Organization:
- Michigan Univ., Ann Arbor (USA). Dept. of Geological Sciences
- OSTI ID:
- 5672881
- Report Number(s):
- NUREG/CR-3145-Vol.3; ON: TI85901706
- Resource Relation:
- Other Information: Includes 1 sheet of 24x reduction microfiche
- Country of Publication:
- United States
- Language:
- English
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