Geophysical investigations of the Western Ohio-Indiana region. Final report, October 1986--September 1992: Volume 10
- Michigan Univ., Ann Arbor, MI (United States). Dept. of Geological Sciences
Earthquake activity in the Western Ohio-Indiana region has been monitored with a seismograph network consisting of nine stations located in west-central Ohio and four stations located in Indiana. Six local and regional earthquakes have been recorded from October 1990 to September 1992 with magnitudes ranging from 0.6 to 5.0. A total of 36 local and regional earthquakes have been recorded in the past 6-year period (October 1986 to September 1992). Overall a total of 78 local and regional earthquakes have been recorded since the network went into operation in 1977. There was a peak in seismicity in 1986, including the July 12, 1986 St. Marys` event (mb=4.5), followed by an anomalously low level of seismicity for about 2 years. The most unusual feature of the seismicity in the past.year is the occurrence of three earthquakes in Indiana. The locations of the felt earthquakes are scattered across central Indiana; an area that had been aseismic. Analysis of arrival time data accumulated over the past 14 years shows that the Anna region crustal structure is ``slower`` than the average mid-continent crustal structure. This implies that the proposed Keewenawan rift in the Anna region has a different structure than that of other Keewenawan rifts in the mid-continent.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering; Michigan Univ., Ann Arbor, MI (United States). Dept. of Geological Sciences
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- OSTI ID:
- 10125214
- Report Number(s):
- NUREG/CR-3145-Vol.10; ON: TI94007117; TRN: 94:008442
- Resource Relation:
- Other Information: PBD: Jan 1994
- Country of Publication:
- United States
- Language:
- English
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