Map of Deep Structures in Ohio
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Basement Structures in Ohio
This map portrays a number of deep faults and other structures that have been identified by a variety of geologic studies. Some faults are well known, whereas others are speculative. Very few of them are visible at the surface. The Anna, or Fort Wayne, rift in western Ohio is the site of numerous historic earthquakes.
Modified from Division of Geological Survey Digital Chart and Map Series No. 7 (1991) and Digital Map Series PG-23 (2002; click here to download [2.3 MB PDF]).