Inman West Fault
Part of the Wabash Valley Fault System
Location
East-central Gallatin County, Illinois (J-7 and pl. 2) and Posey County, Indiana
References
Bristol 1975, Bristol and Treworgy 1979, Nelson and Lumm 1987
Description
These structures were first mapped by Bristol (1975) and acquired their current names from Bristol and Treworgy (1979). They are typical elements of the Wabash Valley Fault System-high-angle normal faults striking slightly east of north. The Inman East Fault is the longest, about 20 miles (32 km), and extends into Indiana. Its displacement, 480 feet (145 m), is the largest of any fault in the Wabash Valley Fault System. The eastern side is downthrown, and the fault bifurcates near its southern end. The Inman Fault is about 9 miles (15 km) long, and the west side is downthrown as much as 300 feet (90 m). The Inman West Fault splits off from the Inman Fault toward the south; the downthrown block between them is the Inman Graben. Nelson and Lumm (1987) determined that the Inman Graben terminates against the north edge of the Shawneetown Fault Zone. Data are inadequate to show whether the Inman East Fault does the same.
Figure(s)
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