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Brief Report for Wabash Valley liquefaction features (Class A) No. 1024
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citation for this record: Obermeier, S.F., and Crone, A.J., compilers, 1994, Fault number 1024, Wabash Valley liquefaction features, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/regional/qfaults, accessed 11/24/2009 06:04 AM.
| Synopsis | Clastic dikes filled with sand and gravel, interpreted to be the result of earthquake-induced liquefaction, occur throughout much of southern Indiana and adjacent parts of Illinois. At least seven and probably eight prehistoric earthquakes have been documented during the Holocene, as well as, at least one during the latest Pleistocene. Nearly all of these liquefaction features originated from earthquakes centered in southern Indiana and Illinois, and not further south in the nearby source region of the great 1811-1812 New Madrid earthquakes.
The recognition of different earthquakes is based mainly on defining limits on the timing of liquefaction features in combination with the regional pattern of liquefaction effects, but some earthquakes have been recognized only by geotechnical testing at sites of liquefaction.
Prehistoric magnitudes were probably on the order of moment magnitude M 7.5, which greatly exceeds the largest historical earthquakes of M 5.5 in the region. The strongest prehistoric earthquakes had epicenters in the vicinity of the lower Wabash Valley, where the valley borders both Indiana and Illinois.
The evidence of Quaternary faulting in the Wabash Valley area is based on the presence of liquefaction features. Liquefaction features are evidence of strong shaking, but they do not identify the specific fault that caused an earthquake. Because individual Quaternary faults remain unidentified, it is not possible to define and measure specific attributes (azimuth, length, dip, etc.) for the Wabash Valley liquefaction features. |
| County(s) and State(s) | |
| AMS sheet(s) | Evansville |
| Physiographic province(s) | |
| Length (km) | 0 km. |
| Average strike | |
| Sense of movement | No data |
| Dip Direction | Unknown |
| Historic earthquake | |
| Most recent prehistoric deformation | Latest Quaternary (<15 ka) |
| Slip-rate category | Insufficient data |
| Date and Compiler(s) | 1994 Steven F. Obermeier, U.S. Geological Survey Anthony J. Crone, U.S. Geological Survey |
