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Brief Report for St. Louis-Cape Girardeau liquefaction features (Class A) No. 1030
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citation for this record: Wheeler, R.L., compiler, 2000, Fault number 1030, St. Louis-Cape Girardeau 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 06:20 AM.
| Synopsis | Tuttle and others (1999 #3904) examined sand blows, sand dikes, and sand sills that were found during systematic searches of streams in southeastern Missouri and southwestern Illinois. The search extended approximately 50-90 km west and east of the Mississippi River, between the St. Louis area on the northwest and the Cape Girardeau area on the southeast. Correlation and dating of the liquefaction features remain uncertain. The present interpretation infers an earthquake of estimated moment magnitude M > 6, and perhaps exceeding 7, that occurred approximately 6,500 years ago, roughly 60 km east of St. Louis. If the magnitude of this 6,500-yr-old event is smaller, then there is a corresponding increase in the likelihood that another earthquake of M > 5.2 occurred in or very near St. Louis. A second earthquake caused strong ground shaking in the area during the past 4,000 years.
These liquefaction features are evidence of strong shaking, but they do not identify the specific fault or faults that caused an earthquake or earthquakes. Because individual Quaternary faults remain unidentified, it is not possible to define and measure specific attributes (azimuth, length, dip, etc.) for the St. Louis-Cape Girardeau liquefaction features. |
| County(s) and State(s) | |
| AMS sheet(s) | St. Louis Paducah |
| 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) | 2000 Russell L. Wheeler, U.S. Geological Survey |
