St. Louis Area Urban Seismic Hazard Map for 1.0 Second Period Ground Shaking
St. Louis area urban seismic hazard map for 1.0 second period ground shaking. The map shows where we expect that there is 2 percent chance in the next 50 years that earthquake ground shaking will occur at this level or higher and specified relative to the strength of the Earth's gravitational force field (g). The yellow region, corresponds to shaking at roughly 0.4 g (40%g) and indicates higher hazard for the Mississippi River floodplain soft sediments than the surrounding upland areas. The ground motions shown here are those from all estimated future possible earthquake magnitudes at all possible distances. The black polygon outlines the study area which is inset into the 2014 USGS National Seismic Hazard Map showing the greater detail of the new results.