New Madrid, Missouri Sand Blow
In the New Madrid region, sand blows can still be seen on the surface today. Viewed from above, sand blows have circular, elliptical or linear shapes. They can range in size up to tens of meters in width and hundreds of meters in length. In the past, all sand blows were attributed to the 1811-1812 earthquakes. We now know that some of the sand blows pre-date 1811 and formed as the result of prehistoric New Madrid seismic zone earthquakes.