The New Madrid earthquakes broke up rock like this section of rock face, which was later filled with sand. This photo, from Mississippi County, Mo., was taken in 1904.
Credit M.L. Fuller (Image 362) / USGS
The earthquakes caused the Mississippi River to overflow its banks. The high water brought sand, which covered up several feet at the base of trees. The trees survived and grew roots into the new sand, which had been washed away by the time this picture was taken in 1904.
The magnitude-5.8 earthquake that rattled the eastern U.S. on Tuesday took everyone — even geologists — by surprise. But even when there are reasons to think an earthquake could be around the corner, scientists still can't make good predictions.
Education secretary Arne Duncan, Gov. Jay Nixon, Homeland Security secretary Janet Napolitano and Congressman Russ Carnahan watch students at Carnahan High School participate in the "Great ShakeOut" earthquake drill.
Governor Jay Nixon, Congressman Russ Carnahan, and two members of President Obama's cabinet - education secretary Arne Duncan and Homeland Security chief Janet Napolitano - watched as the 19 students in Lucy Duffey's class dropped to the ground, covered their heads, and held onto tables in the library.