Trenching in the New Madrid seismic zone

Trenching studies of the San Andreas fault have been of great value to geologists in California for determining not only the prehistoric occurrences of earthquakes on the fault bu also the age of these movements. In the New Madrid seismic zone, U.S Geological Survey scientists have been trenching across suspected faults to try to assess earthquake frequency in the Central U.S. The following photographs document these trenching studies.