Overview of Research in The New Madrid Seismic Zone

We review the development of understanding of the seismicity and tectonic structure of the New Madrid seismic zone and the upper Mississippi embayment. The broad framework of a failed intracontinental rift with reactivated seismogenic faults was not established until the mid-1970s. By the early 1990s a much more detailed knowledge of the rift and the current seismicity has been gained but fundamental questions remain. The 25 papers of this Special Issue of Seismological Research Letters convey the location of the most recent research front in such diverse fields as seismology, paleoseismology, seismic and potential-field investigation of rift structure, neotectonic deformation, and seismic hazard estimation and response. The new information content of these papers, considered ensemble, is enormous and highlights the tremendous progress made since the 1970s. These current studies, in turn, sharpen the focus on remaining outstanding problems of seismogenesis in the New Madrid seismic zone. We close with a discussion of what we believe will be the important foci of research in the 1990s.