The figure is from Eric Calais, Andy Freed, Roy Van Arsdale, and Seth Stein (Nature, 2010), showing 1974-2010 earthquakes from the Center for Earthquake Research and Information (CERI) University of Memphis catalog. The faults are inferred from the seismicity alignments. The Mississippi Embayment is a deep bowl of water-saturated river sediments that are most susceptible to liquefaction.