AGU: Geophysical Research Letters

 

Editors' Highlight

Intraplate seismicity in the central Mississippi River Valley

During the winter of 1811–1812, large earthquakes occurred in the central Mississippi River Valley along the New Madrid seismic zone. Noting that these earthquakes are unprecedented in the historical record of seismicity within stable continental plate interiors, Forte et al. (2007) analyzed viscous flow models of the mantle based on high-resolution seismic tomography to understand the driving mechanisms of these unique earthquakes. They found that remnants of the ancient Farallon plate, a subducting slab that was completely swallowed up nearly 70 million years ago under the western North American continental margin, continue to descend into the deep mantle beneath central North America. This descent induces highly localized mantle flow directly below the New Madrid seismic zone and downward toward the Earth's deep interior. The authors hypothesized that this flow can strain the overlying crust, causing seismic ruptures. Their results not only reveal a possible new driving mechanism for intraplate seismicity, but also shed light on present-day seismic hazards faced by residents of the central Mississippi River Valley.

View abstract

View full article (Subscription required)