35 Recent advances in our understanding of the New Madrid seismic zone

Thorough understanding of the New Madrid seismic zone will require integration of observations relating to surface features, the crust and the upper mantle. All contributions are welcomed.

Wednesday, 11 March 2026
8:30 AM - 12:00 PM
RCC, 104

Temporal Seismicity and Moment Release on Faults of the New Madrid Seismic Zone

Paper number: 35-3
Program: Technical Sessions
Time: 9:15 AM – 9:30 AM

Authors

Abstract

The faults of the New Madrid Seismic Zone are primarily defined by the temporal/spatial pattern of network-located seismicity.  We use a catalog of 5600 earthquakes over the years of 1997 to 2025 derived from a joint tomographic inversion of earthquake location and 3D crustal velocity structure to investigate the intricacies of fault geometry and evolution of moment release of New Madrid faults. Seismicity is highly clustered in space and shows new details on the relationship of the intersections of the North fault-East fault-Northern Reelfoot fault and the Axial fault-Northern Reelfoot fault-Southern Reelfoot fault.  The Northern and Southern Reelfoot faults are clearly separated by the cross-cutting Ridgley and Cottonwood Grove faults.  The intersection of the North, East, and Northern Reelfoot faults is a complex triangular volume of faulting where the Reelfoot fault gradually steepens.  The Axial fault twists from near-vertical dip in its central part to a SE dip closer to the intersection with the Reelfoot fault.  Distinct linear clusters occur on the Northern Reelfoot fault that may be in-plane seismicity or represent cross-cutting NE striking, strike-slip faults. Network local magnitudes are converted into moment magnitudes and event moments are summed to infer the temporal development of fault creep with time throughout the fault zone.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411785

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