The New Madrid Seismic Zone (NMSZ): a discussion of fault geometry and its use for dynamic rupture simulations

Abstract:

While the future hazard posed by the New Madrid Seismic Zone (NMSZ) is still debated, history has demonstrated that this intraplate seismic zone is capable of producing catastrophic earthquakes such as the notorious 1811-12 sequence. Numerous studies have been conducted to better understand fault geometries, stress state, ground shaking, as well as magnitudes and locations of past events in order to both understand mechanisms controlling large intraplate earthquakes and characterize future seismic hazard. Here, we present our recent efforts in generating a 3D model of the most major faults within the NMSZ, and discuss the process of synthesizing results from various structural and seismic studies. Variations in fault geometry become crucial when considering complex rupture propagation and fault interactions. Therefore, we introduce a model that contains both variable strike and variable dip along the Reelfoot thrust fault as well as connectivity along the major fault structures that are thought to have participated in the 1811-12 sequence. We use our fault geometry to run a series of dynamic rupture experiments to investigate rupture propagation due to nucleation location, the partitioning of slip across the dipping Reelfoot thrust fault, and constrain the maximum magnitude event considering fault connectivity and interaction.