The New Madrid Seismic Zone (NMSZ) is known for its history of significant seismic activity, particularly a series of major earthquakes that occurred in the early 19th century (1811-1812). Estimates of the recurrence interval for major earthquakes in this region vary, but many studies suggest they occur approximately every 100 to 500 years. Some research indicates that the largest events might occur with a recurrence interval of about 200 to 300 years, while smaller, yet still significant, earthquakes could happen more frequently.
It's important to note that these estimates can vary based on different geological models and the specific parameters being analyzed. As such, ongoing research and monitoring continue to refine our understanding of seismic risks in the NMSZ.