SPATIAL AND TEMPORAL ANALYSIS OF CENTRAL GREAT PLAINS SEISMICITY

Midcontinent seismicity presents an uncertain level of hazard to people and infrastructure. While the causes behind intraplate earthquakes in the Central Great Plains region of South Dakota, Nebraska, and Kansas are not fully understood, potential factors of seismicity include the interplay of underlying tectonic structures, regional stresses, and oil production. This project analyzes seismic data collected from the Incorporated Research Institutions for Seismology (IRIS) and other historic data including South Dakota, Kansas, and Nebraska Geological Surveys, to identify and quantify earthquake clusters. A point density analysis of 926 earthquake events shows clusters that can be associated with the Colorado Lineament, Nemaha Ridge, and oil production. Temporal animation of the events along with magnitude-weighted cluster analysis will be conducted to study changes in identified clusters. Preliminary anisotropy analysis appears to have a preferential orientation of NE-SW, which is consistent with region stresses and/or underlying structural features. This project could help understand spatial and temporal distribution of midcontinent seismic activity.