Collaborative Research: RAPID: Capturing the Elgin-Lugoff earthquake swarm with a dense nodal array

This RAPID project involves a seismic deployment of 86 Smartsolo 5Hz nodes to the epicenter region of the ongoing Elgin-Lugoff earthquake swarm sequence in South Carolina. This sequence started with a magnitude (M) 3.3 on December 27, 2021, in a region with relatively low background seismicity. This sequence appears to occur in several episodes, sometimes initiated by M 3+ events, and has up to months of gaps in between.

While they occurred along the ancient Eastern Piedmont Fault System, a close examination of the earthquakes reveals that most of the events occurred in between the fault system. At this point, it is still not clear what is the driving force for this earthquake swarm and how long it will last.

This deployment is timely, because this sequence is still ongoing, with no signs of ending soon. In addition, only one station was deployed within a few kilometers of the swarm. Such station distribution is not sufficient enough to provide a detailed high-resolution detection/relocation of microseismicity during an earthquake swarm, which are needed for better deciphering the spatio-temporal evolutions of the swarm sequence and their physical mechanisms.

In addition, the seismic data collected in this deployment will be used to construct a velocity model of the local subsurface structure. Accurate seismic models are crucial particularly for developing ground motion models for seismic hazard assessment and delineating fault

locations. Up to 15 undergraduate/graduate students from both Georgia Tech and University of South Carolina will be involved in the nodal deployment. Data will be made available through the IRIS Data Management Center.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.