A large-N nodal array to study the structure and magmatic-tectonic processes of Kīlauea Volcanic System

During the summer of 2024, a large-scale deployment of 340 SmartSolo IGU-16 3C 5Hz nodal seismometers took place across 116 locations within the the East Rift Zone (ERZ) of Kīlauea volcano, on the Island of Hawaiʻi. Each site housed three instruments to overcome the limited battery capacity of approximately 30 days, allowing the array to operate continously for three months. The array is designed to push developments in high-resolution mantle-to-crust seismic imaging, temporal monitoring, seismicity characterization and fault loading response caused by ascending magma in the ERZ. The recent eruptive events in 2018 and 2020 caused significant changes to Kīlauea’s internal structure, raising new questions about its eruptive processes and the pathways through which magma is transported. During the array's recording period, three magma intrusions accompanied by swarm seismicity and deformation were observed, culminating in an eruption near the Nāpau Crater in the Middle East Rift Zone in September 2024. These events provide compelling evidence that magma has begun re-entering the ERZ after years of absence. Here we provide an overview of the deployment, evaluate the quality of the collected data, and explore the dataset's potential for seismic imaging.We also show first results, including the development of a seismicity catalog generated using state-of-the-art machine learning techniques, setting the stage for velocity inversion studies and other in-depth analyses. The 2-D nodal array offers new, independent constraints that complement previous geophysical investigations in the region, such as magnetotelluric surveys. The combined insights from these datasets are expected to contribute to a broader understanding of Kīlauea’s magmatic system and the changes occurring within its subsurface structure.