Integrated Seismic Monitoring During 2025 Reservoir Stimulations at the Newberry EGS Field, Oregon

Abstract

We present the recent effort of the seismic monitoring system at the Newberry Enhanced Geothermal System (EGS) site. The network comprises eight borehole sensors reaching depths of up to 300 m—six legacy 2 Hz geophones (NN07, NN09, NN17, NN19, NN21, NN24) that have been continuously operational since 2012, and two broadband accelerometers (NN18 and NN32) added in 2023 to extend the frequency bandwidth and dynamic range. Data from all sensors are streamed in near real time to the EarthScope Data Management Center (DMC), where they are publicly accessible. Additional regional coverage is provided by nearby stations operated by the University of Washington’s Pacific Northwest Seismic Network (PNSN) and the USGS Cascades Volcano Observatory (CVO). All seismic data are processed in real time using LBNL’s automated detection and analysis pipeline, which identifies, locates, and estimates magnitudes of induced events associated with injection activities at the Newberry site. To enhance spatial and temporal resolution during reservoir stimulation, we also deploy borehole distributed acoustic sensing (DAS) and a surface nodal network consisting of 90 nodes. We analyze seismic signals from two 2025 stimulations (January and August) and compare them with the 2012 and 2014 experiments. Although the 2025 campaigns generated fewer detectable seismic events, the DAS captures coherent P and S wave propagation, which are useful to locate the events. Because the surface stations do not record clear wavefields due to their signal-to-noise ratio, the earthquake size is expected to be much smaller than 2012 and 2014 stimulations.