Downhole seismic sources can be used as part of a seismic monitoring effort to track CO₂ plumes during carbon storage activities. This project is developing and field validating low-cost, automated borehole seismic source systems (Figure 1). Current downhole seismic systems are expensive and have reliability issues that this effort is addressing by developing two types of orbital vibrator downhole seismic sources: one for high-resolution cross-well surveys, and one for high-resolution vertical-seismic-profile surveys. Both types of sources are being designed for permanent installation, will be capable of providing continuous active source monitoring, and will be used to improve CO₂ monitoring in the subsurface. Prototypes for each unit are being performance tested/verified at the Lawrence Berkeley National Laboratory’s Geoscience Measurement Facility and at the Richmond Field Station.