ASSURING THE LOW BACKGROUND SEISMICITY LEVEL IN SEISMICALLY QUIESCENT BUT POORLY MONITORED AREAS: APPLICATION TO THE SAN JUAN BASIN CARBONSAFE SITE

Geologic carbon storage projects often select seismically quiet areas to mitigate the risk of induced seismicity. Historically, these areas have been overlooked due to low seismicity rates, resulting in limited station coverage and sparse reporting of seismic events. Temporary stations are typically deployed to closely monitor seismic activities, ensuring the detection of any potential small earthquake events, which are harder to detect at a distance but are crucial indicators of hazards and seismogenic faults. However, these temporary measures may not provide a comprehensive overview of seismic activity over a longer time frame. In response, we propose a framework for extending seismic event catalogs beyond temporary monitoring periods, leveraging archived continuous waveform data and various seismic event detection methods. We reprocess data from the US Transportable Array, which offered sparse station coverage across most parts of the Continuous United States for around two years, complemented by data from project-specific temporary stations. We aim to reconcile the observations from two distinct periods and extend their relevance over a decade by employing single station event detection algorithms on the nearest permanent station. The application of our framework is demonstrated on the San Juan Basin CarbonSAFE site, located in northwest New Mexico. Our framework offers new insights into long-term seismic monitoring in quiescent areas.