A new study used a high-density array of seismic sensors to investigate the structure and behavior of the southern Cascadia forearc. By analyzing data collected from 60 seismometers spaced about 15 km apart, researchers aim to pinpoint the location of the subduction zone, understand the crustal architecture, and differentiate between subduction and San Andreas-related uplift. The findings will help explain why this region experiences frequent slow-slip events and rapid uplift, shedding light on the complex processes at play in subduction zones like Cascadia.