Tiny earthquakes revealed a dangerous secret beneath Northern California. Scientists from UC Davis discovered a hidden and complex fault system. The tremors, too weak to feel, exposed the meeting point of the San Andreas fault and the Cascadia subduction zone. This area is one of North America's most dangerous seismic regions.

The research, conducted through January 2026, involved tracking swarms of these minute earthquakes. The faint tremors offered clues about the subsurface structure. The findings challenged previous assumptions about the region's seismic activity.

The discovery prompted a reassessment of earthquake risk models. Experts are now analyzing the new data to refine predictions. Local authorities are reviewing emergency preparedness plans.

The San Andreas fault and Cascadia subduction zone are major tectonic features. Their interaction creates a complex geological environment. This area has the potential to generate significant earthquakes.

Scientists will continue monitoring the region. Further research will focus on understanding the fault system's behavior. The goal is to improve earthquake forecasting and mitigation strategies.