What fault system has been most studied in the world?

The San Andreas Fault system in California is the most studied fault system in the world. It is a transform fault that marks the boundary between the Pacific and North American tectonic plates. Researchers have extensively examined its geology, seismic activity, and potential for generating large earthquakes, making it a key focus for understanding fault mechanics and earthquake prediction. Its significance has also led to numerous studies on the associated hazards and risk mitigation in populated areas.