How do geologists determine the age of a fault line?

Geologists determine the age of a fault line primarily through relative dating techniques, such as examining the rock layers (stratigraphy) adjacent to the fault and identifying which layers have been displaced. They may also use radiometric dating methods on minerals or rocks within or near the fault to obtain absolute ages. Additionally, the analysis of fault-related features, such as offset river channels or specific geological formations, can provide insights into the timing of fault activity. Combining these approaches allows geologists to establish a more comprehensive timeline of fault development and movement.