Figure 6

Photograph of south wall of the trench across the small scarp at Rito Seco

View of south wall of the trench across the large scarp at Rito Seco showing the different layers that represent sediment eroded off of ancient fault scarps created by prehistoric earthquakes. Each layer marked in the photograph is associated with a single earthquake and by dating the ages of sediment within these layers, we can broadly reconstruct the history of past earthquakes large enough to rupture the ground on this section of the fault.