Explore the Core

Drilling of the SAFOD core was conducted in one pilot phase and three main phases:

1. Pilot Hole (2002): A 2.2 km vertical hole drilled near the planned SAFOD drill site.

2. Phase 1 (2004) & Phase 2 (2005): The main hole was drilled vertically for the first 1.5 km and then at an angle of approx. 60 degrees from the vertical in order to intercept the full width of the San Andreas Fault near where microearthquakes were clustered (Hole C).

3. Phase 3 (2007): Three lateral sidetracks (Holes E and G) were drilled to intercept actively deforming zones of the San Andreas Fault.