Phase III occured over for the summer of 2007, involving several multilateral core holes drilled off of the main hole to obtain continuous core within the San Andreas Fault Zone. A pilot hole was drilled at the SAFOD site in 2002 with financial support from the International Continental Scientific Drilling Program (ICDP) and NSF.

More Info

The Parkfield region is the most comprehensively instrumented section of a fault anywhere in the world, and has been the focus of intensive study for the past two decades. Through sampling, down-hole measurements and long-term monitoring directly within the San Andreas fault zone at seismogenic depths, we will learn the composition of fault zone materials and determine the constitutive laws that govern their behavior; measure the stresses that initiate earthquakes and control their propagation; test hypotheses on the roles of high pore fluid pressure and chemical reactions in controlling fault strength and earthquake recurrence; and observe the strain and radiated wave fields in the near field of microearthquakes.

The SAFOD pilot hole is a separate, 2.2-km-deep scientific drilling experiment being carried out at the same surface location planned for SAFOD. This site is ~ 1.8 km SW of the San Andreas fault near Parkfield, CA, on a segment of the fault that moves through a combination of aseismic creep and repeating microearthquakes. It lies just north of the rupture zone of the 1966, magnitude 6 Parkfield earthquake, the most recent in a series of events that have ruptured the fault six times since 1857. The Parkfield region is the most comprehensively instrumented section of a fault anywhere in the world, and has been the focus of intensive study for the past two decades as part of the Parkfield Earthquake Experiment. The pilot hole is a collaborative effort between the International Continental Drilling Program (ICDP), NSF and the U.S. Geological Survey (USGS).