SAFOD as part of Earth Scope has drilled and instrumented a vertical borehole across the San Andreas Fault Zone to a depth of 2,3 km, targeting earthquake source from the San Andreas fault prior to drilling the main hole (MH).  

The array included: 80 stations of P/GSI’s 3c analogue geophones.

8 ½” borehole, 115 °C static temperature, max. depth 2347 m (7112 ft), longest operation: 16 months

Mar. 2004: the array had to be recovered due to an intersection of the MH with the PH trajectory and array failure as well as gas influx in the cable jacket.