Scientists recently completed a 2.6-mile deep, 8.5-in.diameter bore into a seismically active section of the San Andreas Fault nearParkfield, Calif., midway between Los Angeles and San Francisco. The five-year,$20-million project is a joint venture between Stanford University and the U.S.Geological Survey, funded by the National Science Foundation. Therma-SourceInc., Santa Rosa, Calif., is the general contractor. The borehole, reinforced bysteel and concrete, will house seismic instruments enabling scientists to betterunderstand earthquakes. The hole begins on the Pacific plate just west of thefault, passes through the active earthquake zone and winds up in the NorthAmerican plate three miles east of the fault. A third phase calls for lateralboring that will enable scientists to draw core samples. The project isscheduled to finish in 2008.