The following discussion has been freely abstracted from ESSSO Guidebook 11 (Mojave Desert Region) by Allen Glazner and Bruce Bilodeau, 1980. From the Vista Point, we look out over the Palmdale Reservoir and the Antelope Valley. The reservoir is a sag feature along the San Andreas rift zone. The fault zone is here about one mile wide and extends from the Vista Point to beyond the low-ridge to the north of the reservoir. The last major displacement here was at the time of the Fort Tejon earthquake in 1857, and amounted to some 20 feet (6 meters) of right lateral slip.

The aqueduct before us is the California aqueduct, which brings water from the Feather River in northern California to several districts in southern California.

The ridge extending northwesterly from the low hills on the far side of the reservoir is Portal Ridge, underlain principally by the Pelona Schist of probably Mesozoic age. The dark ridge to the west of us is the Sierra Pelona, also underlain by the Pelona Schist. The Pelona supports little vegetation, and its name, in Spanish, means "bald." Interest in the Palmdale bulge (Castle & others, 1976) has led the U.S. Geological Survey to monitor tilt, strain, fault creep, and water Well radon levels in this area. To the right of the reservoir is located a creepmeter and fault creep survey array. Plans call for installation of a two-color laser distance measuring network in this vicinity.

Return to highway and proceed north.