CABALLO Level Line

Latitude: N 34°52'07"
Longitude: W 119°13'02"

Length: 1162.4m
Number of Bench marks: 43

Number of Surveys to 2000: 9
Date of Initial Survey: 11 August 1982
Date of Latest Survey: 17 September 1996

Trespass Permission: None Needed

From Frazier Park, proceed about 17.5 miles west through Lake of the Woods and Pine Mountain past Apache Saddle to a U.S. Forest Service dirt road 9N27 on the north side of the road that leads to Caballo and Marian campgrounds. The line extends through Caballo campground.

This irregular-shaped array crosses a fault-bounded pressure ridge in the San Andreas fault zone, 19 miles west of Frazier Park.

The character of bench mark height changes is different on each side of the San Andreas fault. Bench marks northeast of the fault are Class B rods driven into the canyon alluvium above igneous and metamorphic basement rocks, whereas bench marks southwest of the fault are also Class B rodmarks in crushed and sheared Tertiary sedimentary rocks. Although surveying commenced at this site in 1982, the first indication of bench mark stability is reflected only in the 1986 survey.  The changes among the bench mark heights are on the same order of magnitude as the uncertainties from 1986 to 1996, and indicate that significant changes have not occurred at this site.

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