CAR HILL Level Line

Latitude: N 35°53'05"
Longitude: W 120°25'31"

Length: 751.9m
Number of Bench marks: 8

Number of Surveys to 2000: 7
Date of Initial Survey: 23 August 1987
Date of Latest Survey: 23 September 1996

Trespass Permission: Much of the line is on private property behind a locked gate. Contact U.S. Geological Survey

From the Parkfield Bridge, proceed southeast 1.2 miles on Cholame Road to a gate on the north side of the road. The line begins at a metal stake by the gate and follows the road up Car Hill and to Halliburton Ranch.
From Highway 46: Drive northwest 13.6 miles on Cholame Road to the gate.

This leveling array was established in 1982 by John Estrem of the U.S. Geological Survey across the San Andreas fault at Car Hill, about 1.5 miles SSE of Parkfield. A spur may be run to the top of Car Hill from bench mark KH03.

From 1987 to 1992 the bench marks maintained their positions reasonably well. The 1996 survey is perplexing, unless one asserts that the four most aberrant bench marks are unstable, the remainder are stable, and no significant changes have occurred in 9 years at the site.


Sylvester, A. G., 1995. Nearfield vertical displacement in the creeping segment of the San Andreas fault, central California, 1975 to 1994. Tectonophysics 247, 25-47.

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