Latitude: N 35°53'38"
Longitude: W 120°26'32"
Number of Bench marks: 12
Number of Surveys to 2000: 4
Date of Initial Survey: 27 June 1989
Date of Latest Survey: 22 June 1993
Trespass Permission: Ranch is occupied. Permission to trespass is required.
From the bridge at Parkfield, drive northwest on Vineyard Canyon Road 0.6 mile to the Owens Ranch gate (now called Bennett Ranch). The line begins about 100 m north of the gate. The first bench mark (XPK5) may be buried and difficult to find.
The bench marks in this array belong to an alignment that was established by Dr. Jeremy Isenberg to determine the performance of buried pipelines in earthquakes. Only the end bench marks are Class B standard. The remainder are plastic stakes on top of the pipeline.
The three levelings suggest that the northeast side of the fault subsided about 15 mm relative to the southwest side since 1989, but not at the fault trace.
Isenberg, J., E. Richardson, H. Kameda, and M. Sugito, 1990. Pipeline response at Parkfield, CA. to Loma Prieta earthquake. Proceedings of Fourth U.S. National Conference on Earthquake Engineering, vol. 1, 925-933.
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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