Latitude: N 35°27'55"
Longitude: W 119°00'20"
UTM: 11 S 0316477, 3926224
Number of Bench marks: 106
Number of Surveys to 2006: 6
Date of Latest Survey: 29 June 1995
Date of Initial Survey: 19 August 1986
Trespass Permission: Permission to trespass is required.
From Gorman take I-5 North to 99 North, thence to Bakersfield. Go right onto California Street or use 178 east. Go to Chester and turn left. Proceed north to China Grade Loop and turn right. Proceed east about one mile, then turn left into the Chevron-Texaco Gate, and follow Kern Road (north). Turn left onto G and W Road, then left onto Wherehouse Road. Take the first paved road right off at Wherehouse. Then turn left off off the paved road at the base of the transmitter tower hill. You'll be able to see the green metal shed where the line starts.
This box-shaped array was established two miles north of Oildale at the request of Texaco USA to monitor the Kern Front fault which Castle and others (1983) concluded was active. Castle and others (1983) were not able to determine with confidence whether the fault displacement was tectonic or due to subsidence owing to withdrawal of oil and water from the shallow reservoir, but they favored the latter explanation.
Five levelings across the south segment of the array are compared in an accompanying figure for the period August 1986 to June 1995. In that time, 44 mm of displacement have occurred across the fault, for a vertical creep rate of 5 mm/yr., even though several of the wells in the oilfield were shut-in at that time. This rate of displacement is nearly the same rate that Nason and others (1974) found using a tiltbeam at the same site from 1968 to 1972, after which time the tiltbeam was stolen by vandals. A new tiltbeam was erected in November, 1986, and monitored weekly until October 1987. It was resurrected in 2007 and is being monitored as of 2008.
Nine of eleven short fault crossing arrays were releveled on 24 May 2007. The average rate of displacement among the arrays is 5 mm/yr over the 20 years of observations.
Castle, R.O., J.P. Church, R.F. Yerkes and J.C. Manning. 1983. Historical surface deformation near Oildale, California. U.S. Geological Survey Professional Paper 1245, 42 p.
Nason, R.D., F.R. Philippsborn and P.A. Yamashita. 1974. Catalog of creepmeter measurements in central California from 1968 to 1972. U.S. Geological Survey Open File Report 74-31, 387 p.
Up one level
Return to the Title Page.