Longitude: 118°02'47"
Length: 192.0m
Number of Bench marks: 11
Number of Surveys to 2000: 15
Date of Initial Survey: 22 December 1976
Date of Latest Survey: 24 August 1994
Trespass Permission: None needed, but the array is on private land.
Directions:
From Palmdale, proceed east on Hwy 138 about 6 miles, thence south on 47th Street E to Barrel Springs Road. Cross Barrel Springs Road, proceed about 300 m to an indistinct jeep track that goes west up a ridge to the top of the plateau. The level is locat ed where the road flattens out and proceeds southward.
Comments:
This short S-shaped line was established across the Nadeau fault in the San Andreas fault zone in response to reports of fresh cracks in the pavement of 47th Street East, 50 m southeast of t he array. Bench marks LR21 through LR28 also constitute an alignment array.
Results:
Relative to bench marks on the northeast side of the fault, the southwest side has subsided about 3 mm in 12 years. This may be a response to the 1986-91 drought rather tectonic displacement, although the relative displacement coincides with that across t he scarp.
