LITTLEROCK EDM Array
Number of Bench marks: 9
Number of Surveys to 1993: 2
Date of Initial Survey: 10 August 1990
Date of Latest Survey: 25 June 1991
Trespass Permission: None needed.
Directions: From Palmdale proceed east and southeast on 138 to the town of Littlerock. Continue east beyond the town to 96 th St. East and turn right. A Pacific Bell su bstation is located on the corner of Hwy 138 and 96 th St. East. Proceed to Fort Tejon Road and turn left, but turn right almost immediately on the first dirt road. Continue south about 200 m until the road comes to a "T" and turn right at the "T". Drive about 0.3 mile and take a left onto a dirt road hea ding south. A level line across the site intersects the dirt road about 30 m before the base of a southeast-trending ridge.
Comments: The EDM array is a spided-webbed, nearfield quadrilateral spanning the San Andreas fault to determine horizontal strain. Bench marks are Class B rod marks driven to refusal and capped with a stainless steel nipple. The leveling array was established where Dr. David Schwartz (US Geological Survey) dug a series of trench es across the fault to determine its paleoseismicity. The initial and subsequent surveys have been done with a Wild TC2000 total station distance meter.
Results: No significant line length changes have occurred between the two surveys.
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