Longitude: W 119°43'00"
Length: 302.2m
Number of Bench marks: 4
Number of Surveys to 2000: 13
Date of Initial Survey: 2 February 1972
Date of Latest Survey: 16 February 1991
Trespass Permission: City police maintain that the appropriate city offices should be notified beforehand.
Directions:
From Highway 101 in Santa Barbara, exit at the Mission offramp and go south. Turn left on San Andreas, two blocks west of the freeway, and proceed five blocks to Cook Street, which is on the right. Bench mark C01 is in the curb opposite Cook Street on Sa n Andreas.
Comments:
This is a short line that crosses a low hill and the Mesa fault. It was thought that the low hill may be a pressure ridge along the fault, and the purpose of the array is to determine if the hill is rising. The fault was exposed in a construction trench in 1975 about 30 m southwest of the intersection of Cook and San Andreas streets. Bench marks C06 and C07 are PK nails driven into the asphalt street, but they were damaged as of 16 February 1991 and will not give comparable heights to earlier surveys. The section of Cook between San Andreas and Chino has been resurfaced, obliterating the points in that section.
Results:
Six levelings in the period 1977-1991 are compared in an accompanying figure. Fairly substantial height changes have occurred relative to a bench mark in a curb, but the bench marks at each end of the line, which are bronze tablets set in curbs, have changed only 5 mm relative to one another. This suggests that the hill is not growing, and that the fault has no ver tical movement associated with it. The fluctuations from year to year may be blamed on the inadequacy of bench marks in curbs for precision geodesy, damage to them, and probably to fluctuations in the shallow water table.
