Latitude: N 35°44'52"
Longitude: W 117°45'00"
Length: 832.2m
Number of Bench marks: 24
Number of Surveys to 2000: 9
Date of Initial Survey: 11 July 1983
Date of Latest Survey: 15 January 1996
Trespass Permission: Permission to Trespass on the property bearing
this array is required and must be obtained well in advance of anticipated
work.
Directions:
From Mojave, drive Hwy 395 north and northeast about 44 miles to Hwy 178.
Proceed eastward 13 miles to the entrance of the Naval Weapons Center. Stop
at the Visitor Center to obtain identification badges and for escort to
Geothermal Program office. To r each the surveying site, proceed to Pole
Line Road, thence proceed northeastward and turn left on Water Road. Veer
right at the Range Control Center. Drive 5.9 miles from the Range Control
Center, through the "very low-flying aircraft" zone, and turn lef t on a
dirt road. Drive about 0.5 mile and park between a clump of trees (to the
left) and a trench (to the right). Bench mark S01 is at a fence post by the
clump of trees.
Comments:
This is one of two L-shaped arrays across one of the normal faults evincing
surface rupture following an earthquake swarm in Indian Wells Valley in 1982.
It is located eight miles NNW of Ridgecrest.
Results:
Seven surveys from July 1983 to January 1996 are compared in an accompanying
figure and have height changes of less than 1 mm, which is nearly equal to
the allowable closure error. One may conclude that height changes are minimal
at best or none at least, and there is no evidence of displacement across
the fault following the swarms of earthquakes in the China Lake area fo llowing
the 28 June 1992 Landers earthquake sequence, or following the 1995 earthquake
sequence on the east side of Indian Wells Valley.
References:
Roquemore, G. R., and J. T. Zellmer, 1983. Ground cracking associated with
the 1982 magnitude 5.2 Indian Wells Valley earthquake. California Geology
30 (9), 197-200.
Sylvester, A. G., J. Feltman, L. Hasbargen, T. Bruskotter, D. Korengold,
S. Dougherty, G. Bawden, and L. Mitchell, 1992. Negligible afterslip with
28 June 1992 Landers earthquake and no nearfield triggered slip on southern
San Andreas fault. EOS Transactions, American Geoph ysical Union, v. 73,
380.
Sylvester, A. G., 1993. Investigation of nearfield postseismic slip following
the M W 7.3 Landers earthquake sequence of 28 June 1992, California. Geophysical
Research Letters, in press.
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