Postearthquake changes in elevation across the Tujunga segment of the San Fernando fault in the period March 1971 to 1973-1974 indicate deformation similar in distribution to, but on a much smaller scale than, the coseismic deformation (the maximum postearthquake uplift is about 60 mm compared to the 2 m of coseismic uplift). The postearthquake elevation change just east of the 1971 rupture is a nearly uniform increase in elevation to the north that reaches about 60 mm at the end of the profile. The postearthquake elevation change across the Sylmar segment of the San Fernando fault is more subdued and apparently in the opposite sense from the coseismic deformation; it may be due to local compaction. The horizontal deformation observed in the period August 1971 to March 1973 across a geodimeter network that spans the San Fernando fault is minor (displacement not more than 10 mm). If the explanation of the observed vertical deformation across the Tujunga segment of the fault is indeed afterslip, the deformation must have occurred chiefly in the period March to August 1971.

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