Comparison of precise leveling done on Middleton Island in the Gulf of Alaska in 1966, 1974, and 1975 indicates that between 1974 and 1975 the island was tilting down to the northwest at a rate of 5.0 ± 0.8 μrad/year. The direction of tilt is normal to the axis of the Aleutian Trench 60 km to the southeast. The data are inadequate to determine variations in the rate since the earthquake, but suggest that it has been higher. A simple model for slip on the near-surface projection of the fault surface that ruptured in 1964 suggests that on the order of 212 meters/yr of slip would be required to account for the observed tilt.

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