Bob,
You are dead on the lack of surveying since the 64 earthquake and the notes on the charts attest to it. The amount of uplift in the Montague Island area is impressive. If you go back into the trees off the beach, you can find the pre-64 high tide line back 40 to 50 feet and 6 to 9 feet higher. The trees/alders growing in the old tidal flat are now around 35-40 years old so it is difficult to see from the water. You can imagine what a 6-9 foot uplift does for chart accuracy not to mention for size of the tsunami it generates.
Tom