expansion. A detailed composite study for the United States and a demonstration of 

 the importance of the use of geopotential heights in comparing net changes from 

 s-tations of widely differing latitudes have been given by Hicks (1978). 



Munk and Revelle (1952) created a method entirely independent of sea-level 

 measurements. It is based on variations in the speed of the Earth's rotation and 

 the tilting of its axis of instantaneous rotation. They concluded that their 

 results were not inconsistent with the then accepted value of 1.0 mm per year for 

 the eustatic rise. 



B. Vertical Land Movement 



The vertical land movement component can be determined at a station location by 

 subtracting (algebraically) the eustatic component from the observed relative sea- 

 level series or trend value. The vertical land movement component is, of course, 

 dependent on the accuracy of the eustatic component determination. In practice, 

 regional studies of relative subsidence or emergence are usually undertaken using 

 the best eustatic rate available for anchoring. Wolcott (1972) and Hicks (1972) 

 used this method for the east coast. The results of the latter show the absolute 

 subsidence rate increasing linearly from to 2.14 mm per year from southern Maine 

 to Hampton Roads. Holdahl and Morrison (1974) were particularly successful in using 

 this basic method in conjunction with precise terrestrial relevelings. They concen- 

 trated their study on the gulf coast and Chesapeake Bay. Other regional studies 

 have been made by Fairbridge and Newman (1968), who employed precise terrestrial 

 relevelings, radiocarbon dating, and stratigraphic and archeological evidence in 

 addition to tide-gage series. Their area extended from Chesapeake Bay to Nova 

 Scotia. An example of marked land emergence due to rebound from deglaciation was 

 given by Hicks and Shofnos (1965a) for Glacier Bay, Alaska. 



C. Coastal Processes 



A relative rise in sea level does not cause beach erosion, per se, simply 

 because it doesn't possess any significant kinetic energy in contrast with surf, 

 longshore currents, et cetera. However, rising sea level (relative to the land) is 

 probably the most important single element contributing to the erosion process. The 

 causitive-permissive relationship is best summarized by Rosen (1978) in his quanti- 

 tative study of the effects of sea level on shoreline erosion. The position paper 



