level rise has accounted for about 80 percent of the rising shoreline over the past 2-3,000 years 

 (Nixon 1982). 



The rate of sea level rise during the rapid phase beginning 11-12,000 years ago reached as 

 high as 16 mm per year over the Texas coastal shelf and 8 mm per year over the Atlantic coastal 

 shelf (Emery and Uchupi 1972). These values are mean rates determined from regression lines of 

 radiocarbon dating for the period from 1,000 to 15,000 years ago. The Atlantic rate appears 

 typical of most shelf areas of the world. The Texas rate suggests that the shelf itself has subsided 

 relative to most other shelf areas (Emery and Uchupi 1972). 



Results from a variety of radiocarbon studies of peat deposits from present subtidal areas 

 show that during the past 4,000 years, sea level has risen 3-6 m (Emery and Uchupi 1972). In 

 general, during the past several thousand years, eustatic sea level rise has averaged around 1 mm 

 per year. Intervals of no net rise have been deduced from past records, as have periods of more 

 rapid rise. Typical rates as measured at several northeastern tidal stations in the United States are 

 given in Table 4-1. A larger number of tidal station records, broken down regionally and 

 corrected for latitudinal effects, is available in Hicks (1978) for the entire country. These records 

 show that sea level rise over the period 1940-1975 has averaged 1.5 mm per year for the 

 conterminous United States. However, within regions and shorter time periods, deviations from 

 the mean are common. Thus, submergence of the Connecticut coast has averaged 2.6 mm per 

 year from 1940 to 1972, with an anomalous rate of 10 mm per year from 1964 to 1972, a rate 

 approaching late glacial eustatic transgression (Harrison and Bloom 1977). 



TABLE 4-1 



RATES OF NET SEA LEVEL RISE ALONG THE NORTHEAST ATLANTIC COAST 



(from Nixon 1982) 



LONG-TERM RATES (over the past 2-3,000 years) . Data of Bloom and Stuiver 

 (1963), Redfield (1967), Keene (1971), Oldale and 0'Hara (1980), and Rampino 

 and Sanders (1980) . 



Location 



New Hampshire 



Northeastern MA (probably also NH and ME) 



Southeastern MA* 



Cape Code to Virginia 



Connecticut 



Long Island, NY 



SHORT-TERM RATES (1940-1975) from tidal gauge records. From Hicks (1978) 



Location 



Eastport, ME 

 Portland, ME 

 Portsmouth, NH 

 Boston, MA 

 Woods Hole, MA 

 Newport, RI 

 New London , CT 

 New York, NY 



'The published value of 0.01 m/100 yr is a typographical error in Oldale and O'Hara (1980) 

 [Nixon 1982]. 



91 



