Land subsidence and sea level rise on the Atlantic Coastal Plain of the United States |
| |
| Authors: | George H Davis |
| |
| Institution: | (1) 10408 Insley Street, 20902 Silver Spring, Maryland |
| |
| Abstract: | Land subsidence due to decline in head in confined aquifers, related to municipal and industrial water pumpage, is widespread
in the Atlantic Coastal Plain. Although not a major engineering problem, subsidence greatly complicates adjustment of precise
leveling and distorts prediction of future sea-level rise. When preconsolidation stress equivalent to about 20 m of head decline
is exceeded compaction of fine-grained sediments of the aquifer system begins, and continues until a new head equilibrium
is attained between fine and coarse units. The ratio subsidence/head decline is quite consistent, ranging from 0.0064 in southeastern
Virginia to 0.0018 at Dover, Delaware and Atlantic City, New Jersey. Higher values are related to the occurrence of montmorillonite
as the predominant clay mineral present. Review of tide gauge records indicates that gauges not affected by land subsidence
or other local secular effects have been sinking relative to sea level since 1940 at rates averaging about 2.5 mm/yr, of which
0.6 mm/yr is ascribed to glacio-isostatic adjustment to unloading of North America resulting from melting of late Pleistocene
glaciers, and about 0.9 mm/yr is ascribed to steric sea-level rise related to ocean warming. The residual 1 mm/yr of relative
sea-level rise is not well understood, but may be related to regional tectonic subsidence of the Atlantic coast. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
