Image Name                   :  sss96us
Boundaries                   :  Lat 24N to 53N ; Lon 230E to 294E
Color Scale, Upper (Red)     :  -7.7 meters and higher
Color Scale, Lower (Magenta) : -52.8 meters and lower 
Data Max value               :  -7.7 meters
Data Min value               : -52.8 meters
Illuminated from the         :  East 

  This is an image generated from 2'x2' geoid undulations covering the
conterminous United States and surrounding areas.  Some interesting features to 
note about this image are:

  The geoid high, seen as a red spot, is located over the "Yellowstone
hot spot".  While high elevations do contribute to a portion of the geoid
signal here, some geophysicists feel that the geoid high is evidence
of a thermal mantle plume.

  The isolated ridge (visible more from the light/shadowing than from
a different color) seen running from Minnesota to Iowa is associated with
the "mid-continent gravity high".  This gravity high (and subsequently, the
geoid high) is the result of dense masses which lie close to the surface. 
These masses lie in an old rift in the North American plate.
  
  The brightly lit slope in the geoid, off of the east coast, is the
effect of a 4000 meter (~13,000 feet) drop in the bathymetry, demarking the
edge of the continental shelf.

  The few noticably large bumps in the Pacific ocean are caused by massive
seamounts up to 3000 meters (~10,000 feet) in height above the sea floor.

das/dgm 10/18/96