Wednesday, January 20, 2010
Sunday, January 10, 2010
This photograph of the New York City skyline was taken from the top of Bear Mountain in the Hudson Highlands some 40 miles (64 kilometers) due north of the city. It reveals something interesting about the interplay of physical and cultural geography as New York City developed.
Notice how the large, tall buildings are clustered in the Midtown and Wall Street areas while the buildings in "The Village" (Greenwich Village and Chinatown)are smaller and lower. The pattern is not simply a matter of coincidence - it is controlled by the underlying geology of Manhattan Island. The tall, heavy buildings are built where strong, crystalline bedrock is available at the surface to support them. The Village, on the other hand, is underlain by unconsolidated glacial deposits incapable of supporting such massive skyscrapers without extensive and expensive engineering of their foundations.
The annotated Google Earth screen shot to the left here (south is to the TOP of the image)is a "top view" of what you're seeing in the photograph.
The Midtown - Village - Wall Street pattern is also apparent looking east from the New Jersey Turnpike, and you can read more about the development of NYC at this US Geological Survey page.