An official website of the United States government
Here's how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Latest Earthquakes | Chat Share
Philadelphia land use, backcast to 1900 and forecast to 2100, an example of the projections work performed at the USGS EROS Center by Research Physical Scientist Terry Sohl.