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.
Weak regions are represented by yellow spheres. The center of each sphere locates at the geological center of each weak region and the diameter the sphere roughly reflects the size of the weak region.
