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.
This photograph shows the building housing the USGS Suffolk extensometer. Inside, the extensometer extends to a depth of 1,599 feet below groundlevel.
Period of record: 1982-1995; 2016-present
Public Domain.
