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 electronic seismometer is a state-of-the art instrument. It can accurately record both small local earthquakes and large distant ones. It can also record earth tides and the sonic boom produced by the Space Shuttle as it flies into Edwards Air Force Base.
Public Domain.
