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.
Visible/near-infrared (VNIR) and mid-infrared (MIR) spectral library composed of twenty natural tephra samples from ten volcanic sources that span a range of compositions and components. The bulk,...
data.gov
An official website of the GSA's Technology Transformation Services