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.
Carrara marble block for field test. (a) A pile of abandoned blocks on the Marina di Carrara coast. (b) The selected block with a vertical, visible natural fracture. The vertical yellow arrow shows the side selected for the GPR measurements. (c) Top view of fracture thickness. (d) Front view of fracture thickness. (e) Detail of a metal target embedded near the fracture in the lower part of the block.
