This type of vintage silver belt was made in Southeast Asia from the 1930s through 1970s and is usually referred to as Siam Silver. The back of the buckle has an unreadable mark or logo and a stamped hallmark (last photo). The belt could be anything from 800 silver to sterling but it's definitely not plated.

The belt is 32 inches long by about 1-1/4" wide and has 24 S-scroll panel links, plus the ornate engraved oval buckle. In excellent condition with no damage. The belt is cleaner and shinier than my photos indicate due to poor lighting the stormy day I took the pictures.