Multi-ringed basin

A multi-ringed basin (also a multi-ring impact basin) is not a simple bowl-shaped crater, or a peak ring crater, but one containing multiple concentric topographic rings; a multi-ringed basin could be described as a massive impact crater, surrounded by circular chains of mountains. As such, a multi-ring basin slightly resembles a bull's-eye, may have an area of many thousands of square kilometres.
An impact crater of diameter bigger than about is referred to as a "basin".
The structure of multi-ring basins.
In adjacent rings, the ratio of the diameters approximates :1 ≈ 1.41 to 1.
Formation.
To start, a peak ring crater has
A multi-ringed basin has an important difference, which is multiple peak-rings.
In extremely large collisions, following the impact the rebound of the surface can obliterate any trace of the initial impact point. Usually a peak ring crater has a high structure with a terrace, and has slump structures inside of it. There are new theories about the lunar mare called Mare Orientale on Earth's Moon, as to how it formed.
Multi-ring basins are some of the largest, oldest, rarest and least understood of impact craters. There are various theories to explain the formation of multi-ringed basis, however there is currently no consensus.