Zupus is the lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

-flooded remains of a lunar

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

. It is located on a southwestern reach of the Oceanus Procellarum

Oceanus Procellarum

Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Earth's Moon. Its name derives from the old superstition that its appearance during the second quarter heralded bad weather...

, to the northwest of Mare Humorum

Mare Humorum

Mare Humorum is a lunar mare. The impact basin it is located in is 825 kilometers across. It was not sampled by the Apollo program, so a precise age has not been determined. However, geological mapping indicates that it is intermediate in age between the Imbrium and Nectaris Basins, suggesting an...

. To the north-northeast is the flooded crater Billy

Billy (crater)

Billy is a lunar crater that is located at the southern fringes of the Oceanus Procellarum, in the western hemisphere of the Moon. It lies to the southeast of the similar-sized crater Hansteen, and west-southwest of the flooded Letronne....

, and some distance to the southeast is Mersenius

Mersenius (crater)

Mersenius is a lunar crater that is located to the west of the Mare Humorum, in the southwestern part of the Moon. To the southwest is the crater Cavendish, and to the south-southeast lies Liebig. Mersenius is 84 kilometers in diameter and 2.3 kilometers deep...

. A system of faint rille

Rille

Rille is typically used to describe any of the long, narrow depressions in the lunar surface that resemble channels. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length...

s named the Rimae Zupus lie to the northwest, following a course to the north-northwest towards the mare

Lunar mare

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...

.

Little remains of the original formation, and the rim is low and irregular in outline, giving the feature the appearance of a valley. This rim climbs to a maximum height of 1.3 km above the base. The crater Zupus S intrudes upon the eastern rim. A faint ghost crater

Palimpsest

A palimpsest is a manuscript page from a scroll or book from which the text has been scraped off and which can be used again. The word "palimpsest" comes through Latin palimpsēstus from Ancient Greek παλίμψηστος originally compounded from πάλιν and ψάω literally meaning “scraped...

lies in the mare to the northeast. The mare covering the floor of Zupus is darker in hue than the surrounding terrain, making the feature relatively easy for an observer to locate.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Zupus.

Zupus	Latitude	Longitude	Diameter
A	17.2° S	53.5° W	6 km
B	17.6° S	54.3° W	6 km
C	17.3° S	55.1° W	19 km
D	19.7° S	53.4° W	17 km
F	17.3° S	54.0° W	4 km
K	15.7° S	52.1° W	17 km
S	17.0° S	51.3° W	24 km
V	18.2° S	56.3° W	4 km
X	18.9° S	54.9° W	5 km
Y	17.4° S	49.6° W	2 km
Z	18.2° S	50.1° W	3 km