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Oblique view of Van de Graff from Apollo 17 '' NASA  photo''
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274
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S
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1722
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W
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233 km
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40 km
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173
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is an unusual
Lunar formation that has the appearance of two merged
Crater s, approximately in a
Figure-8 shape with no intervening rim separating the two halves. The crater is located on the
Far Side of the
Moon , on the northeast edge of
Mare Ingenii . The
Birkeland Crater is attached to the southeast rim, nestling against the slightly narrower "waist" of the formation. To the north is the
Aitken Crater , and
Nassau Crater lies to the east.
The outer rim has some terracing along the southwest wall, but is generally in a worn and eroded state. A pair of craterlets overlay the southeast rim, next to Birkeland crater. There are also several small craters on the interior floor of Van de Graaff. The southwest section has a central peak, while the northeast floor is slightly smoother in form.
Orbital studies of the Moon have demonstrated that there is a local
Magnetic Field in the vicinity of this formation that is stronger than the natural lunar field. This is most likely an indication of
Volcanic rock underneath the surface. The crater also has a slightly higher concentration of
Radioactive materials than is typical for the lunar surface.
The crater walls in the vicinity of Van de Graff display an unusual grooved texture. This region lies at the
Antipode of the
Mare Imbrium impact site, and it is thought that powerful
Seismic Wave s from this event converged at this point. Most likely this energy created the grooved appearance as the tremors triggered
Landslide s, although the grooves may also have been formed by deposited clumps of ''ejecta'' from the impact.
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 Van de Graaff crater.
