Impact Craters

Part I - Crater Types and Features

Large Impact Craters

Large craters tend to be so large that the centers will smooth over due to the rebounding of the surface, leaving only a crater rim and material ejected from the crater surrounding it. Enormous craters are often called impact basins, which tend to have several concentric rings. Due to the size of the impact that produces the largest craters, there are often secondary craters around them.

Here are some examples of large craters, mainly impact basins. Click on the picture to see a larger image.

Orientale Basin - the Moon

Schroedinger Basin flyover movie - The Moon

Rachmaninoff Basin - Mercury

Raditladi Basin - Mercury

Medium Craters

This type of crater will, occasionally, have central peaks where the surface has rebounded. They can also have relatively smooth, flat crater floors that are a significant part of their interior, apart from the central peak. Some of the central peaks can expand outward and have a ring structure. Along the crater walls, there can also be structures known as terracing, where material has slipped into the crater in stages and formed complex layers. Many of these craters are also referred to as complex craters due to the diverse structures within them.

Here are some examples of medium craters, mainly complex craters. Click on the picture to see a larger image.

Tycho crater - the Moon

An angled view of Aristarchus crater - The Moon

Balanchine crater - Mercury

Eminescu crater - Mercury. Coloring is not natural but is used to detect certain minerals

Small Craters

These are fairly simple, typically a bowl shape with a smooth, curved interior for the most part. In some cases, material may slide down to the center, creating a flat surface, similar to a curved bowl partly filled with liquids or small objects.

Here are some examples of small craters, and images showing the difference between small and medium craters. Click on the picture to see a larger image.

Linne Crater - the Moon

Bruno Crater - The Moon. The image is tilted to reveal the material that has accumulated in the crater's center.

A comparison of the simple/small and complex/medium craters

Profiles of the three crater types

Crater Danilova Radar image below on the left, feature identification map on the right.

Crater Yablochkina Radar image below on the left, feature identification map on the right.

Part II - Craters Features On Different Worlds

Earth Craters

Click on the picture to see a larger version. You'll want to identify the type of crater feature that is pointed out or circled.

Barringer Crater

Wolfe Creek Crater

Mars Craters

Click on the picture to see a larger version. You'll want to identify the type of crater feature that is pointed out or circled.

Unnamed Mars crater

Mojave Crater

Mercury Craters

Click on the picture to see a larger version. You'll want to identify the type of crater feature that is pointed out or circled.

Spitteler crater

Kuiper Crater, all features indicated are the same (and there are also many more in the picture that aren't pointed out)