Crater Vocabulary

BBy studying and recording the number, size and extent of erosion of craters, lunar geologists can determine the ages of difference surface areas on the Moon. By studying all types of craters on Earth and by creating impact craters in laboratories, geologists found that the Moon's creaters are impact craters. Here are some terms scientists use when talking about craters.

raised rim	Rock thrown out of the crater and deposited in a ring-shaped pile at the crater's edge during an impact.
floor	The bowl shaped or flat area of a crater, usually below the surrounding ground level unless filled in with lava
central uplifts	Mountains formed due to the increase and rapid decrease in pressure during an impact. These occur only in the center of craters that are larger than 40 km in diameter.
walls	The walls are usually steep and form the sides of the crater area, coming up from the floor of the crater.
ejecta	The blanket of material surrounding the crater that is thrown out during the impact. Usually these are piles of rocks around the circular hole. Ejecta becomes thinner as you move away from the crater.
rays	The bright streaks starting from a crater and extending away for great distances.
impact crater	Craters formed when objects or impactors smashed into the surface.