Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits.
 As craters get larger (greater than 10 km in diameter) they usually have a central peak.
The peak is caused by a rebound of the crater floor following the impact.
 Sometimes craters will display layers.
 Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface.
 Hence, craters can show us what lies deep under the surface.

Research published in the journal Icarus has found pits in Zunil Crater that are caused by hot ejecta falling on ground containing ice.
 The pits are formed by heat forming steam that rushes out from groups of pits simultaneously, thereby blowing away from the pit ejecta.
Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits.  As craters get larger (greater than 10 km in diameter) they usually have a central peak. The peak is caused by a rebound of the crater floor following the impact.  Sometimes craters will display layers.  Since the collision that produces a crater is like a powerful explosion, rocks from deep underground are tossed unto the surface.  Hence, craters can show us what lies deep under the surface.
Research published in the journal Icarus has found pits in Zunil Crater that are caused by hot ejecta falling on ground containing ice.  The pits are formed by heat forming steam that rushes out from groups of pits simultaneously, thereby blowing away from the pit ejecta.
Elysium quadrangle