Kaiser is a crater in the Noachis quadrangle of Mars, located at 46.6° S and 340.9° W. It is 207 km wide and was named after Frederik Kaiser, a Dutch astronomer (1808–1872). Debris flows have been observed on some of the dunes in this crater. Some researchers believe that they may be caused by liquid water. Liquid water could be stable for short periods of time in the summer in the southern hemisphere of Mars. These gully-like debris flows may be denivation features caused by small amounts of ice melting.