this is called yardang
YARDANG
craters
It's called a crater.
Caldera.
Fjords
Volcanic crater.
earthworm
A noun formed from a verb indicating an action of state is called a gerund. Gerunds are formed by adding "-ing" to a verb and can function as a noun in a sentence.
Crater
I think the answer is called ripple marks
When a very large volume of magma is erupted, the overlying rocks may collapse. The collapse produces a hole or depression at the surface called a caldera.
Erosional caves are formed by the action of water or wind.
I think you mean a cirque. Cirques form when a glacier carves out a depression in a mountain. It can eventually fill with water to make a lake called a tarn.