Pockmark

Pockmarks are crater-shaped scars on a person's face, usually the result of acne and infections such as chicken pox. The word can also be used to refer to a cratered surface, such as that of a moon or the façade of a building.

Geology
May also refer to shallow seabed depressions, typically several tens of metres across and a few metres deep. Generally, they are formed in soft, fine-grained seabed sediments by the escape of fluids (gas or water, but mainly methane) into the water column. ("Pockmarks in the UK sector of the North Sea", by A G Judd, August 2001). As mud volcanoes in land, pockmarks in sea bottom can be associated with earthquake areas. Many scientists suggest monitoring gas emissions and activity from seabed pockmarks because they can be suitable to predict strong earthquakes, saving life.