Total natural gas rig count in the US (including conventional gas drilling) Shale gas is natural gas that is found trapped within shale formations. Shale gas has become an increasingly important source of natural gas in the United States since the start of this century, and interest has spread to potential gas shales in the rest of the world.
A stressor is a chemical or biological agent, environmental condition, external stimulus or an event that causes stress to an organism.[1]
Stressors are events that cause stress. There are basically 3 types of stressors: 1) Cataclysmic events. Cataclysmic events are events that occur suddenly and usually affect a lot of people simultaneously. An earthquake would be an example of a cataclysmic event. Another example would be a terrorist attack. 2) Personal stressors. Personal stressors are significant life changes such as the death of a close relative, the loss of a job, etc.