Understanding Probability, Consequence, and Their Origins:

You've hit upon the core concepts of risk assessment:

Probability:

• Definition: Probability is a measure of how likely an event is to occur. It's expressed as a number between 0 and 1, where 0 means the event is impossible and 1 means it's certain.
• In your example: The probability of a pipeline failure is the chance that it will actually happen, considering factors like its age, maintenance, and surrounding conditions.

Consequence:

• Definition: The consequence is the impact or result of an event happening. It can be positive or negative, but in risk assessment, we focus on negative consequences.
• In your example: The consequence of a pipeline failure near a populated area is the potential for an explosion, fire, loss of life, and property damage.

Origin of Words:

• Hazard: This word has roots in the Arabic word "az-zar, meaning "dice" or "gamble." Over time, it evolved into the English "hazard" to describe a chance or risk.
• Ezzahr: This Arabic word is likely a variation of "az-zar," which can also be spelled "Ezzahr" or "Ezzar." It essentially carries the same meaning as "hazard" in English.
• Probability: This word comes from the Latin "probabilis," meaning "likely." It was first used in the 16th century to describe the degree of likelihood of something happening.

Putting it Together:

The concept of probability helps us quantify the likelihood of a hazard (like a pipeline failure) occurring. The consequence then describes the potential impact of that hazard if it does occur. By understanding both probability and consequence, we can effectively assess and manage risk.

Your example is a great illustration:

• High probability of failure combined with a high-consequence event (explosion near a populated area) signifies a very high risk. This calls for proactive measures to mitigate the risk, such as rigorous inspections, preventative maintenance, and emergency response planning.