Which term is used to describe an unforeseen event that occurs without human intervention?

The term that best describes an unforeseen event that occurs without human intervention is "Act of God." This phrase is commonly employed in legal, insurance, and contractual contexts to refer to events such as floods, hurricanes, earthquakes, and other natural phenomena that cannot be prevented or controlled by human actions.

"Act of God" specifically highlights the aspect of these events being entirely outside human influence, which is key to understanding their characterization in legal scenarios, especially when determining liability and risk factors in insurance policies.

The other options, while related to unforeseen events, do not capture the same legal and technical nuances. For example, "Force majeure" is a broader legal term that includes not only natural disasters but also other extraordinary circumstances that prevent fulfilling contracts. "Natural disaster" refers specifically to catastrophic events resulting from natural processes, while "Unexpected occurrence" is vague and does not carry the same legal weight or specificity as "Act of God." Thus, the focus on the non-human influence makes "Act of God" the most precise and appropriate term in this context.