Tapahtumapuu

Tapahtumapuu is a Finnish term meaning "event tree." In Finnish technical literature it denotes a tree-structured model used to map events and their possible outcomes within a system, process, or narrative.

A typical tapahtumapuu begins with an initiating event at the root and expands into branches that represent subsequent events or conditions. Each branch may carry a probability or condition, and leaves represent final outcomes or end states. Event trees are often used in probabilistic risk assessment and reliability engineering; they are complementary to fault trees, which start from unwanted outcomes and trace back to causes.

Applications include risk analysis of industrial systems (such as nuclear, chemical, and aviation sectors), where event trees help quantify the likelihood of accidents and the effectiveness of safety barriers. In software and product design, the concept appears as modeling sequences of user actions or system events to understand flows and potential error states. In project management or process improvement, tapahtumapuut can visualize cascading events and contingency planning.

See also: event tree, fault tree, hazard analysis. The term is used primarily in Finnish-language texts, reflecting the broader English-language concept of an event tree used across safety analysis, engineering, and systems modeling.