Initiating Event

The event that starts the sequence of events in the event tree. The initiating event is always the first event (column) is the event tree. For a continuously operating system, it is often the event the disrupts normal system operation. For a standby system, it is often an unsatisfactory event or situation that presents itself.

Column

An event in the event tree. By representing an event, a column also represents a step in an event tree sequence.

Branch

The status of the event. Choice for defining a branch are Success, Failure, Null, and User Defined.

Consequences

The outcomes that are expected when a particular sequence of events occurs. In the event tree, consequences are assigned to each terminating branch. The consequences represent what will happen if the event sequence that ends with this terminating event occurs. Consequences are stored in an Event Tree Consequences file. For more information, see Event Tree Consequences Files.

Sequences

The combinations of events that result in the occurrence of a certain set of consequences. The results shown can include success sequences, failure sequences, or both success and failure sequences.