Fig. 5From: Probabilistic Volcanic Ash Hazard Analysis (PVAHA) I: development of the VAPAH tool for emulating multi-scale volcanic ash fall analysisSchematic representation of logic tree structure adopted for creation of synthetic catalogue of events; Node 1: Eruption column height (1000 - 40000 m); Node 2: Eruption Duration (1–12 h); Node 3: Source term (Plinian, Sub-Plinian, Vulcanian, Strombolian or Violent Strombolian)Back to article page