Nevado Sabancaya is potentially hazardous because it was active 200 yr ago, and because it is still ice-clad despite its three years of recent activity. In addition, recent tephra-fall deposits on similar volcanoes in this area point to the occurrence of Plinian eruptions during the past 500 yr. The mapped hazard-zones for tephra fallout, pyroclastic flows, lahars, and potentially catastrophic events are portrayed according to three types of behaviour: moderate-magnitude vulcanian activity (eg June 190-December 1993), violent explosive activity, and a potentially paroxysmal Plinian event. -from Authors