This article describes an interactive holographic visualization of volcanic eruption application for Microsoft HoloLens device. The aim of the project is to use this technology to visualize different eruptive phenomena on an active volcano for public education, emergency training, preparedness planning purposes, and raising awareness among tourists. We have selected La Fossa volcano on Vulcano island (Italy) as a case study and, thus, the application is named HoloVulcano. Unity game engine and Microsoft Visual Studio were used to develop the HoloVulcano augmented/virtual reality visualization application. The current version of HoloVulcano visualizes volcanic phenomena typically associated with unrest (fumaroles) and explosive eruptions (e.g. eruptive plumes, ejection of ballistic blocks, bombs, and pyroclastic density currents). The eruption types are developed based on existing literature using Unity game engine's particle systems component. HoloVulcano is a Microsoft HoloLens device application. Wearing the HoloLens, users can interact with the application through voice, gazing, and gestures and view different volcanic phenomena from different sites and angles on the island. HoloVulcano can be used by emergency managers and teachers for training, emergency exercises, and public educatio