Assessment of volcanic hazard has been one of the most pursued goals in volcanology, especially for volcanoes near densely inhabited areas. A volcanic hazard assessment is the result of a long chain of different analyses, starting from the study of the potential sources of hazardous phenomena to the capability of forecasting and modelling the evolution of the source and the propagation of the hazardous phenomena from source to target. Volcanic hazard may be caused by a long series of phenomena (tephra fall, pyroclastic flows, lava flows, surges, blasts, ballistic, tsunamis, etc.), including phenomena not necessarily happening during volcanic eruptions (e.g., lahars, gas emissions, deformations, earthquakes, etc.). In addition, also the time frame for volcanic hazard analyses may strongly vary, from long-term (years), to short-term (weeks or days) to early warning (during propagation from source to target). In recent times, the paramount importance of uncertainty quantification and of its communication has been recognized in volcanic hazard analyses. In this context, it becomes essential to both constrain the natural variability of the phenomena (e.g., vent position, eruptive size, source evolution, wind distribution, etc.) and increase our knowledge of the studied systems and phenomena. Hazard estimates are critically dependent on the quality of data available and the statistical methods employed. Going beyond the implausibility of forecasting outcomes that are not present in the data, inhomogeneity of the volcanic record(s) can introduce bias and result in incorrectly calculated forecasts and uncertainties. This inhomogeneity can be present in many forms, but a primary concern is the completeness of the records. In general this varies with eruption size and time (increasing in both dimensions) and, when considering aggregated records from multiple volcanoes, in space.
We welcome contributions reporting advances in volcanic hazard assessments. Significant advances in quantification of volcanic hazards may derive from a broad set of studies, spacing from the improvement of data on past events to the development of new input information to constrain the volcanic processes (e.g., from field or space observations, laboratory experiments, etc.), from the development of new statistical procedures to the improvement of the reliability and/or the computational performances of physical models. Emphasis will be given to methods for improving the treatment and the communication of uncertainties, forecasting capability, and current state-of-the-art techniques for evaluating catalogue incompleteness and inhomogeneity, or compensating for these effects in hazard estimation.