This project is to study how pyroclastic flows cross high mountains (>1000m): whether (1) they are expanded flows and segregate into different parts, or (2) non-expanded flows with high momentum that move over mountains as they do on flat ground. Understanding how flow mechanisms influence runout length and elevations a flow can surmount has major consequences for hazard assessments. The Ito ignimbrite is ideal to study: it (1) crosses high mountains, (2) is well exposed and extensive, and (3) access is easy. Flow direction differences, critical for recognition of the different flow models, will be measured by standard geologic methods (facies analysis, distribution of maximum fragment sizes, fabric analysis) and by anisotropy of magnetic susceptibility. Results should not only provide a better scientific understanding of pyroclastic flow movement, but could also trigger administrative action directly related to saving human lives.
