9628413 Voight The broad long-term objective of this work is to improve our understanding of magmatic interactions in large-scale volcanic edifices collapse and associated explosive eruptions. magma intrusion may trigger large-scale edifice failure. Rapid edifice failure may in turn provoke destructive explosive events, including the phenomenon known as the 'directed blast'. This project aims at understanding these interactive processes. The best examples of true directed blasts are found at Mount St. Helens (1980), which has been thoroughly studied, and Bezymianny Volcano (1956), which has been little studied. Therefore the proposed research focuses on the Bezymianny blast deposit, and its relation to the debris avalanche that triggered the blast process. The proposed research builds on recent preliminary field studies at Bezymianny by Belousov and Belousov, and collaborating scientists, which suggest that the Bezymianny blast deposits are not analogous with known pyroclastic surge deposits, with the sole exception of Mount St. Helens. Field work will comprise standard techniques of study of stratigraphic relationships, mapping, sampling, sedimentology, and study of bed forms. Samples will be subject to granulometric analyses and studied with SEM, XRD and microprobe. Temperature data will be established from carbonized wood fragments. Grain size distribution, shapes and compositions of particles, together with field observations, will provide the basis for interpretation of eruption processes. The study is expected to have significant implications on volcanic hazards.
