Regresar

Distribution and Geometric Parameters of Volcanic Debris Avalanche Deposits

Abstract:

A new database of volcanic debris avalanche deposits (VDADs) from 594 volcanoes in 52 countries has been compiled based on published inventories and our own unpublished data. This work presents an overview of the distribution of VDADs around the world, their sizes, recurrence intervals, and a quantitative characterization of their controlling parameters. Around 50% of the catalogued deposits are located in Japan, the Americas and Russia. Multiple lateral collapses are common at a single volcanic edifice, with a dozen or more events at some volcanoes. The deposits of volcanic debris avalanches are similar to those of non-volcanic rock avalanches (RAs) in terms of shape, deposit morphology and texture. A comparative analysis of the deposit parameters volume, area, drop height and runout length, however, shows that their main difference lies in the maximum volume RAs can typically reach. This is mainly due to differences in source scar geometry. At the same drop height, VDAs can produce larger volumes because their scars are deeper-seated, more bowl-shaped, and extend along longer slopes than is common for rock slopes. Although the new database is still incomplete, this compilation shows great potential for future analyses and emphasizes the importance of strengthening such inventories with more well-studied cases for sound scientific studies and hazard assessments.