Statistical sedimentary aspects of collapsed volcanic edifices along Pacific subduction zones

In this study, volcanic debris avalanches along the Pacific Rim Subduction Zone, which represent subsequent hazardous flows, have been compared. Using Google Earth imagery and published data on volcanoes worldwide to characterise the dynamics of mass flow and matrix transformation during glacial and interglacial periods. Stratigraphy and textural variations of the matrix related to sedimentological parameters such as the percentage of matrix, mean grain size, and ratio of matrix sand to gravel contribute to characterising the matrix breccias in relation to the spatio-temporal variability of the mass flow deposits. Different factors such as Quaternary erosion, nival surface conditions, and high-intensity rainfall have been considered related to the transformation of the reworked avalanche deposits into debris flows. This study exhibits that the sedimentary characteristics are influenced by the geomorphological parameters such as profile shape, volcanic area, and slope gradient of the collapsed edifices. This study established several statistical equations. The results exhibit similar correlations between quaternary occurrence, matrix percentage, matrix/gravel ratio, and median grain size. Furthermore, these highlight that the semi-quantitative sedimentological analyses of volcanic avalanche deposits contribute to our understanding of subsequent hazardous flows.