Morphometric evolution through erosion of composite volcanoes of the Sunda Arc, Indonesia

VAN WEES, ROOS; O'HARA, DANIEL; GROSSE, PABLO; KERESZTURI, GABOR; TOURNIGAND, PIERRE-YVES; KERVYN, MATTHIEU

Nueva Orleans

Congreso; American Geophysical Union 2021 Fall Meeting; 2021

Volcano morphology is the result of complex interactions between constructive and destructive phases. The dynamics of eruptive, intrusive and erosive processes are reflected in the shapes of volcanoes today. Quantifying the morphology and degradation patterns of composite volcanoes can provide new insights into the evolution of these landforms and the impact of erosion. Here, we explore arc-scale morphometric patterns of composite volcanoes, deriving new relationships between edifice shape, age and erosion.Using 30 m TanDEM-X digital elevation models, we analyse the morphology of 15 composite volcanoes from the Sunda Arc (Indonesia) with available geochronological constraints to estimate incision rates and geomorphic evolution. We start by extracting standard morphometric parameters of the volcanoes, such as edifice volume, height, ellipticity, irregularity, using the previously-published MORVOLC algorithm, recently adapted to run in MATLAB. We then document a series of new metrics that characterize drainage structures and topology with e.g. Hacks law, channel drainage densities, drainage basin distribution, the minimum eroded volume via a convex hull approach and a newly-developed fractal dimension tool. Afterwards, we combine these morphometrics with age data to examine the evolutionary phases of edifice construction and degradation through time.Correlation analysis of the derived morphometric parameters and comparison between volcanoes of contrasting age highlight that the eroded volume, fractal dimension and the irregularity index increase, and the height/basal width ratio and volume decrease with age. When analyzed and systematically characterized these trends have the potential to be used as a relative age determination tool. The proposed morphometric characterisation paves the way for a comparison among composite volcanoes globally and can bridge the current gap between scaled lab experiments and numerical modelling of volcanic landscape evolution.