Disentangling Volcanic Edifice Degradation History using Landscape Evolution Modeling

Volcanic edifices represent a set of dynamic landforms whose morphology encodes the long-term (thousands to millions of years) interaction between construction and erosion. Short-term (years to decades), stochastic volcanic processes cumulatively build topography through both intrusion-based surface uplift and surface-mantling by volcanic deposits. Over longer timescales, these processes compete with climate-based erosive processes that incise and degrade landforms, generating a variety of morphologies from simple, cone-like edifices to complex, non-axisymmetric volcanoes. Despite the importance of disentangling edifice morphologic histories to better discern a regions volcanic record and assess potential hazards, understanding how topographic characteristics of an edifice relates to its transient evolution remains relatively unexplored. Here, we aim to understand how different erosive processes and non-uniform distributions of environmental forcing manifest in edifice morphology by examining volcano degradation histories using the TopoToolbox Landscape Evolution Model. Starting with simplified stratovolcano shapes, we explore the effects of lithology, runoff, and edifice surface uplift on edifice morphologic evolution. Applying metrics previously employed in tectonic settings (e.g., hypsometry, Hacks Law relationship, slope-area, and Chi), we quantify edifice degradation through the lens of radial drainage development and dissection. Furthermore, we derive a series of edifice- and basin-scale non-dimensional metrics that characterize the degree and style of degradation over 100 kyr timescales. We then test the role of spatiotemporal variability of these parameters in driving drainage network development and non-axisymmetric topography. Expanding on our derived non-dimensional model parameters and topography-based metrics, we analyze the impact of temporally-varying and non-uniform landscape evolution forcing parameters on edifice morphology, from which we can better disentangle degradation history from topography. Finally, we compare the results of our numerical models to digital elevation models of natural edifices with known volcanic records from the Andes, Java, and Sumatra to analyze the competition of processes and resulting landform evolution.