Skip to content

Analysis of lava flow emplacement and morphology using Synthetic Aperture Radar

Edna W. Dualeh 1, Juliet Biggs1, Jemima Gosling1

Abstract

Monitoring and understanding lava flow emplacement and dynamics are critical for mitigating volcanic hazards but traditional ground-based observations are often limited by hazardous conditions or inaccessibility during eruption. Satellite-based Synthetic Aperture Radar (SAR) provides a powerful alternative, with its ability to penetrate clouds and operate day and night, observing ground surface changes. SAR backscatter, is strongly influenced by surface roughness, allowing for examination of flow morphologies, and textures across the flow through time. However, SAR backscatter remains underexploited for monitoring lava flow emplacement and morphology over time. Here, we demonstrate the potential of SAR backscatter for tracking lava flow progression and morphology. By applying pre-processing filters and temporal analysis techniques, we analyse spatial and temporal variations in SAR backscatter. We observed (1) variability in backscatter along lava flows, likely linked to differences in surface roughness, and (2) the ability to map flow progression with high temporal resolutions. For example, at Erta 'Ale Volcano, Ethiopia, we achieved 79% accuracy in flow extent extraction compared to manual inspection, with rougher, ʻAʻā-like surfaces emplaced furthest from vent likely caused by cooling. The observed lava flow extents at Erta 'Ale could not be reproduced using lava flow simulations (Q-LavHa), with reasonable input parameters. This highlights the need for improved model calibrations and the importance of detailed observations to inform flow modelling and hazard assessment. Our findings demonstrate SAR backscatter as a valuable dataset for volcanic monitoring, complementing other remote sensing and ground-based methods, with potential for refining hazard assessment and lava flow modelling.