Abstract

The floor of deep summit craters is often obscured, hindering monitoring and limiting understanding of the dynamic processes within it. At Lascar Volcano, a sudden eruption in December 2022 was accompanied by lava emplacement. We employed satellite and drone imagery to generate high-resolution point clouds, optical and thermal orthomosaics through photogrammetry. Quantitative morphological analysis revealed an initial crater floor uplift from lava extrusion, followed by rapid subsidence that reduced nearly half the volume and formed a central funnel-shaped depression. To investigate surface deformation linked to internal structure evolution, we experimentally simulate lava dome extrusion and subsidence in a scaled 3D-printed mold. The analogue experiments reproduced a funnel-shaped structure consistent with satellite observations and demonstrated the extrusion along divergent faults followed by piston-like subsidence accommodated along convergent faults. The structural pattern constrains underlying conduit geometry and provides insights into dome emplacement dynamics and magma withdrawal mechanisms in upper conduits. © The Author(s) 2025.