Abstract
We collected rapid-repeat radar data capturing the deformation of the active Halema'uma'u summit lava lake surface on January 19, 2023, an otherwise quiescent period during the January-March 2023 eruption. Radar interferograms were generated every 90 s over a 90-min period of intermittent inflation using a scanning real aperture radar operating at Ku-band (17.4 mm wavelength). This technique allows observation of phenomena at a temporal scale and spatial resolution not previously possible. We model the intrusion as a shallow sill, 10 to 100 m below the lava lake surface. We suggest that frequent intrusions of such small volume pulses of gas-rich magma help to provide the flux of heat and mass necessary to compensate for cooling, outgassing, and recycling of dense degassed magma to deeper levels, sustaining the lava lake during periods of near-steady-state. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00445-025-01847-8.