Kīlauea Volcano — Caldera Changes (May 23 - 31)

This animated GIF shows a pair of radar amplitude images that were acquired by the Italian Space Agency's Cosmo-SkyMed satellite system. The images illustrate changes to the calderaarea of Kīlauea Volcano that occurred between May 23 at 6:00 p.m. HST and May 31 at 6:00 p.m. HST. The satellite transmits a radar signal at the surface and measures the strength of the return, with bright areas indicating a strong return and dark areas a weak return. Strong returns indicate rough surfaces or slopes that point back at the radar, while weak returns come from smooth surfaces or slopes angled away from the radar. The expansion of the summit eruptive vent within Halema‘uma‘u crater is clear, but differences between the images also indicate widening of Halema‘uma‘u itself, especially along the crater's southeast edge. These changes are a consequence of rockfall into the growing summit eruptive vent, which is floored by rubble.