Radar shows enlargement of summit eruptive vent

This image shows radar data acquired by the European Space Agency's Sentinel-1 satellite over Kīlauea Volcano on May 19 at 6:30 PM HST (left) compared to May 25 at 6:30 PM HST (right). 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 reflection. 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.

Comparing the two images shows that the summit eruptive vent continues to expand as the unsupported conduit walls collapse. As of the afternoon of May 25, the vent expansion included not only continued westward growth of the vent rim, but also a subsidiary pit on the north part of the floor of Halema‘uma‘u crater. The vent area is now approximately 90 acres, and we anticipate further enlargements over the coming days to weeks as subsidence of Kīlauea caldera, rockfalls, and small explosions continue.