PHOTO & ANIMATION: Pohoiki, Summit Caldera

The U.S. Geological Survey took this photo of Isaac Hale Beach Park and the Pohoiki boat ramp on the Sunday, Aug. 5, 2018, overflight. The active ocean entry and laze plume can be seen at lower left.

Pohoiki on Aug. 5, 2018. Click to enlarge. PC: USGS

This animated GIF shows a sequence of radar amplitude images that were acquired by the Agenzia Spaziale Italiana CosmoSkyMed satellite system. The images illustrate changes to the caldera area of Kīlauea Volcano that occurred between May 5, and Aug. 5, 2018, at about 6 a.m.

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.

Over time, expansion of the summit eruptive vent within Halema‘uma‘u crater and the widening of Halema‘uma‘u itself are obvious. Starting in late May, the development of several cracks outside Halema‘uma‘u is clear, and inward slumping of a large portion of the western, southwestern, and northern crater rim begins. Much of this motion appears to be coincident with the small explosions from the summit that have taken place on a near daily basis since early June.

The most recent scenes, acquired on Aug. 1, 2, and 5, show little overall motion, which is consistent with the slowing of deformation in the summit area over the past few days.