Kīlauea summit gravity survey - September 23, 2020

During a gravity survey, HVO scientists measure the relative strength of gravity (gravimeter, bottom left corner of photo) between benchmarks. High-precision vertical positions from kinematic Global Positioning System (GPS, tripod and antenna middle of photo) help correct the gravity measurement for the effects of elevation changes. The south sulfur banks, exposed during the 2018 collapse events at Kīlauea summit are visible in the background of this image, to the right of the GPS antenna. USGS photo by A. Flinders.